SM951 as OS boot device information

Well, I have my Z170 Extreme7+ up and running. Nice board and not any problems with it so far.

The single new SM951 I have in it now, not as an OS drive, performs normally about the same as the SM951 I have on my Z97 Extreme6 board. Different benchmark test:



So now off to remove the SM951 in my Z97 PC and see what I get.

A video card should not affect the performance of these SSDs on the Z170 platform, the PCIe 3.0 lanes from the CPU are not used for IO devices.

The program commonly used to secure erase SSD is called Parted Magic. DO NOT use Parted Magic to secure erase an SM951, as stated above!!!

The Samsung Magician software does not fully support the SM951, so don't expect it to work correctly.

If the RAID 0 arrays of these SSDs do not work well on the Z170 platform, I would blame the IRST software IMO.

More later...   OF COURSE just got called into work...

Sorry Ronzer, I'm not sure why you are getting that result since I don't know all your UEFI, Windows 10 installation, and IRST RAID 0 details.

I promise you we will go over all of that and see what we can do for you. Yes those things matter and can make a difference, as... umm... you'll see.

So I had to play with computers at work today, POS machines, which means Point Of Sale, not

Then I come home to remove my first SM951 (OS drive) from my ASRock Z97 PC, after cloning it to a "lowly" Samsung 840 Pro. Installed it with the other in the Z170 PC, in the M2_1 and M2_2 ports. I'm running the Z170 PC on the same Win 10 installation (key) as my X99 PC, so only temporary. Anyway... just getting the dang SM951s to appear in the IRST utility in the UEFI is a fun little procedure, as you said.

Did you happen to see what the IRST Windows UI states is the "PCIe link speed" in the Manage - Advanced info display? I don't know what to think about that.

Ok, I get no thrill out of showing you this, honestly... but in general I'd say it seems to be good news. This is two 256GB AHCI SM951s:



IMO, this is good, could be better in theory. Don't be alarmed by the size of the volume, it normally is 476GB, but I have over provisioned it myself. NOT that I think that is a key to performance, except for maintaining long term performance.

AS SSD does not look as good, but is just different:



Sorry but I'm passing out, gotta sleep and work tomorrow, which is today already.

First question for you, when you create the RAID 0 array, you choose a stripe size. The Intel default is 16K, which gives the best 4K performance, but worst sequential speed. The results you see above is 128K stripe size. 64K should be good too... but with these SSDs, who knows. I ONLY tried 128K so far.

I hope this makes sense, I'm typing with my forehead...

TimH, I was talking about the IRST User Interface in the IRST Windows program that is available if you install the full IRST driver and Windows program package, the Intel Rapid Storage Technology driver and utility ver:14.5.0.1081 on the Win 10 section of the Z170 Extreme7+ Download page.

http://www.asrock.com/mb/Intel/Z170%20Extreme7+/?cat=Download&os=Win1064

I'm using the latest version of that software I downloaded from Intel, version 14.6.0.1029:

https://downloadcenter.intel.com/download/25165/Intel-Rapid-Storage-Technology-Intel-RST-RAID-Driver

ASRock is working on updating the mother board download pages with this version.

Below is what I was talking about, this is one of the screens of the IRST Windows program UI, shrunk down from its normal size. Check the PCIe link speed under Advanced on the left:



This 4000 MB/s figure is interesting and I wonder about it for several reasons. Also notice the PCIe link width: x4, which is what the Ultra M.2 interface is, x4.

Intel refers to that internal interface in the Skylake technical documents, which is part of the Z170 chipset, not as PCIe but DMI3. DMI3 is really PCIe 3.0 but NOT the PCIe 3.0 lanes that are part of a Skylake CPU, but the Z170 chipset. The Z97 platform used the CPU's PCIe 3.0 lanes for the Ultra M.2 interface, and the Z97 chipset did not have PCIe 3.0 support, only PCIe 2.0.

Anyway, back to the 4000 MB/s figure. Is that rate from an x4 interface? It must be.

Next, is that a maximum theoretical figure, such as SATA III being 600 MB/s, but when the actual data transfer protocol is taken into account (10 bits transferred for every 8 bits of user data), the real world SATA III speed is about 540 MB/s maximum. PCIe 3.0 uses a different protocol that has less overhead (for SATA, 10 bits transferred for 8 bits of data has 2 bits of overhead) but still may not be 4000 MB/s.

The IRST UI (or Utility, I call it the IRST UI) in the UEFI is not the same as the IRST Windows UI, it is simpler but allows the creation of RAID arrays. The entry for it (when it appears) is at the bottom of the Advanced screen. Getting it to appear is another story...

In the UEFI Boot screen, at the bottom is an option called CSM, normally Enabled. One of its options is Launch Storage OpROM Policy. If you set that to "UEFI only", save and exit, and go back into the UEFI UI, you should see an entry for the IRST Utility on the Advanced screen.

It's possible to set CSM to Disabled and the same thing will occur, but you can't do that and boot into Windows unless Windows was installed in a certain way, and there are other requirements/restrictions. I need to write up that procedure and post it in the forum. Someday soon...

I never said the IRST Windows program would increase your benchmark results. I was simply commenting on Intel's statement about 4000 MB/s being the bandwidth of one of the Ultra M.2 x4 ports.

The "4000 MB/s" in the IRST program is not a reading of the ports speed, it is simply text added to that screen.

Now let's really see if we can fix things for you and Ronzer. I have no idea what the UEFI settings I'll talk about are set to on your boards, so I'll just go over them.

You MUST maintain these settings in the UEFI on each boot. Now besides SATA mode set to RAID, these also must be reset after a UEFI clear or update.

SATA mode set to RAID (duh.) 

In the Boot screen at the bottom, CSM option. If you are using it Enabled (if you don't know the difference, you're using Enabled), find the Launch Storage OpROM Policy option and set it to UEFI Only.

In the Advanced - Storage Configuration screen, do you have three options listed, one for each of the Ultra M.2 slots, M2_1, M2_2, and M2_3. These options are NOT the same as the simple M.2 port listing for each drive.

That option is RST Pcie Storage Remapping, set it to Enabled for each of the M.2 ports you are using. All of them for you guys.

Ok, done with the UEFI, now fire up the IRST Windows program. Go to the Manage option for the SM951 RAID volume. Click on Advanced to reveal more options.

You might only see one, Write-cache buffer flushing: The word in black text is the current setting, the word in blue text is not being used. Set it to Disabled.

If it was NOT Disabled, you'll see four Caching options. The best overall performance is "Write back", try that first. You can change these easily anytime. I have mine set to Write back so you see that as my Cache mode in this example:



Question for TimH and Ronzer, do you see each of your SM951s listed in the Storage Configuration screen when they are part of a RAID array?
I'm also forgetting, do you have Windows installed on the RAID 0 array?

Any questions, etc, post them here and if these things help you or not.

You guys are kinda beating the heck out of your SSDs with all these benchmarks. Each run is normally at least a Gigabyte of test data, AS SSD is 3 - 4 Gigabytes written every test. I hope you are running the Windows 8 - 10 Optimize (TRIM) feature under Tools in the Properties display for each drive. It runs on a schedule, but you can run it manually any time. Anvil also has a manual TRIM tool. Samsung's no doubt won't work with the SM951, but I never tried.

I contacted ASRock support, they suggested I try Intel 750 SSDs with the U.2 kit as seen here: