MP 7,1 Mac Pro 7.1 nvme slowdown with sonnet pcie card? Or normal?

[rondocap]

2019 Mac Pro with the newer version of the sonnet m.2 pcie 4x4 card. Drives start fast in large file transfers, but then slow down A lot. Pcie lanes seem ok, Vega ii gpu and io card only.

card is in the x16 5th slot

1. 4tb inland nvme platinum
2. 2tb adata x8200 nvme
3. 1tb Samsung 980 pro
4. 1tb Samsung 980

any idea? the apple ssd stays on Max speed with large transfers or benchmarks.

1. Is it the cache or a tlc issue? The Samsung pro should be fastest
2. Possible pcie speed issue?

 

[JJL2026]

I didn’t understand a word you said. Was it shorthand, or names of computer internals that just are way above me?

 

[rondocap]

I didn’t understand a word you said. Was it shorthand, or names of computer internals that just are way above me?

nvme drives are slowing down with large file transfers

 

[tsialex]

All TLC NAND drives will slow down the throughput to real rate of the TLC NAND after the SLC cache is full. You can do nothing about that besides getting a drive with bigger caches/better controllers.

BTW, Samsung 980 PRO is TLC while the 970 PRO was MLC and the drop from the SLC cache to the MLC NAND was almost imperceptible in real life with the previous generation.

 

[rondocap]

All TLC NAND drives will slow down the throughput to real rate of the TLC NAND after the SLC cache is full. You can do nothing about that besides getting a drive with bigger caches/better controllers.

BTW, Samsung 980 PRO is TLC while the 970 PRO was MLC and the drop from the SLC cache to the MLC NAND was almost imperceptible in real life with the previous generation.

What are the drives you’d recommend that keep the speed as high as possible for large transfers? 970 pro?

 

[tsialex]

What are the drives you’d recommend that keep the speed as high as possible for large transfers? 970 pro?

970 PRO is one of the few M.2 blades that was made from MLC, is Mac compatible and is probably the only one that still easily found.

 

[mBox]

970 PRO is one of the few M.2 blades that was made from MLC, is Mac compatible and is probably the only one that still easily found.

I have a few of these in my 7, 1.
I am getting on avg 5100 r/w.
Is this normal?
And how large of a file do I need to test this slow down at the end issue?
Is there an app I can just use?

Thanks in advance.

 

[tsialex]

I have a few of these in my 7, 1.
I am getting on avg 5100 r/w.
Is this normal?
And how large of a file do I need to test this slow down at the end issue?
Is there an app I can just use?

Thanks in advance.

Any file transfer bigger than the SLC caches will throttle down to the real TLC NAND throughput, open the data sheet of your blade to know the size of it. No benchmark tool needed, even a big enough Finder transfer will show it.