Low 4K scores for Taichi & 960 EVO

parsec wrote: Here's my 500GB 960 EVO in my ASRock X370 Killer SLI/AC board: Looking at a benchmark result does not begin to tell the whole story of how it was achieved. Yes, storage drive bench marking has its tricks and tweaks to get better results. We can get some clues regarding what some of the situation is by looking closely at each of the screenshots in this thread. First, if the drive being tested is the OS/Windows C: drive, the results will be lower than a non-OS drive. The benchmark program does not own the PC when it's running, so any IO done by Windows will interrupt the benchmark. Any non-OS drive will not have the benchmark interrupted by other IO. The second and third Crystal screenshots in the first post that are supposed to be from a Gigabyte X370 board, show the drive being tested were the D: and H: drives. Both not the C: OS drive, so the results will be better. The first screenshot has the drive information cut off, so no idea. All the other Crystal screenshots from ASRock boards in this thread are of the C:/OS drive. So not an identical comparison. Second, the 250GB EVO shown (third Gigabyte screenshot in the first post) which is overall exceptional (with a 50MB/s 4K read) shows 0/233GiB used. That is an empty, new SSD, which will always have great performance compared to a SSD that has been used. Empty is more important than new, but new also helps provide a better result. Next the things we cannot see: CPU OC, Memory OC, CPU power saving option settings, Windows Power Plan option settings, and Windows write cache buffer flushing setting. Do we know about any of these things in the superior benchmark results? No. How did I get the 60MB/s 4K Read speed? I disabled Cool n Quiet and C State support in the UEFI. Even though IO is not CPU intensive, the latency caused by the processor cores switching in and out of the high (C6) C State can be seen in benchmark results. I know it shows up with Intel systems and now I know the same is true for AMD Ryzen. Not a surprise. Gigabyte is (in)famous for setting their default UEFI/BIOS options to provide better performance when their mother boards are tested in reviews, with all default settings. Meaning CPU power saving options on Auto is really Disabled. My ASRock X370 board's UEFI and Cool and Quiet, C6 and Global C6 Support Enabled by default. I'm using the AMD Ryzen Balanced Power Plan, but this applies to any power plan. PCI Express Link State Power Management is set to Off. The Ultra M.2 slots use the PCIe lanes from the CPU, so any power saving on those will cause latency and slower speeds. I haven't tried the High Performance power plan, which I know gives the best benchmark results with Intel systems. I will say in general the 4K performance of any SSD seems to be lower with my Ryzen system than my Intel systems. Of course, Intel has had PCIe 3.0 M.2 support since their Z97 boards released in 2014. We are using the first AMD Ryzen NVMe Option ROMs in our board's UEFIs, which should be improved down the road. Here's one fully tricked benchmark of a 960 EVO on an Intel Z270 board:

Edited by GenesisDoes - 29 Apr 2017 at 2:31am

CHO wrote: In case of 4K Q32T1 settings, R/W performance will be under 400MB/s but if you change the settings to 4K Q32"T4", you will be able to get over 1,000MB/s @Ryzen environment. Pls check if your setting is correct or not on CDM.

And we have a winner!

Why did I not include this in my first post, as I said to look closely at the screen shots! The "T4", or four Threads setting, in Settings, Queues and Threads, is seen in all of the Crystal results in the first post for the other boards. You can set four or more threads in the Sequential Q32T1 test too, as well as a higher Queue depth than 32, the maximum for AHCI, but not for NMVe.

But there are differences in the standard 4K, and Q32T4 4K tests that are not simply caused by using more threads. We have seen the SATA SSD 4K speeds are lower on our boards too, I don't know what apparently is causing that.

zlobster wrote: Also, did anyone check thermals during the tests? We all know that NVMe devices are really prone to thermal throttling. 4K random, being last of the read tests, mean that the drive itself has been warmed up in advance, hence possible throttling.

That is a possibility, but in my case it wasn't an issue.

Samsung does not provide their white paper for the 960 series, but did for the 950 Pro, and I have a copy. The throttling threshold temperature for the Samsung 950 Pro is 74° C. Beyond that performance drops quickly, at 75.5° C it is at 75%, and at 76.5° C it is at 50%. At 79° C, it is at 10MB/s! HWiNFO shows two temperatures for 960 SSDs, and mine was never over ~45° C for the NVMe controller. I doubt that the 960 series is any different than this, or throttles earlier than the 950 Pro.

The main complaints here are the 4K Q32T1 results, which is the second test of the set of four. If thermal throttling was on at that point, the following tests should be worse than the results shown in this thread. But I cannot say that there wasn't any thermal throttling happening in some or all of the Crystal results posted by ASRock users. It doesn't seem to be very much, if any at all.

One little trick you can do with Crystal, is to run each test individually. Instead of clicking the All button, click on one of the four tests, like the 4K Q32T1 box. Only that test will run, and you can wait for the SSD to cool off a bit, and then run another. If your 960 is throttling during only one of the four tests, it really has no cooling at all, and you should do something about that.

So just run the 4K Q32T1 test and see what you get. Try changing the number of threads to four (T4) in Settings.