NVME speed not up to par

[Trypt]

Hi guys. I think it's in my sig (I will check and update if not), but I have a 1GB SX8200 Pro as my OS and downloads drive in the CPU nvme lane slot on the mobo, and the GAMIX 2GB (same chip I think, just comes with the heatsink) on the bottom slot as my game install drive.

I won't post the pics as it's a simple explanation, but I get the advertised speed for both when doing a test, the test everyone uses, around 3GB/s read and almost that in write. No matter what's happening on my system, I get top speeds and all the numbers match what I see on reviewers videos.

However, when transferring files from one to the other, it maxes out at 1.2GB/s, like it's capped, it goes to that right away and stays there for the duration, whether I'm sending 50GB of a single file, or 50 1GB files. Now, this speed is still very good and I don't mind really, I just wonder if there's something going on or if anyone may have suggestions. I doubt it's a bios setting as the test says I get full speeds but who knows.

Oh, part 2, while I'm at it, for the virtual file, I had it set for windows managed C drive only, but when I noticed that I set it to windows managed for both drives (The 6GB spinner is disabled for virtual memory). Is that good? Should I use both, windows managed, or do like the old days and set a min/max?

 

[Ben333]

Only thing I can think of is that maybe the benchmarks are hitting more of the DRAM cache in the SSDs and thus performing much faster, because the transfers are so small. 1 Gigabyte per second is extremely fast. That is the max throughput of 10gb lan. (ten giga-bit)

 

[dejo]

I think that the sx8200 has a small SLC cache area, which then puts you at the native speed of the nand

 

[Trypt]

So that's normal max speed then for those drives? I'm happy regardless, and got them both for a good price, but from all the reviews I've seen, they are on par with the SN750 black from WD for example, even the Samsung 970. Or are you saying that with those drives I'd actually see 3GB/s transfers between the drives.

Like I said, I copy from the 1TB drive to the 2TB drive or vice-versa, they are each in their own M.2 slot on the x570 mobo, each getting the full pci-e lanes.

I guess there's nothing I can do but enjoy 1.2GB/s.

 

[dejo]

the sn750 native nand speed is around 1.4 or 1.5gb/s

 

[Ben333]

I have one SN750 and I get a max of about 3 GB/sec (in benchmarks) but I do not have a second drive nearly that fast to test a large file copy. Suppose I could do some testing between my SSD and a RAM disk.

 

[wagex]

I wonder if the drives aren't sharing a bus... it would make sense why disk to disk you are getting a hair under half benchmarked speeds.

 

[Ben333]

I wonder if the drives aren't sharing a bus... it would make sense why disk to disk you are getting a hair under half benchmarked speeds.

Good suggestion, but these are NVME SSDs so they would both have their own independent pci express lanes.

 

[Trypt]

OMG, I feel like an idiot a bit, turns out that I'm actually getting advertised speed according to reviews, with bursts being in the 3GB/s but indeed the sustained write for these drives, including SN750, is about 1.2GB/s to 1.4GB/s, all gen 3 drives short of the 970pro are in this range, with the latter getting up to 2GB/s sustained but even it cannot do that forever.

Thanks anyway, I don't know what reviews I was checking before but clearly not deep enough.