Amd ultra m.2 motherboard

Amd ultra m.2 motherboard DEFAULT

Born To Be the Fastest! ASRock Ultra M.2 Gen3 x4 32Gb/s Socket Provides the Ultimate Transfer Speed

TAIPEI, Taiwan, May 12, 2014 – As motherboard manufacturers unveiled their new Intel® 9 Series products one after another, we can see the proliferation of PCIe Gen2 x2 M.2 interface on Desktop motherboards very clearly. However, ASRock Inc. took the lead among other competitors once again. This time it's the Z97 Extreme6 which boasts "Ultra M.2 PCIe Gen3 x4" socket stands out. With its doubled transfer bandwidth, ASRock Ultra M.2 is able to completely break through the speed limit of SATA3 6Gb/s and blow others away!

Ultra M.2

The Secret of Ultra M.2

Ultra M.2 is one of ASRock creative innovations. Compared to normal M.2 with PCIe Gen2 x2 bandwidth, ASRock is the first one in the world to double the M.2 bandwidth to PCIe Gen3 x4! Furthermore, the layout of Ultra M.2 is also specially designed. On a regular motherboard design, the signal route starts from the M.2 device, goes through the onboard chipset, and finally reaches CPU. In contrast, by connecting the M.2 interface to CPU directly, ASRock Ultra M.2 has lower latency and pushes the I/O speed to a new level!

Shorter Latency

Experience The World's Fastest Speed With ASRock's Ultra M.2

The theoretical speed of Ultra M.2 is 32Gb/s, which is 6X faster than PCIe x1 M.2, and 3X faster than PCIe x2 M.2 (Chart 1). As for Ultra M.2 vs. normal M.2 comparison, we tested the read speed of Samsung XP941 PCIe x4 M.2 SSD on Ultra M.2 socket and reached 1.16GB/s, 46% faster than PCIe x2 M.2 socket (Chart 2). We also tested a PCIe x2 M.2 SSD on Ultra M.2 socket. Benefited from the direct linkage between Ultra M.2 interface and CPU, the PCIe x2 M.2 SSD read speed on Ultra M.2 socket is 8.8% faster than on normal M.2 socket. As shown in Chart 3, the lower latency of Ultra M.2 design does matter.

6x Faster

Designed For Tech Enthusiasts – Z97 Extreme6

As we may conclude now, ASRock Ultra M.2 is the key component to break the I/O performance barrier on current Desktop PC. With the proliferation of Ultra M.2 and M.2, the new era of I/O speed is about to come. If you are tired of the HDD performance bottleneck and looking for an ultimate I/O solution for your Desktop, ASRock Z97 Extreme6 is the only motherboard packs the world's fastest Ultra M.2 socket, ASRock Super Alloy technology, 12 Phase Power Design, Purity Sound™ 2, Dual LAN, SATA Express interface*, ASRock Cloud and other unique features. It is definitely the best motherboard for you!
* Support to be announced.

Z97 Extreme6 Photo

For more information, please visit:


M.2 vs Ultra M.2: What’s the Difference and Which Is Better? [MiniTool Tips]

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Summary :

Ultra M.2

Since the Ultra M.2 slot emerges in the market, it has attracted a large number of people. However, most of them are still confused about M.2 vs Ultra M.2. What is Ultra M.2? What’s the difference between M.2 and Ultra M.2? Let’s explore the answers together with MiniTool.

Lots of users intend to upgrade to Ultra M.2 SSD for the purpose of improving performance, while they are still confused about whether it is worthy and the difference between M.2 and Ultra M.2. Besides, the storage interfaces, compatibility, and some factors also bother many people.

You may encounter the same confusion as to the user from tom’s hardware forum:

I've tried to do my own research on this topic, but I'm unable to find the answer to my specific questions. I want to understand if Ultra M.2 socket uses 4x PCI-E lanes from the CPU. Would it be worth the increased SSD bandwidth to drop my single card down to 8x? What’s the difference between M.2 and Ultra M.2? My gaming is currently 1080P, so no immediate plans to upgrade my CPU to Ultra M.2. Thanks in advance for any help.

What Is Ultra M.2

What is Ultra M.2? To figure this question out, it is necessary to have an overall understanding of its history background, pros and cons, and key features.

Ultra M.2

History Background

The fact is that Ultra M.2 is just a marketing term that’s used by ASRock to distinguish the older 10/Gbps M.2 socket (M.2) and a full 32/Gbps M.2 socket (Ultra M.2). That’s why you can’t search for any detailed information about the Ultra M.2 form factor in Wikipedia.

As you might know, the older M.2 SSDs are not available for the maximum bandwidth, while the bandwidth has a significant impact on the performance of SSD. With the improvement of form factor technology, the Ultra M.2 slot takes advantage of those SSDs that are available for truly extreme bandwidth. 


Based on the older M.2 slot, Asrock developed its own Ultra M.2 slot that can be used to support up to 4GB/s of bandwidth. This is because the Ultra M.2 slot relies on PCIe 3.0 and a more advanced interface. If it’s used on the PCIe 4.0 motherboard interface, the Ultra M2 SSD can even support up to 16GB/s bandwidth.

As the new Ultra M.2 slot provides larger bandwidth, it stimulates a big potential of some modern SSDs such as Samsung. According to the report of ASRock, its Ultra M.2 socket is 46% faster than a typical M.2 socket. Another distinctive feature is that the Ultra M.2 sockets can be connected to the CPU directly without going to the chipset.


However, the Ultra M2 socket has its own drawbacks. For example, the Ultra M.2 slot on the Intel Z97 platform PCIe 3.0 can only be supported by the microprocessor itself. Besides, it is reported that Ultra M.2 will consume 4 PCIe lanes that are used for GPU X16. So, it won’t make any sense to choose an Ultra M.2 SSD if the slot uses PCIe lanes from the chipset.

If your computer is using a relatively old graphics card or CPU, the graphics processing unit and central process may slow down due to the Ultra M.2 slot. For instance, the 16 PCIe 3.0 lanes of a CPU are used to connect a graphics card in the 16 PCIe 3.0 model or a dual GPU configuration. Once an SSD is plugged into the Ultra M.2 slot, the bandwidth between the graphics processing unit and CPU processing will be cut down by half.

In other words, you have to sacrifice a certain amount of GPU performance to get maximum SSD performance due to the insufficient bandwidth. Well, not all GPU processing will consume a massive amount of PCIe bandwidth. So, if you want to get an excellent graphics performance, Ultra M.2 may not a good option.

According to the above information, I believe that you already have an overall understanding of the Ultra M.2 slot. Let’s further exploring another important topic - M.2 vs M.2 Ultra.

M.2 VS Ultra M.2

What the difference between M.2 vs Ultra M.2? Some users think that Ultra M.2 is exactly the same as M.2. The Ultra M.2 slot is a marketing name used by ASRock to differentiate a full 32/Gbps M.2 slots and the older 10/Gbps M.2 slots.

One of the most distinctive features is that the Ultra M.2 slots equipped with the PCIe 4.0 lanes can be connected to CPU directly without going to the chipset, while the M.2 slots with PCIe 2.0 are connected to CPU through the chipset.

Here we will explore the difference between M.2 vs M.2 Ultra from the following 2 aspects.

#1. Data Speed

According to the user report, the M.2 and Ultra M.2 SSD have the same data speed. Is it true? If you are searching for an M.2 or Ultra M.2 SSD, you will find there’s a slight difference between them. In most cases, Ultra M.2 has faster data speed than the M.2 slot. This is because Ultra M.2 takes advantage of the maximum bandwidth of an SSD, while sometimes it may slow down the CPU and graphics processing.

In reality, the data speed depends on the specific interface and controller of a drive. Do you want to know the real performance of your M.2 SSD? Now, you can use MiniTool Partition Wizard. It can help you test disk performance with ease.

Until now, this trusted software has helped lots of users to make a comparison about disk performance such as RAID 0 vs RAID 1, hardware vs software RAID, SanDisk Extreme vs Extreme Pro, and so forth.

Besides, this utility boasts many powerful features such as convert dynamic disk to basic disk, change cluster size, convert NTFS to FAT without data loss upgrade hard drive, rebuild mbr, etc.

Click on the following button to download MiniTool Partition Wizard and then install it on your computer. Now, let’s see how to perform a disk benchmark using this software.

Free DownloadBuy Now

Step 1. Run MiniTool Partition Wizard to get its main interface and click on the Disk Benchmark feature on the top toolbar.

click on Disk Benchmark

Step 2. Select the drive letter of the SSD that you want to test from the drop-down menu. Here you can further specify the test parameters and click on the Start button.

Tip: The test time depends on how large the transfer size spans.

click on Start button

Step 3. Then wait for a few minutes, you will get the disk performance including transfer size, the random/sequential reading and writing speed, etc.

the data transfer speed

#2. Storage Interfaces

There are 3 major storage interfaces for M.2 storage devices that you can choose one depending on the operating system and motherboard. The Legacy SATA interface is used for SATA SSDs. The PCI Express interface is used for PCIe SSDs through the AHCI driver and PCIe lanes. Another surging storage interface is NVMe that’s used for PCIe SSDs through NVMe driver.

At present, the Ultra M.2 sockets are mainly used for the NVMe PCIe 4.0 SSDs. According to a survey, the Ultra M.2 SSDs mainly come from Samsung 970 EVO series, while the M.2 SSDs come from different brands such as Samsung, Kingston, WD Black, SanDisk, and so on.  

Is Ultra M.2 SSD Worthy

Right now, you may be wondering whether it is worth choosing the Ultra M.2 socket. The answer depends on your specific needs. If you want to get a dramatically high disk performance and don’t care about the price, you can consider switching to the Ultra M.2 SSD.

Bear in mind that the data speed depends on the specific storage interface. When choosing an Ultra M.2 SSD, you should check if the storage interface is SATA, NVMe, or PCIe 4.0. Usually, an NVMe SSD is faster than a SATA SSD.

Besides, you should check if your graphics card and CPU match the Ultra M.2 slot. This is because sometimes it will slow down the central processing and graphics card processing. Right now, you may have a deep understanding of M.2 vs M.2 Ultra.

How to Upgrade to SSD Without Reinstalling OS

No matter what you choose M.2 or Ultra M.2, you need to upgrade your previous hard drive. So, how to upgrade your hard disk to SSD without any data loss? MiniTool Partition Wizard is what you need. It not only helps you test the disk benchmark but copy the whole disk to an SSD.

Note: Since the free edition does not support this feature, we recommend you to install the MiniTool Partition Wizard Pro or more advanced edition for this operation. Click here to know more about edition comparisons.

Buy Now

Step 1. Connect the M.2 SSD to your computer and launch the software to get its main interface.

Step 2. Click on Copy Disk Wizard feature at the left pane and click on the Next button in the pop-up window.

click on Copy Disk Wizard on the left pane

Step 3. Select the original hard disk that you want to copy and click on the Next button.

Step 4. Now, select the target disk that you prepare to be stored and click on Next to continue. Then click on Yes to confirm this operation.

select the target disk

Note: All the data on the target disk will be deleted during the copy operation. So, please make sure you back up all important data in advance.

Step 5. Select a copy method based on your needs and click Next to continue.

select a copy method and click Next

Step 6. Click Finish in the pop-up window and click Apply to execute this operation. Right now, all the data on the previous hard disk have been transferred to the SSD.

What is Ultra M.2? Would it improve my SSD performance? A lot of people think it is the same as the M.2 socket. Really? I found the answers from this post. Perhaps here’s what you are searching for.Click to tweet

What’s Your Opinion

Here comes the end of the post. Have you understood the Ultra M.2? What’s the difference between M.2 and Ultra M.2? I believe that you already have a deep understanding of them. You can use MiniTool Partition Wizard to upgrade to SSD with ease.

If you have any questions, you can send us an e-mail via [email protected]. We also appreciate any opinions about this topic in the comment area.  

Ultra M.2 FAQ

What does M.2 X 4 mean?

M.2 is known as Next Generation Form Factor that’s designed for replacing various devices especially SSDs. The X4 refers to the number of PCIe lanes used by the M.2 form card. Usually, the old M.2 card has only 2 PCIe lanes.

What does NVMe PCIe 4.0 mean?

NVMe PCIe 4.0 refers to a kind of NVMe SSD that supports the PCIe 4.0 motherboard interface. You can get higher input/output performance per second (IOPS) and potentially lower power consumption, which depends on the form factor and the number of PCIe lanes.

What the difference between NVMe and PCIe?

NVME is short for Non-Volatile Memory express. It is a specification set for SSDs and other storage devices that are used to attach the PCIe motherboard interface. For instance, not all PCIe SSDs are NVMe SSDs, but all NVMe SSDs must be PCIe.

Is SSD faster than M.2?

M.2 vs SSD, which is faster? The data speed of M.2 SSD depends on the specific storage interface. If your M.2 SSD is a B-key socket and designed to support NVMe protocol, its data speed is at least 3 times faster than a SATA SSD.



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Position: Columnist

Fall in love with the hardware technology in early 2008. Now, Ariel has been a professional columnist for partition management publications. Graduated from Purdue University in 2010, Arial has about 10 years of working experience in the field of hardware technology. As a columnist on MiniTool, Ariel has provided numerous solutions ranging from data backup, disk management, and data recovery. These solutions helped millions of users fix all kinds of tricky problems. Ariel was born in Pennsylvania and lives with her husband and a lovely dog. She always says “Life is full of magic, but writing means the world to me.”

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ASRock unveils the Ultra M.2 Socket, fastest in the world

ASRock has just unveiled its new Ultra M.2 PCIe Gen3 x4 connection interface that is said to double its transfer speed bandwidth, and blow SATA 3 6GB/s out of the water. The new Ulra M.2 interface is much faster due to a direct connection to the CPU, whereas older M.2 interfaces passed through the chipset before being routed to the CPU. This means that the latency is much lower and faster transfer speeds are the result.

ASRock unveils the Ultra M.2 Socket, fastest in the world 1 |


"The theoretical speed of Ultra M.2 is 32Gb/s, which is 6X faster than PCIe x1 M.2, and 3X faster than PCIe x2 M.2. As for Ultra M.2 vs. normal M.2 comparison, we tested the read speed of Samsung XP941 PCIe x4 M.2 SSD on Ultra M.2 socket and reached 1.16GB/s, 46% faster than PCIe x2 M.2 socket. We also tested a PCIe x2 M.2 SSD on Ultra M.2 socket. Benefited from the direct linkage between Ultra M.2 interface and CPU, the PCIe x2 M.2 SSD read speed on Ultra M.2 socket is 8.8% faster than on normal M.2 socket. As shown in Chart 3, the lower latency of Ultra M.2 design does matter," ASRock said in a release.

ASRock unveils the Ultra M.2 Socket, fastest in the world 2 |

ASRock says that for now, the new Ultra M.2 interface will only be available on the new ASRock Z97 Extreme 6 motherboard which features other high-end features such as; ASRock Super Alloy technology, 12 Phase Power Design, Purity Sound 2, Dual LAN, SATA Express interface, and ASRock Cloud.


Charles Gantt

A web developer by day, Charles comes to TweakTown after a short break from the Tech Journalism world. Formerly the Editor in Chief at TheBestCaseScenario, he now writes Maker and DIY content. Charles is a self proclaimed Maker of Things and is a major supporter of the Maker movement. In his free time, Charles likes to build just about anything, with past projects ranging from custom PC cooling control systems to 3D printers. Other expensive addictions include Photography, Astronomy and Home Automation.

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  • PCIe Gen3 x16 interface
  • Supports M Key type 2242/2260/2280/22110 M.2 PCI Express module Gen3 x4 32Gb/s
  • Supports Intel® VROC technology
  • Fully support Intel® latest NVMe M.2 SSD
  • Variable speed cooling fan
  • ASRock Quad M.2 Card Utility

This model may not be sold worldwide. Please contact your local dealer for the availability of this model in your region.

  • Overview
  • Specification
  • Support

Bootable M.2 RAID Support

Supports up to 4 PCIe Gen3 x4 NVMe M.2 SSDs on AMD X399 platform and Virtual RAID on CPU (VROC) technology on Intel®X299 platform*. Allows you to create a bootable RAID array with up to 4 M.2 SSDs**.

All-Aluminum Cover & Fully Cover Thermal Pad

The 11-cm-long thermal pad is able to fully cover every NAND flash on M.2 SSD, transferring heat generated by the high speed M.2 SSD onto the aluminum cover. Extend the longevity of each devices.

Adjustable Cooling Fan

Apart from the large aluminum cover, the 5cm cooling fan can not only quickly dissipate the heat but also lower the temperature to ensure a stable performance of M.2 SSD. What’s more exciting, the fan speed can be adjusted via a switch located on the PCB, giving a more flexible usage.

The Shortest Trace

The onboard four M.2 sockets are laid out on PCB at an angle (45 degrees). The shape is optimized to keep the traces as short and direct as possible. Designed with the right trace shape in order to make sure each M.2 socket carries good enough current, thus providing maximum performance and stability.

A Flexible & Convenient Utility

A dedicated utility that applies with the onboard FAN switch to monitor vital info and control fan speed easily on ASRock ULTRA QUAD M.2 Card.

More M.2 expansion space!

Desire more ASRock Ultra Quad M.2 Cards installed for unbeatable M.2 expansion? No problem! Use the onboard switch and you can manage multiple Ultra Quad M.2 Cards effortlessly.

A 6-pin 12V Power Design

High speed NVMe M.2 SSD requires more power! Therefore, there’s a 6-pin 12V power connector onboard to ensure M.2 storage devices have enough power to perform perfectly.

  • Dimensions

    - 9.6-in x 4.4-in

  • Interface

    - PCI Express 3.0 x 16 interface

  • Connectors

    - 4 x Ultra M.2 Sockets
    - Supports M Key type 2242/2260/2280/22110 M.2
    - PCI Express module up to Gen3 x4 (32 Gb/s)
    - 1 x Graphics 12V Power Connector

  • Accessories

    - Quick Installation Guide, Support CD
    - 4 x M.2 screws


M.2 motherboard ultra amd

raknarius said:

lol so confusing i dont think ill ever get an answer

Click to expand...

raknarius said:

i didnt pick a motherboard yet, im looking at modern motherboards with the ultra m2 slot

Click to expand...

You have a very clear answer for the specific motherboard you implied you were looking at. Not that that answer is useful anymore now that we know you have no intention of getting that motherboard.

"Ultra M.2" appears to just be ASRock's term for a PCIe 3.0 x4 M.2 slot. That used to be a somewhat special thing, but now it's the norm. For any modern motherboard*, you will have no issue using a single PCIe 3.0 x4 SSD and still having your graphics card run at full x16 bandwidth. Intel motherboards will have the M.2 slot connected through the PCH (which doesn't share bandwidth with the primary PCIe x16 slot), and AMD motherboards use a x4 connection from the CPU that's dedicated for M.2 storage (so it too does not share bandwidth with the primary PCIe x16 slot).

*With AMD, you'd need to get a Ryzen CPU/APU. With an Athlon, you'd only get PCIe x2.


2x NVMe in RAID 0 — Double The Speed? — PCI-E 4.0 Tested

Is M.2 SSD support on AMD motherboards causing confusion?

For the most part, installing a PCIe NVMe SSD into the M.2 slot on an Intel motherboard will result in you obtaining full speed thanks to the fact that where there's PCIe M.2 SSD support, you can expect the full PCIe 3.0 x4 bandwidth that 's needed to take advantage of the likes of Samsung's 900-series SSDs. Similarly, one or more of the M.2 ports on Intel Z370 boards can also cater for SATA M.2 SSDs too, although these have often had questionable layouts with only the primary heatsink-equipped ports being compatible with slower SATA-based SSDs, as I've blogged about before.

However, motherboard manufacturers appear to be assuming different stances on how their M.2 ports on AMD X470 boards are configured, and in many cases they're illogical and even downright confusing. The issues come in various guises, just to make things worse. Starting with good ol' SATA M.2 SSD support, the issue of which ports are compatible with them has reared its head again. Several boards I've seen, including Gigabyte's X470 Aorus Ultra Gaming, have two M.2 ports, but only one is compatible with both SATA and PCIe SSDs. With this board in particular, the issue is that this port is the one with the M.2 heatsink.

The second issue, and this is present on the same board, is that the SATA-compatible M.2 port is the only port that offers full PCIe 3.0 support. The second slot is limited to PCIe 2.0, which will see speeds limited to around 1,800MB/s, so it's a pretty pointless inclusion seeing as current M.2 SSDs are either PCIe 3.0 x4-based and offer speeds that will be bottlenecked by PCIe 2.0's maximum bandwidth,  or are SATA-based and thus not compatible with that port anyway.

To make things worse, while MSI at least states that the second port is limited to PCIe 2.0, Gigabyte was merely stating that it offered PCIe x4 speed but conveniently missed out the fact that it's not PCIe 3.0, that is until we contacted them, after which the issue was rectified on the official specs page. To stress, PCIe 2.0 is much slower than 3.0, even if we're dealing with x4 speed/lanes, so it's really important that manufacturers state this clearly. MSI has also added SATA M.2 SSD support to this slot on most of its X470 boards, which makes more sense given it's the one that usually lacks a heatsink, plus you're able to use SATA M.2 and PCIe 3.0 x4 M.2 SSDs at the same time.

Asus isn't immune to the issues, either. As well as previous motherboards - including Intel-based ones - stating SATA M.2 support when it wasn't actually the case, the ROG Crosshair VII Hero appears to have a very odd layout and PCIe lane allocation. What visually appears to be its primary M.2 port and the one that is equipped with a heatsink out of the box, is actually the port that lacks its own dedicated four PCIe lanes from the CPU, but it doesn't even get them from the chipset like the lower 16x and 1x PCIe slots do. As a result, if you use it with a PCIe M.2 SSD, it will steal lanes from the 16 lanes allocated to the two primary 16x PCIe slots, reducing the bandwidth to your graphics card to just eight lanes instead of 16. 

As has been proven in numerous benchmarks, the difference between x8 and x16 speed for GPUs doesn't make that much of a difference in games even with high-end graphics cards, so the Crosshair is at least able to offer full PCIe 3.0 x4 bandwidth in either M.2 slot, but there is nothing in the Crosshair VII Hero's manual that warns of this specific situation. So, while your PCIe M.2 SSD will achieve its full potential in the top M.2 slot, your graphics card might have reduced bandwidth, while using the lower M.2 port will see both the SSD and graphics card both receiving full bandwidth. In my mind, Asus should not only make this clear in the instructions, but it should also move the heatsink to the lower slot out of the box, as it doesn't do potential owners any favours.

So, if all that is as clear as mud (hopefully it makes some sense at least), you need to make sure of a couple of things before you invest in an X470 motherboard if you intend to use an M.2 SSD. Firstly, if that SSD is PCIe-based, check which M.2 ports offer the full bandwidth, and by that I mean PCIe 3.0 x4, not just x4 and not just 3.0 - both. If it just lists x4, it seems to be the case that it will actually be running at the 2.0 standard and not 3.0. Secondly, check which PCIe M.2 slot you should use - in the case of the ROG Crosshair VII Hero, using the wrong slot could see it steal bandwidth from your graphics card. Finally, if you're planning on using SATA M.2 and PCIe 3.0 x4 M.2 SSDs together, check whether the board supports both at the same time and whether the slot you'll be using for the PCIe SSD will actually offer the full bandwidth, as many don't.


Similar news:

ASRock Z97 Extreme6 Review: Ultra M.2 x4 Tested With XP941

As part of our review, ASRock sent us the 512 GB Samsung XP941 M.2 drive to test how ASRock has implemented the feature. For more information on the drive, check out Kristian’s review here. Kristian, due to his Z87 setup, had to use an M.2 x4 to PCIe adapter card, whereas with the Z97 Extreme6 we can test it direct.

On the Z97 motherboards we have seen so far, they have all implemented an M.2 x2 slot, with the two lanes coming from the eight PCIe 2.0 lanes possible off of the Z97 chipset. These slots are often also SATA capable, and share bandwidth with other SATA ports, a PCIe 2.0 x4 slot or the SATA Express implementation. The Z97 Extreme6 does this with its own M.2 x2 slot, but it has the Ultra M.2 x4 slot that comes direct from the CPU.

The Haswell CPUs for the Z97 platform have 16 lanes of PCIe 3.0 which are split into two lots of eight. One of these eight can be split into two lots of four, and it is typical to see on a motherboard a multi-GPU arrangement of x8/x4/x4 from the CPU. It is these last four lanes that ASRock has adapted for its M.2 slot, which means that when an M.2 drive is placed into the x4 slot, it will reduce the bandwidth of the first two PCIe slots down to x8/x4. This also disables SLI, due to NVIDIA’s requirement for x8 PCIe lane allocation (either PCIe 2.0 or 3.0) for each graphics card.

We tested the XP941 in both the x4 and x2 slots to find the general performance values of the drive when restricted by the x2 or given full reign of the x4. Because the x4 is rated at PCIe 3.0, ASRock is claiming a peak bandwidth of 32 Gbps, or 4 GBps, for drives attached. This would be a significant increase over the standard state of SATA storage, which tops out at 600MBps in real world implementations over a 6 Gbps connection. That would also imply that the 32 Gbps from the x4 should give 3.2 GBps as an upper limit.

We ran a series of tests with the XP941 in the M.2 x4, both while the integrated graphics was enabled and a discrete GPU (dGPU) in the first PCIe slot, and the M.2.

ASRock Z97 Extreme6 M.2 Performance
  M.2 x4 M.2 x4 w/dGPU M.2 x2
  Read Write Read Write Read Write
AS SSD 1095 918 1095 942 765 647
ATTO QD4 1015 1074 1028 1081 679 827
ATTO QD10 1013 1074 1020 1079 687 829
IOMeter 1347 1347 828
HDTach 1047 905 607

Using the drive in the M.2 x4 slot, with or without a discrete GPU in place, gives peak readings about the same, although with the discrete GPU in place ATTO shows some improvement in small transfer sizes (+30% at 4KB with QD10).

However the upshift from x2 to x4 shows the effect of a drive restricted against a drive that can stretch its legs. We move up from 765 MBps read to 1095 MBps read in AS SSD, a 43% speed up. We are still a way away from the 32 Gbps suggested by ASRock that this slot can handle, but it does mean the headroom is there for faster devices.

Moving on to the effect of losing lanes on discrete GPU gaming, we took the system with the M.2 equipped and tried our benchmarks on a single HD7970 (comparing x16 to x8) and two HD7970s in CrossFire (comparing x8/x8 to x8/x4).

Effect on Average FPS on PCIe 3.0 x16 to x8
  PCIe 3.0 x16 PCIe 3.0 x8 Difference
F1 2013 127.6 127.5 -0.1%
Bioshock Infinite 71.0 71.4 0.6%
Tomb Raider 44.6 44.4 -0.4%
Sleeping Dogs 48.3 48.1 -0.4%
Company of Heroes 2 42.9 42.3 -1.4%

On single GPU gaming, at our 1080p Maximum settings presets, gave almost zero difference with the bandwidth difference. The biggest drop was 1.4% for Company of Heroes 2. If this is the worst effect of dropping down from PCIe 3.0 x16 to x8, then I am encouraging all manufacturers, especially those making mini-ITX motherboards, to seriously consider ways to implement a M.2 x4 slot on their products.

This also has an effect on laptop computing, especially those with integrated discrete graphics cards. It means that the laptop manufacturer can implement either one or two M.2 x4 drives in a notebook and still have eight lanes for the GPU which will not be adversely affected in frame rates.

Now on to two-way CrossFire:

Effect on Average FPS on PCIe 3.0 x8/x8 to x8/x4
  PCIe 3.0 x16 PCIe 3.0 x8 Difference
F1 2013 117.5 113.6 -3.3%
Bioshock Infinite 133.3 131.8 -1.2%
Tomb Raider 87.2 88.0 0.9%
Sleeping Dogs 94.1 93.7 -0.4%
Company of Heroes 2 42.4 42.3 -0.3%

Here we see a bigger drop of 3.3% with F1 2013, and the bandwidth drop might affect us more if we had bigger screens at our disposal or a multi-monitor setup. But even 3.3% is not that bad, moving frame rates from 117.5 to 113.6 FPS is an arguable change at best.

All this points to one of several outcomes:

  • NVIDIA release their x8 lane restriction for PCIe 3.0 so users can implement SLI with M.2 x4
  • Intel increases the lanes on their mainstream CPUs to 20, giving x8/x8 allocation on PCIe and four lanes configurable M.2/SATAe
  • Nothing happens, because the performance on one GPU is not badly affected.

I will be hoping for a combination of the first two, just because it would open up more possibilities in this world of desktop computing.

OS Installation

A topic that has arisen on forums since the launch is whether the M.2 drives can be used as boot drives. For UEFI installation, the detection algorithm in the firmware has to be active to see the drive at the install prompt, however for Legacy installation the drive needs to implement its own firmware at POST. As the XP941 does not have initialization drivers, my Legacy Windows 7 install that I normally do for reviews, while it saw the drive at the OS installation screen, it was unable to hook the drive in to install. This is for both the M.2 x2 and M.2 x4 slots on the ASRock motherboard. Placing the drive into an ASUS motherboard showed no drive at all for Legacy installation, however Kristian has been in contact and confirmed that they are working on enabling UEFI installation for M.2 in a future BIOS update, as should all the manufacturers be if they have not already.

When the motherboard manufacturers have updated UEFIs, the following table should be relevant:

  Legacy OS Intall UEFI OS Install
M.2 without M.2 POST Firmware
(e.g. Samsung XP941)
No Yes
M.2 with M.2 POST Firmware
(e.g. Plextor M6e)
Yes Yes



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