Blackmagic Forum

I see this has been discussed, but here are my details:

Mac Pro 3,1 | 2x 2.8GHz | OSX Mountain Lion | 16GB RAM | GT120+GTX580

The system works fine for the most part until I go to render out the footage. I am rendering Sony SR-SQ 1080p444 to DNxHD36 and small QT Proxies. I get something like 5-23 frames per second; it fluctuates constantly. The main reason I purchased the full version of Resolve and installed 2 graphics cards was so I could get super fast rendering speeds. In this configuration I am only getting speeds as fast as I was getting when I only had one, non-CUDA card installed. I believe it's actually a little slower! What am I doing wrong? Dwaine Maggart, are you there?

Thanks,
Aaron

Are you rendering to and from the same drive? Is it an internal drive? Sounds like you might be hitting some disk performance issues.

Source has been my desktop. Destination is an internal RAID 0.

There are many potential reasons.
Lets start with; you have a relatively to todays motherboard and CPUs, low motherboard bandwidth and slow CPUs and give you are making two compressed renders in one pass, the CPUs are likely busy.. can you verify their % use with activity monitor?
Try doing a BMD disk speed test on the desktop (your source) and raid 0 (your destination).
Try then without the GT120 installed, just using the 580.
If you render one output, say the DNxHD, whats the speed? Then the other, QT something non defined...
What is the actual version of Resolve, CUDA and MLion?
Peter

I'm doing each transcode in it's own pass, not 2 at once.

CPU
% user : 55-72
% System: 10-15

BMD speed test: 185 MBps read and 190 write

With just the 580 working, Resolve states "CUDA drivers are not installed", then crashes. Restart it and it says "your set up is not good for real-time performance" Then when I render out DNxHD36 it still gives about 5-20 frames per sec. WHen I do ProRes proxy it gives me about 13-23 fps.
I should state that each of the clips in my timeline have a correction added form a .cdl. When I remove the correction it speeds up the Pro Res by about 5 fps a sec, but nothing for the DNxHD36.

Resolve version: 9.0.0.087
CUDA Driver Version: 5.0.37
GPU Driver Version: 8.0.61 295.30.20f02
MLion: 10.8.2

Your main problem with the Render Speed is the Mac Pro 3,1. The internal PCIe buses are not fast enough to pass the data to the GPU's. We had the same problem until we upgraded to a Mac Pro 5,1 and now we Render at a minimum of three times real time to DNx36. Note no hardware was updated except the Mac Pro and now Rendering is not so painful. Thanks

This is definitely not the news I wanted to hear. I sincerely hope there is something that I can do. I have spent a lot of money trying to get this thing to render fast.

I spent a whole day testing different Configurations, Video Cards and even an Expansion Chassis with three GPU's with no improvement until we upgraded the Mac Pro. Thanks

What if I were to upgrade to 32GB of Ram, could that help matters?

Sorry but I tried extra RAM as well and it didn't help. Besides good RAM for those machines is very expensive. Check out the OWC site, I tried cheaper RAM a couple of times and had nothing but grief. Thanks

I will say that I should have done my homework more thoroughly. But if this is known by BMD to be an issue, they should have put it in the configuration guide.