Render speed increase with new tech.

[Mattheng]

Am running some movies with 600 frames.

When going from a Mac Book pro with a 2.53 gHz Core 2 Duo and 3 gB of RAM to an iMac with a 2.8gHz i7 8 core with 8 gB of RAM the render time per frame goes from 38 seconds to 21 seconds.

Nice but somehow not as nice as I expected.

Am rendering in Custom Renderworks, no indirect lighting, no HDRI, four independent light sources and everything everything low except environment lighting which is on very high.

Nor sure if the environment lighting needs to be high either

Any idea how much extra grunt is necessary to make things run, say, 4 - 5 times faster which is kind of what I was expecting (8 / 2 * 2.8 / 2.53 = 4.4, never mind the extra RAM...)?

[M5d]

The iMacs only have 4 Physical Cores + 4 Virtual Cores (hyper-threading). The virtual cores only bump the speed of the i7s by about an extra 10 to 15% of a 4 Core machine without hyper-threading. Your equation may not be an accurate way to gauge performance.

Also, I think, the new indirect lighting in Renderworks 2011 is said to perform better than the use of the older ambient light setting.

It could be worth testing the indirect lighting option for speed, if not the quality of the rendering, and turning the ambient light setting off.

[VincentCuclair]

large texture images (ie. +250kB), blur, refraction and reflections also slow down a render.

[Mattheng]

Yeah, but surely that applies equally to both computers...?

The four core point is a valid one.

Indirect lighting is mainly for indoor shots, doesn't really work outdoors (which mine are), you lose all the detail and it is way slower than using ambient lighting.

Can look good in the right places, though. Check out some of Billtheia's posts

Getting rid of the HDRI really speeds things up and you can get pretty close with multiple light sources.

I have measured the times a bit more accurately and it is 38 secs vs 25 secs.

Still way slower than I would have expected.

Should still be around 15 secs at worst..?

Edited July 12, 2011 by Mattheng

[VincentCuclair]

True! Sorry wasn't paying attention........however Core 2 Duo to 8 Core = half the render time sounds about right?!

One thing I've learned over the years when using different CAD apps and buying new hardware.......there are VERY many factors involved that influence render times.......ie.:

- Does the OS use all of the available RAM etc. last year I learned that Windows only allows software to use max 3 Mb Ram even if you have more.....OSX uses 4 MB.

- Do the software packages support all the hardware features? ie. multi core, RAM, etc. etc. usually not. If so what parts ie. Open GL, Render engine etc.

Not so easy and things keep changing:

Important points (as far as I can tell):

OS:

- OS RAM usage?

- OS RAM limits?

Hardware:

- Graphics card

- Processor speed

- Cores

Software:

- (Multi)Core support (what part ie. Drafting, OpenGL, Render engine)

- RAM utilization, virtual memory etc.

- Graphics card utilization

So just comparing one aspect unfortunately doesn't say too much.....

Edited July 12, 2011 by Vincent C