6,1 - Installed Samsung 970 Pro 1TB, is there a simple reason why I dont see a huge transfer speed?

Messy

macrumors 6502
Original poster
Sep 5, 2010
426
12
https://imgur.com/sLGTm7Z

^ Speed

Any reason why I don't see even close to the rated speed that these drives can put out? I'm sure there's a simple explanation presumably something to do with lanes and such.

If someone could just clear that up for me I'd be grateful. Seems a shame to have such a high spec drive and not be able to take advantage of the speed.
 

tsialex

macrumors G3
Jun 13, 2016
8,169
8,720
https://imgur.com/sLGTm7Z

^ Speed

Any reason why I don't see even close to the rated speed that these drives can put out? I'm sure there's a simple explanation presumably something to do with lanes and such.

If someone could just clear that up for me I'd be grateful. Seems a shame to have such a high spec drive and not be able to take advantage of the speed.
You are limited with PCIe 2.0 speeds and just 4 lanes, so maximum throughput possible after overhead is just around 1500MB/s.

Look here:

Screen Shot 2019-03-08 at 13.14.37.png


You can get the full diagram here: Did someone say block diagram?
 

Messy

macrumors 6502
Original poster
Sep 5, 2010
426
12
Cheers, as I suspected. What a shame, that's quite the way to cripple the speed.
 

saulinpa

macrumors 6502a
Jun 15, 2008
936
394
It was state of the art 6 years ago. One of many reasons people are pushing for a refreshed MP.
 

Messy

macrumors 6502
Original poster
Sep 5, 2010
426
12
So a bit of an update, i'm now getting very poor speeds.

Anyone shed any light on this?

https://i.imgur.com/JEVNCxr.png


[doublepost=1555425704][/doublepost]Hmm, am I right in seeing that this is only using 2 lanes now?

 

Messy

macrumors 6502
Original poster
Sep 5, 2010
426
12
Link speed it's x2 not x4. What pcie adapter do you use? Todoay, I installed my 970 evo 1TB and I'm getting 1500+ speeds on both read and writing. I use the Aqua Computer kryoM.2 evo PCIe 3.0 x 4, adapter.

See this: https://forums.macrumors.com/threads/blade-ssds-nvme-ahci.2146725/

Yes I can see it's x2, not x4 which is why it's slow.

I have been using https://www.amazon.co.uk/gp/product/B01CWWAENG/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

In my OP it was running at full x4 speed.
[doublepost=1555427419][/doublepost]
Link speed it's x2 not x4. What pcie adapter do you use? Todoay, I installed my 970 evo 1TB and I'm getting 1500+ speeds on both read and writing. I use the Aqua Computer kryoM.2 evo PCIe 3.0 x 4, adapter.

See this: https://forums.macrumors.com/threads/blade-ssds-nvme-ahci.2146725/
Also... that's not on a 6,1 is it?
 

tsialex

macrumors G3
Jun 13, 2016
8,169
8,720
@tsialex any ideas on this, gone from x4 to x2, no change in setup.

  1. Bad connection on the adapter connector, clean it and check for oxidation.
  2. Bad connection on the GPU, test with the original Apple SSD.
  3. Defective adapter, check with a new adapter.
  4. Defective M.2 blade, test the 970 Pro with another PC/MP5,1 that don’t need the Apple M.2 to standard M.2 adapter.
 

Messy

macrumors 6502
Original poster
Sep 5, 2010
426
12
  1. Bad connection on the adapter connector, clean it and check for oxidation.
  2. Bad connection on the GPU, test with the original Apple SSD.
  3. Defective adapter, check with a new adapter.
  4. Defective M.2 blade, test the 970 Pro with another PC/MP5,1 that don’t need the Apple M.2 to standard M.2 adapter.

Well well well, very strange.

I tore down the Mac, removed the PSU, both graphics cards, removed the RAM and SSD and then cleaned everything out using a can of air and reassembled...

Now I have x4 speed! It's likely the Chinese Sintech adapter I would think as everything else just sits there not doing much.

 
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