Is VRAM important for Rendering ?

[SH64]

We are building a rendering computer soon & i'd like to know if the video memory is of any improtance for graphics rendering ? do i should look for cards with more VRAM ?

[jolle]

Not AFAIK.
rendering is pretty much only CPU and RAM.

There are some GPU accelerated renderers, like Gelato (http://www.nvidia.com/page/gz_home.html).
But when it comes down to Max or Mayas own renderers, I dont think there is any GPU involvment whatsoever.

Mental Ray seems to have some measure of GPU acceleration, but I dont really know to what extent, and if its used in "regular" use of MR, or if you set up special rendering passes for it.
And in that respect I dont know how VRAM would influence it, seems more like raw GPU power would play in there.

[SH64]

Thanks for your response jolle.
The program we are using is Uniview (http://www.scalingtheuniverse.com/) (DX9 program AFAIK) . we simply record a scene & then render it to frames. after that comes the encoding which i'm sure is CPU dependent.
do you think there isnt any involvment for the GPU in the rendering process ? we dont want to shell for an expensive Quadro for nothing.

[jolle]

You could try emailing the company that makes the software.
Didnt find anything on about it.
But if I were to GUESS I would say a Quadro wouldnt reduce the rendering time.
Unless it captures from a realtime source.

High-performing renderers. Using the same techniques as modern games, Uniview provides state of the art rendering performance and thus smooth motion at all times.
So basicly it uses a realtime rendering like any game does, but you record something like a game demo? (not capturing frames, but translation and rotation data of the objects in the scene, that is then played back at will?)
If your capture process consists of the GPU playing the scene back, rendering every frame (not keeping 1x playspeed and skipping frames), and saving down every frame, THEN I doubt a Quadro would make a difference (since they appear to do the realtime rendering like a game would).

But really, thats just guessing, before investing any money in this sort of thing you should prolly check with the developer about that.

[SH64]

You could try emailing the company that makes the software.
Didnt find anything on about it.
But if I were to GUESS I would say a Quadro wouldnt reduce the rendering time.
Unless it captures from a realtime source.

So basicly it uses a realtime rendering like any game does, but you record something like a game demo? (not capturing frames, but translation and rotation data of the objects in the scene, that is then played back at will?)
If your capture process consists of the GPU playing the scene back, rendering every frame (not keeping 1x playspeed and skipping frames), and saving down every frame, THEN I doubt a Quadro would make a difference (since they appear to do the realtime rendering like a game would).

But really, thats just guessing, before investing any money in this sort of thing you should prolly check with the developer about that.
Yep you seem to be correct. i did e-mail the dev yesterday & i've got the minimum/recommend reqs list. the program dosent seem to need a quadro.
they recommend a C2D 2.4Ghz or above , 2GB RAM & a SM3.0 capable card with 512MB VRAM. (SM3.0 card is a min req aswell)

for optimal performance they recommend a 7900 class or above - up to the 8800GTX. so most likely i'll be going for a C2QX Processor & a 8800GTX & scratch off the Xeon/Quadro setup.
(the list also mentioned a 7700GT & 7700GTX .. is there such a card ?? :wtf:)

[Toss3]

Nope don't think vram would affect rendering times in any way. I believe the memory is there in order to allow you to preview and create huge maps and scenes without stuttering and slowdowns. :)

[LilSoapyShimpty]

Vram only effects modeling and animation as GPU is only used for Viewport and viewport is OpenGL. If its a render machine spend money on CPU's first. Unless your render applications is written to use the GPU also like Gelato. Which most are not.

What makes a difference on rendering in 99% of the time is CPU MHz, FSB, # of Cores, RAM, RAM FSB, and 64bit OS.

e.g ran several tests on my machine over the weekend here are the results may help you make your decision

Stock config .no OCing

2.4GHz Quad Core Q6600 1066 FSB
4GB DDR2 Memory 800MHz
OS 32bit vs 64bit.

Tested in Cinebench R10 32bit and 64bit

Below is stock above components in Vista 32bit

Single Core Render - 2414 - Render time was 5 min 45 sec.
All 4 Cores - 8359 - Render time was 1 min 24 sec.
Perf Ratio (1 core vs. 4 cores) - 3.46x
GPU OpenGL - 4082

Below is stock above components in Vista 64bit

Single Core Render - 2731 Render time was 5 min 42 sec.
All 4 Cores - 9729 - Render time was 1 min 20 sec.
Perf Ratio - 3.56x
GPU OpenGL -4183

So you can see above 64 made a minor difference this is rendering at 800x600. Give you an idea of time that 64bit difference translates into 2 -4 seconds faster than 32bit.

OCed components 29% CPU OCed RAM %30

Q6600 (2.4GHz Stock) OCed to 3.1Ghz
4GB RAM (800MHz Stock) OCed to 1071Mhz
FX4600 Stock No OC

Single Core Render - 3538 - Render time was 5 min 29 sec.
All 4 Cores - 12169 - Render time was 1 min. 10 sec.
Perf Ratio - 3.44x
GPU OpenGL - 5207

The GPU's OpenGL and DX10 performance is directly dependant on your FSB and your RAM FSB.

My friend ran a similar test on an 8800GTX he has the same config as me but with a GeForce card instead. He had to OC to 3.9 GHz on his CPU 1066FSB on his RAM and 1700 MHZ FSB on CPU to get the same 5200 score as me. I will illustrate that below.

Lastly i wanted to see if I could crank up my GPU OpenGL perf.

Last test was done with x7 multi at 429MHz. Which came out to a 1700FSB for the CPU due to this I have to drop to 2.8GHz to run stable. RAM still OCed to 1071. This time GPU OCed from 600MHz to 700MHz and GPU vRAM from 700MHz to 750MHz.

CPU stores drop by 300 or so points in rendering due to drop in CPU core speed from 3.1 to 2.8GHz.

GPU score - 5793

So hopefully that gives you an idea of whats important in rendering from a hardware perspective.

[SH64]

Thanks for the info LilSoapy!

[LilSoapyShimpty]

Anytime :)