Do Render Engines use the GPU?

Zoom123 · 11 Dec 2011, 10:25

Hello,

Would upgrading my video card help skethup models to render faster with something like Twilight or Maxwell? Or render engines do their work by using mainly the CPU?

Thanks

Marian · 11 Dec 2011, 11:11

I don't particularly know if Twilight or Maxwell use the GPU but most seem to use only the CPU for rendering though there are renderes that can use one or the other or both like Bunkspeed Shot.
I use Simlab Composer which now uses only the CPU. I upgraded recently my RAM and graphics card and didn't improve rendering times at all.
So you should do a little more research on each renderer and see which can do what you want it to for a reasonable price.

Gaieus · 11 Dec 2011, 11:25

Twilight does not use it ATM (I cannot say anything about Maxwell). Twilight uses the engine of Kerkythea and the developer of Kerkythea is the same as of Thea that will use GPU one day (not yet). So theoretically the technology can one day get into Kerky and then into Twilight, too, but there are too many "if's" here of course.

Zoom123 · 11 Dec 2011, 13:52

Thanks.

Regarding CPU, how much difference would a core i7 2600K make over core i5 2500K when it comes to rendering times?

Similarly, would 16GB of RAM offer a noticeable performance benefit over 8GB of RAM?

notareal · 11 Dec 2011, 15:21

@zoom123 said:

Thanks.

Regarding CPU, how much difference would a core i7 2600K make over core i5 2500K when it comes to rendering times?

Similarly, would 16GB of RAM offer a noticeable performance benefit over 8GB of RAM?

http://www.anandtech.com/bench/Product/287?vs=288
For CPU I'd go with i7, it has 15-30% difference, based on multithreaded cinebench and powray. For RAM I'd take at least 16GB. If you run out of RAM, you basically cannot render no longer, but otherwise 8 to 16GB will not give any speed. To benefit all that RAM you need naturally 64-bit OS and 64-bit renderer. Note, most renderers that run actually inside contexts of SU are 32-bit. If you want 64-bit renderer, it must be outside of SU (data transfers by pipe/file/...). In that case a studio renderer is a good option.

Zoom123 · 12 Dec 2011, 02:37

Thanks. I will start by using something like Twilight or Maxwell for SU on Windows 7. How much RAM will they be able to access?

notareal · 12 Dec 2011, 16:08

I don't know certain for Maxwell for SU, but if it works in contexts of SU, it's limited to max 4GB. Same goes with Twilight. Only 64-bit programs access more RAM (mainly render studios).

Zoom123 · 12 Dec 2011, 21:05

@notareal said:

I don't know certain for Maxwell for SU, but if it works in contexts of SU, it's limited to max 4GB. Same goes with Twilight. Only 64-bit programs access more RAM (mainly render studios).

Thanks. Would something like Twilight that works within Sketchup also limit the CPU, or if I get the i7 2600K instead of the i5 2500K I will get the full 15-30% difference?

Gaieus · 12 Dec 2011, 22:59

No, CPU (and all its cores) can be utilized - at least by Twilight that I know.

brodie · 14 Dec 2011, 22:24

Maxwell does not use GPU at all. It will, however use any and all CPU you throw at it.

How much ram it uses depends on a few things. The biggies are what resolution you render at and how high your polygon count is. Unless I have other software open I usually keep it under 8gb of ram - probably more like 4-6gb. But that depends a lot on what you're doing.

-Brodie

Zoom123 · 16 Dec 2011, 03:14

Thanks. So say an interior scene of a room with several artificial lights and everything that is needed to produce a photorealistic result at a resolution of 1920x1080, could it need more than 8GB? I am not planning to print anything so 1920x1080 is probably the max I will ever need.

brodie · 16 Dec 2011, 05:00

If you're rendering at 1080 directly from SU you'd have to try really hard to get to 8gb. Even then you'd probably have to be running other software in the background to get that high. If I wanted to save a few bucks and was in that situation I might even start with 6gb with the option of buying a little more later if the need arose.

-Brodie

Zoom123 · 16 Dec 2011, 19:22

@unknownuser said:

If you're rendering at 1080 directly from SU you'd have to try really hard to get to 8gb. Even then you'd probably have to be running other software in the background to get that high. If I wanted to save a few bucks and was in that situation I might even start with 6gb with the option of buying a little more later if the need arose.

-Brodie

Thanks Brodie. I think I will go for 8GB then.