PCIe v4 NVME drive - why so slow?

Quartz · 26 Jul 2020 at 16:53

Sabrent are launching a 4 TB PCIe v4 NVME drive. The read speed is 40% better than v3 but the write speed is only marginally better:

Why is this? Why aren't both - particularly read, near double?

EsaT · 26 Jul 2020 at 18:33

You shouldn't get stuck on that part:
Rocket Q is QLC drive.
So its actual native uncached/unbuffered write speed isn't even one tenth of advertised.

Quartz · 26 Jul 2020 at 19:44

That depends upon the size of the cache and the speed with which the cache controller can write to the rest. For instance Linus Tech Tips looked at an 8 TB NVME drive and saw no drop in performance long after the cache should have been filled.

Gray2233 · 26 Jul 2020 at 19:56

Sabrent's current TLC 4.0 drive has 5000 MB/s read and 4400 MB/s write for reference.

Just because we have access to higher bandwidth doesn't mean the hardware we use is immediately going to double or triple in performance, it'll take time for things to build up.

I remember reading about some 4.0 drives throttling due to heat for example, there's definitely some hurdles to get over.