Adobe Blog by Karl Soule
Something I wanted to share for all you “build-it-yourself” users. Recently, I helped a customer build out a really beefy system – 16 physical cores, plus hyperthreading, 24 GB of RAM, Quadro 5000, etc.
The system wasn’t rendering well at all. Bringing up the task manager was showing each processor only hitting about 19% – 20%. My MacBook Pro was actually handling the same tasks MUCH faster.
This was a classic case of Processor RAM Starvation. With Hyperthreading turned on, the system was showing 32 processors, and there wasn’t enough RAM to drive all those processors! Some processors had to wait for RAM to free up, and the processors that finished their calculations had to wait for THOSE processors to catch up. It’s a really bad state to be in. With multiple CPU’s, everything has to happen in parallel, so when some threads take longer to finish, everything comes to a screeching halt.
I turned off hyperthreading, and suddenly, the system started to just FLY – all the CPUs were being utilized effectively and roughly equally. Render times were over 10-20x faster.
I can’t stress enough the need to ‘balance’ the system to get proper performance. There’s never a danger of having “Too much RAM”, but too many processors is not necessarily a good thing! read more...Note: Videoguys recommends 2GB per CPU core. So for a Quad Core i7 with Hyperthreading, we recommend 4 (cores) x2 (hyperthreading) x 2 (GB per core) = 16GB or RAM or more. For a dual Quad Core XEON System we would recommend 2 (processors) x 4 (cores) x2 (hyperthreading) x 2 (GB per core)= 32GB or more.