Shroud for AMD Instinct MI50 workstation GPU and BA10033B12H BBQ blower fan

Instinct MI50 BBQ blower fan shroud JSCAD share link

There is a new sticky “Radeon Instinct MI50” thread on mersenneforum.org (registering needed for access):
https://www.mersenneforum.org/node/1072920
Used Radeon [pro] vii GPU prices are typically >250 USD. Used Instinct MI50 GPUs are available much cheaper and with big stocks, initial posting of thread has links to such sellers.


AMD Instinct MI50 is the fastest among AMD's (now) cheap Vega20 GPUs (the others are Radeon vii and Radeon pro vii; I own all three) with high memory bandwidth of 1.02TB/s and 6.705TFLOPs FP64 (double precision). Because it is a workstation GPU, unlike both other models it does not come with a fan.

 

Until now I used a U-turn shroud that I got when I won a Nvidia K20X GPU on ebay. Despite high air speeds at the fan, at bracket air speeds were measured between 3.1m/s and 3.2m/s only:

The new shroud is fixated with three M3x10mm truss head screws:

I knew that I bought the special China version of the Instinct MI50 first (I bought it over ebay from Hong Kong), and the top label confirms that. My “normal” MI50 with beige shroud I bought later has a different type of label.

 
On one of the photos you can see that the fan is powered with a small connector from a PSU Molex connector with 12V all the time. Molex to fan adapter cables are available eg. on amazon. The 1.32A 12V fan consumes only 15.84W, tiny compared to GPU power draw. The safe operation of GPU is more important to me, while doing multi-day PRP proofs for numbers with millions of decimal digits [ ETA for 100million decimal digit number with that GPU is 7d 2h, interesting for this price money ;-) ]

As you can hear in the youtube videos, that BA10033B12H BBQ blower fan (eg. on ebay) is very loud.
No problem for me as that PC is located in basement computing center.
This video is mostly demonstrating the loudness level at different distances.
Sound level meter showed 53 dBA at start and 69 dBA closest to case:
https://www.youtube.com/watch?v=pXF-pmr4TWQ

Here is air speed profile of the shroud (14.5m/s maximally in middle):
https://www.youtube.com/watch?v=pCeFW2Y_JUk

And here is air speed profile at GPU bracket, between 6.1m/s and 3.8m/s now:
https://www.youtube.com/watch?v=5IA-y-lC6zk

A cool (in the word meaning) consequence is that now GPU can run with default power cap of 250W while not reaching critical Junction temperature of 100°C. With the U-turn shroud I had to cap GPU power at 200W to keep temperature at most 93°C:
https://www.mersenneforum.org/node/1064787?p=1070093#post1070093
With reduced power gpuowl processing worsened from 522µs/iteration to 540µs/iteration.

With new shroud I aborted same test run as in linked posting after 6 hours.
Power consumed by GPU was in 242..248W range.
Iteration time did not decline:

hermann@7600x:~$ sed "s/^M/\n/g" gpuowl-v7.2-131-gca22dce-ubuntu/nohup.out | grep check | cut -b131-135 | sed "s/^[ ]*//g" | cut -b-3 | sort | uniq -c
     1 521
  3852 522
    10 523
   124 533
     6 534
     1 535
hermann@7600x:~$

 

And best, Junction temperature never got above 89°C(!) with the much better air speed:


hermann@7600x:~$ echo "..." && cut -f3 -d\  nohup.out | sort | uniq -c | tail
...
   119 80000
   117 81000
   159 82000
   170 83000
   258 84000
   354 85000
   607 86000
  2328 87000
 16377 88000
   980 89000
hermann@7600x:~$

 

Attached are the 1:42h Prusa MINI+ GCODE file as well as the STL model it is based on.
You can open the model in your browser and modify and/or export in different format:
Instinct MI50 BBQ blower fan shroud JSCAD share link

The attached photos with sky blue shroud show a beta version of the model, where the model was improved to make removal of the two 8pin PCIE connectors from the GPU easier in final light green model. One of the beta photos shows that solution fits into small PC case, but then needs to cut some metal with nipper pliers. The other shows that solution does fit nicely into bigger case. Unfortunately both PCs do not have a gen4 x16 PCIE slot, and the MI50 GPU only works in a gen4 x16 slot after I flashed MI50 bios onto it (it had Radeon pro vii bios when I bought it):
https://www.mersenneforum.org/node/1070049

The other photos show the GPU with new light green shroud in PC with gen4 x16 slot. Even here I had to cut the bottom right metal of fan opening a bit to make solution fit. I did insert card with screwed shroud into PC first. Then I did insert blower fan from front.

Inserting the fan is a bit tight and needs some pressure. But with this no superglue to fixate (as originally planned) is needed. 

The shroud allowed to keep junction temperature at most 88°C (critical is 100°C) in run stopped after 7 hours, with new gpuowl minimal duration time of 468µs/iter(!) obtained by overclocking HBM2 memory with 1200MHz (default 1000MHz):
https://www.mersenneforum.org/node/1064787?p=1072342#post1072342

I opened a used Instinct MI50 bought newly to see whether it has dust inside, and it had not (6 screws for cover, 4 screws for bracket, after I had seen this video).

One Instinct MI50 is nice, but four are nicer (one inside PC with 2000W PSU) — 26.82 TFLOPs FP64 in one PC. All four MI50s have same BBQ blower fan and this shroud. All 3Dprinted parts are in my GPU stuff collection. Details on my modifications on mining rig base are in my Make of that 3D model.