Author Topic: Dual cpu speed problems  (Read 4675 times)

2018-05-20, 23:02:59


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Hi all, I have two CPUs - Intel xeon e5-2698v4 es (each has 20 cores \ 40 threads) on the motherboard asus z10pe-d16ws.

In the corona render benchmark, v-ray test, cinebench r15, everything is fine, the results are as they should be, in 3dmax18 + corona render too all ok.

In c4d I manually set how many threads are used for rendering, and as soon as I begin to use the threads of the second processor (in the settings 41 threads , which is 40 threads of the first processor, and 1 thread of the second processor) starts rendering speed gets worse, and the more threads of the second processor are used, the rendering speed becomes worse.

After spending about a month looking for the source of the problem, I noticed that you need to load all the textures through the corona bitmap (it turns out like a "crutch"?), Then with the speed all ok ... But the corona bitmap does not respond to the transformation (scale, rotation) through the projector or the layer

2021-07-31, 20:22:58
Reply #1


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I think I have similar problem than you. Did you solve it?
I have 2 computers one with the same motherboard as you, with 2 e5-2696v4 (88 threats). And my other computer is a e5-2678v3 (24 threats)

At several benchmarks, the dual system is more than 3 times powerfull than the single cpu computer (cinebenchR15, cinebenchR20, cinebenchR23, coronabenchmark 1.3...)

But when I'm rendering with corona DR (3dsmax 2021.3 and corona 6.2), dual system makes only 1.1~1.2 times more passes than the single cpu system... How it can be possible?
At first time, I though I had LAN issues, but doesn't matter wich computer is slaving or is the main. The result is the same. Also, if I put the same scene at the same time in each computer to render. Dual system is only 1.1~1.2 faster than the single one... So, what is going on?!

When dual system is rendering, 88 threats are full load (100%) all the time without any drop... So reading at you, I guess corona is not handling properly dual system computers. I guess, corona is rendering with both CPUs in PARALLEL instead of in SERIAL (adding passes). Cos something is missing or failing at corona programing code... And that makes sense why if you deactivate one cpu in the dual system, the performance rise a bit... Cos again, is just a guess, I think both cpus are fighting to render the same pass at same time, reading the same info at RAM at same time. But at the end, only 1 CPU passes are counting...

I made some test with vray also, and results are more or less expected (dual system rendering 3 times more buckets than single cpu)

So, anyone can send some light to this problem?