What might be up?

[cg_Butler]

I've recently been upgraded at work to a new "faster" computer. Spec as follows.

 

32GB RAM

2 x AMD Opteron 6282 SE 2.60GHz 32 cores in total

64-bit Windows 7

3dsmax

VRay 1.5

 

So. It should arguably be one of the fastest machines on our network, but renders any file slower than most of the other machines that are 4-5 years old. Dual Quad core (8 CPU's) machines with 24GB RAM. It renders roughly the same frame times as a dual dual core (4 CPU's) machine that has 8GB RAM, as we have a few of those also.

 

So, I feel, there's something up with my machine and thought i'd ask all you tech bods if you could come up with some potential reasons to trouble shoot. Would it be the simple fact that per core my machine has less RAM available to render, so is struggling with large files with lots of dynamic memory?

 

Or something more sinister like a dodgy RAM stick, processor or core?

 

Your thoughts please.

 

Cheers in advance.

[John Dollus]

when you look at the performance tab in the task manager during rendering, what do you see? can you post a screencap?

[Stephen Thomas]

Memtest is a good little program for sussing out any dodgy RAM sticks: http://www.softpedia.com/get/Tweak/Memory-Tweak/MemTest.shtml

[cg_Butler]

Ah yes I can. I did do one but forgot to save it! I got stuck in to my workload. I will attatch to this as an update. In the meant time here is an explanation of it.

 

This file in particular is very memory intensive. A lot of proxies scattered using multiscatter. It seems like each core in constantly loading and unloading so isn't flat lining at maximum speed if you know what i mean? The graph fluctuates constantly for most of the cores. My machine is using almost 30GB RAM for 3dmax but that is shared over 32 cored so they've less than a gb each.

[Stephen Thomas]

Have you checked what your dynamic memory limit is set to? This is a useful tool for calculating the optimal value for a given amount of RAM: http://www.cgpinoy.org/t22366-vray-dynamic-memory-limit-calculator

[Stephen Thomas]

Does vray actually divide available RAM per core?

[cg_Butler]

Yep. For this job it is 10000. But i've tried it on 25000 and it's no different on my machine.

[cg_Butler]

Quote from the help page.....

 

Dynamic memory limit - the total RAM limit for the dynamic raycasters. Note that the memory pool is shared between the different rendering threads. Therefore, if geometry needs to be unloaded and loaded too often, the threads must wait for each other and the rendering performance will suffer.

[Dimitris Tolios]

Does vray actually divide available RAM per core?

 

If it is true, it is not a VRay limitation, it is probably a G34 socket limitation (i.e. the RAM split is happening @ hardware level).

[artmaknev]

I used Dynamic memory before and render times were extremely slow, but static was crashing the max, nothing seemed to work, I had to go and spent entire day optimizing the scene... not sure why 32 core PC renders at the speed of 8core, very strange, the only thing I can think of is because CPU clock speed is lower but it should be taking longer to render than an 8 core!