recommended RAM for render box?

[coremelt]

Hi, I'm just looking at specs for a render machine that I'll buy in the next two weeks.  I was looking to build a system using a 6 Core i7 3930k Intel Extreme processor and Asus P9X79 motherboard.

RAM is cheap, will Terragen rendering benefit from 32GB or is 16GB going to be enough?

[Oshyan]

It really depends on your scene complexity and render resolution. The more cores/threads you use, the higher your memory use, so that's one aspect. With a 6 core/12 thread machine like the 3930, you'll be using 1200MB for the subdivision cache alone (on the Advanced tab of the renderer, though the automatic settings should take care of this). At resolutions below 1080p, the memory use contribution from the image buffers themselves is probably not tremendous (when considered in the context of a 16GB system), but above that it starts to become more significant, especially with higher AA settings. Large or multiple objects and object texture files also contribute greatly to memory use. A high poly object will have a bigger impact than a lower poly object with lots of instances. Big texture maps are some of the greatest memory hogs of all.

So in general more is always better, of course, and if you are rendering very complex scenes at high resolution, it's possible you could need 32GB. However if TG2 is all the system will be doing, and you won't be rendering at say 4k, then I think 16GB would be fine. My feeling is if you end up rendering at the kind of resolution/detail level/scene complexity levels that would require 32GB, you'll probably want to use a render farm or at least a small cluster of machines anyway.

- Oshyan

[coremelt]

Thanks for that, the machine will be setup using Deadline render manager to accept both Nuke and Terragen renders in one queue, I'll have an older i7 quadcore system as well giving me a small render farm two machines 10 cores / 20 threads.  I'll put 16GB RAM in both machines, renders will be 1920x1080 HD.

One of the scenes we're going to create is a pull back from a pair of Plum Blossom trees on side of frame revealing a valley full of plum blossoms to the horizon, so potentially its a large number of XFrog plant instances.  16GB still be enough?

[Oshyan]

16GB should be enough. In a scene like you describe I would expect 3-4 populations of the plums for variety, and perhaps a few 10s of thousands of instances, with each being perhaps 50-100,000 polys. In addition I imagine there will be some ground cover, grasses or something, so another few populations there, but probably only needing to populate that nearer to the camera, perhaps half a million instances with 3-4 grass model populations, but grass models are going to be fairly simple. So I really wouldn't expect that push past 16GB. If you already know the size of your assets you can do some rough calculations to get a ballpark.

- Oshyan

[coremelt]

ok great, so Deadline breaks up every job into submissions for each frame, is it better with Terragen to submit one frame on all cores of a machine or to have say 6 frames rendering at once on a six core machine?  If so whats the memory usage per simultaneous frame going to be like?

[Tangled-Universe]

Here's what you can do with 16GB of RAM:

http://forums.planetside.co.uk/index.php?topic=13522.msg135623#msg135623

(this had 12 populations, at least 2 of them with millions of instances and all of the populations at least tens of thousands, all medium to high poly)

[TheBadger]

"Deadline render manager"

Thanks for mentioning this program. I did not know about it.
http://www.thinkboxsoftware.com/deadline/

[Oshyan]

ok great, so Deadline breaks up every job into submissions for each frame, is it better with Terragen to submit one frame on all cores of a machine or to have say 6 frames rendering at once on a six core machine?  If so whats the memory usage per simultaneous frame going to be like?

Best to run a single instance using 12 threads in that case. You will get a performance benefit from the Hyperthreading capabilities of the CPU as well. It's not at the same level as having additional physical cores of course, but you can get something like 10-20% additional performance. This is also advantageous for memory reasons as you're only running a single instance.

- Oshyan

[coremelt]

"Deadline render manager"

Thanks for mentioning this program. I did not know about it.
http://www.thinkboxsoftware.com/deadline/

It's a very handy system, and is free for a small render farm with two render boxes and unlimited clients.  I've had great results with it.
Here's the page on setting it up with terragen:
http://www.thinkboxsoftware.com/deadline-5-terragen/