quad core

[nomeradona_cg]

hi damien et al,

i just bought a new computer with 2Quad CPU @2.4G, when im rendering i found out in the window task manager that its just usign 30-40% of the CPU, why like that? can you please explain.

[dalomar_cg]

Re: quad core

It depends on what part of the process is being run. There are a few actions that require single threading, mainly merging and filtering the LC pass. Also, the LC calculation is split up into whats called phases, with each phase effectively being a thread. If you have that set to a number less then the number of available threads, then you'll have unused resources. Its good to note the more phases will require a longer merging time for LC. On my dual-dual core (4 threads basically) at home, my general test settings have 3 phases for LC because the time gained by having the 4th phases made merging take a little longer. This is just for tests though as higher quality renderings the 4th phase is worth the extra merging time.

Outside of reading/loading files, the LC stuff is the only real single threaded action within V-Ray of any significance.

[nomeradona_cg]

Re: quad core

thanks damien for your reply. ok i will observe more this thing.

[dalomar_cg]

Re: quad core

Nomer,

Now that I look over your post, I noticed that you have a dual quad. I thought you just had a quad core. So with that in mind its good to mention that the default number of phases is 4, so without changing a thing your machine will only calculate LC @50%. You're probably going to need to do some tests for LC phases<->Merge time issue. With 8 phases merging can be quite a task, so I doubt that using all 8 for LC will be the fastest (only for very complex situations will 8 threads be needed). This is probably even more the case with a 2.4g proc as merging relies on clock speed as opposed to parallelism. With a 3.2g proc you may be able to add those extra threads, but those 3.2 quads are a pretty penny.

[thomthom]

Re: quad core

Dual Quad... *dreams*

[40th]

Re: quad core

Sorry for the ignorance, but is Intel(R) Core(TM)2 Quad CPU the same as Dual Quad?

[stefanq]

Re: quad core

Heard this kind of problems, if you run v-ray on a "virtual" machine. On my Core 2 Quad, I get 4 buckets, and the processor it's 100% used when I render.

[thomthom]

Re: quad core

No, Intel(R) Core(TM)2 Quad CPU is not Dual Quad.

Intel(R) Core(TM)2 Quad CPU is a Core 2 type of processor. They come as either Dual or Quad. Intel(R) Core(TM)2 Quad CPU has one processor chip with four processor cores.

A Dual Quad core is two processor chips with each four cores totalling in eight cores.

[40th]

Re: quad core

WOW that's got to be pricy machine
Thanks Thom for clearing that up.