I was able to pick up two 750GB P4800X for £300 from a friend who was selling up all his older hardware ( was a spur of the moment purchase ). So I thought i’d have some fun and RAID 0 them but before I do I was wondering if anyone knows how much latency AMD’s RAIDXpert2 would add to the drives.
Would it negate the benefit of optane’s low latency or would it still be alot lower than traditional NVMe M.2 drives?
Not sure about that specific setting but I did notice enabling read+write back cache had a 100x increase in response times (30ms vs 0.3ms). So disabling cache could be a possible thing for you to try if they are higher then you expect
The latency is still good, especially considering that long tail latencies stack on eachother in RAID, so it helps to have drives with essentially zero tail latency. I did a bunch of testing on this back in my PCPer days. RST RAID only adds a few microseconds on top of the 7-10us of Optane (vs. NAND reads running ~50us). AMD RAID is historically worse but they seem to have been improving recently.
Thanks for the response’s guys, i’ll go ahead and try it out then!
Man, I’m jealous about these two 750GB P4800X for £300, especially if it’s for both of them.
Living in Germany, got myself two 375GB P4800X for 140€ each recently, 280€ for both. These things aren’t that cheep here in Germany.
Was thinking about doing a Windows reinstall to Win 10 LTSC with AMD HW RAID 0, but after my testing this definitely won’t work. Looked for PCIe HW RaRAID id Cards, not really worth it.
My P4800X are connected as following on my X570 Aorus Master (rev 1.0, BIOS F37h):
M2A_Socket (CPU) with a M.2 to U.2 Adapter
PCIe x4 (Chipset) to U.2 Adapter
Here are some CrystalDiskMark screenshots (with my Force MP510):
Here are my RAID 0 Array settings in the Bios:
My AMD RAID driver story was horrible, uninstalling was a nightmare, because I used the RAID Installer from AMD’s x570 driver page after installing the driver manually to check the RAIDXpert2 Software.
It replaced all NVMe drivers with the AMD drivers after reboot, which is baaad.
It froze my system after some seconds, safe mode froze even faster. Manged to uninstall by using pnputil as fast as possible, lucky that this worked. DISM /remove-driver didn’t detect the AMD RAID driver from the recovery environment.
Anyway here are the results, first with 9.3.0.296, then with 9.3.2.158 after seeing how bad the performance was.
Tried Win10 SW Raid after uninstalling that mess, here is the result:
So yeah, AMD HW Raid 0 bad, wish Win 10 SW Raid 0 were bootable…
(Anyone want to sell me a P5800X for not thaaat much? 
)
Your final set of images summarizes what I saw tinkering with Optane 905p raid. Almost double the latency, slightly reduced q1t1 performance, and the sustained read write performance doubles.
I had the same experience with VROC RAID 0 with my pair of 960GB Optane 905P drives. I decided to back out on RAIDing them for that reason.
