CUDA vs. light cache - for fast preview

[bertjow1]

Hello,

 

 

I was wondering what would be better for fast render preview, GF 560 TI and use it 768 CUDA Cores or put more ram for light cache.

 

I never used GPU for rendering that's why my knowledge about it is almost none.. and I am not sure if game card as GF will do, or it will burn... because of the temperature.

http://www.geforce.com/hardware/desktop-gpus/geforce-gtx-650ti/specifications

 

Pro cards are to expensive but at least they are stable and they don't take 300W..

 

my hardware - i7-3820, Asus P9X79, 16 Gb ram

 

 

 

What would be better choice?

[Francisco Penaloza]

This depends of many things actually, what you mean with "Fast previews" fast like a second a rendering? or fast as one minute for a large scene with millions of polygons? and what resolution are we talking about?

To me GPU rendering in VRay is useful sometimes to find the correct sun direction, I get real time interaction with minimal size scene, and no materials, it is one of my first step before I go deep in to the scene, once everything is loaded, there is no way that I can fit the whole scene in my GPU.

If you low the Irr and Light Cache values a about 600 pix wide you can get really fast previews, even with brute force with 6 or 8 samples render quite fast.

[bertjow1]

yes, exactly as you said, I need it to make some test wth the sun positions - generally with the lights in the scene, it's always faster if you do it in real time than waiting as long as light cache will give me some idea of how it looks.

Also to make some tests with the colour palette in the scene and materials - spectaculars, glossiness and so on.

Actually I didn't even counting that i might render all scene by GPU (it is even possible.. to get the same quality by GPU than CPU..) for sure not by using something like GTX 560 TI.

 

About the resolutions I don't know... i have no experience with GPU so I have no idea what I can afford.

When I use CPU for the test renders i use half resolution of the final scene (to check lighting and GI quality), when I test materials i go even lower to reduce time. - or render some regions, so typical

 

final scene is A3 200dpi so we talking about something like 3400x2400 pix.