Using a crypto mining rig for Iray

onesandwichshort

Has anyone else ever “accidentally” won an auction on eBay?

I was watching eBay as the crypto market declined late last year and dreaming about using a rig for Iray rendering in Daz. Eventually I came across an auction for a 12 card rig with 1060 GTX 6gb cards.

I bid the opening on a crypto miner thinking that there was no way that it would go for the minimum bid. I was the only bidder. Oops!

It has been a couple months since I won the auction and I now have everything working with Daz Studio. There are a few things that are not immediately obvious in using a crypto machine for Iray rendering.

 

The first is that mining rigs do not ship well.

Packaging material jammed in to help the video cards travel safely weakened riser card connectors causing intermittent problems. I ended up having to replace the usb/pci riser cards to get everything working in Windows.

I recommend using Ver008S or VER009S as they have led indicators to help figure out where connection problems are occurring. From a performance standpoint there is not a difference between any of the risers, just the types of power connectors and the led indicators.

 

Next, the processor has to have available threads to handle the data traffic to the video cards.

On my early test renders, only four of the video cards had spinning fans. Since I was rendering a simple single figure animation and running into other bottlenecks (more on this below) I didn’t think too much about it.  After a second test render I decided to check the error log and saw this message:

IRAY   rend warn : Cannot use CUDA [devices 4-12] (GeForce GTX 1060 6GB). Not enough CPU threads available.

The rig originally came with a two core Intel Celeron processor. For mining this is fine but I figured I would need a bit more for Daz and picked up a four core I5. In the end the I5 was only able to transfer textures and other data to four of the cards. This meant that the max number of used video cards depends on the number of threads the CPU is capable of.  I have replaced the CPU with an I7 6700k which is the top of the line that the crypto mining motherboard is capable of using. This is true of all the crypto boards I have seen.

The new CPU is 4 core 8 threads but the speed of the processor, at least on my simple test scene, allow the machine to use 12 video cards.  I have not yet tested to see if a more complex scene will drop the number of cards Daz will use.

 

Last, data transfer and file creation overhead limit seem to the maximum file creation to roughly 2 images per minute.

Well that killed my initial goal of being able to render a short for 48-hour film contests. For my bigger dream of rendering out shorts and perhaps eventually a feature length movie, this is probably going to be okay as other production needs will keep me busy.

Overall I am glad that I won the auction, it was just sooner than I would have planned.

onesandwichshort

Here is a link to the animation I used as a test of the system. In the end I had 3 machines rendering out portions of the animation and one of them used the beta of 4.11. The portion the machine with the beta version rendered out gives a slight color shift in the clothes. All the machines hit the ~ 2 images per minute top speed.

Frederick Douglass render test: https://youtu.be/iRrAOjy3X6M

rrward

I was thinking about doing something like this. The logistics looked like more than I wanted to deal with so I went with two monster cards rather than lots of weaker cards (I was briefly flirting with the idea of six RTX 2080ti's, but had to remind myself that I don'r have that many kidneys to sell.)