blender RAM maximum limit

I’m working on a project that requires for me to swap between applications frequently … one of these is blender …
the issue is … whenever I render my scene blender eats up more than 3gigs of ram and thous pushes everything else to swap … which causes all the other programs to become sluggish …

Is there some way to put a maximum ram limit on blender?
im not super concerned about render speed here … just ram usage.
I’m running on a 4gig (64 bit) linux system.

Since you are already on a 64 bit system my advice is to get more ram. You’d see great improvement and stability overall.

but … its already stable … blender is the only program i use that goes over my 4 gigs
I also am worried that going above 4 gigs will mess up my 32 bit winxp boot

Booting any 32-bit OS on a computer with more than 4gbs of RAM won’t be a problem. After all, even with 4 gbs, 32-bit Windows (all versions) will actually only see 3.2 (or perhaps it’s 3.3) gbs. That’s already 700 or 800 mbs the OS simply refuses to see/use. So, adding any amount more will yield the same results. The OS will address the first 3.2 gbs and that’s all.

Do a little background research into how a CPU addresses RAM and you’ll get a much clearer picture of what’s going on and why adding extra RAM won’t be a problem.

In a nutshell, it comes down to how many bits are used to access a particular address in RAM. A 32-bit OS uses 32-bit addressing, so any RAM that requires 33 or more bits to be addressed is effectively invisible.

Hi, I never saw a scene with 3-4 GB ram usage except simulations, fluids or during render.
Sometimes user set high subsurf or multires values and get millions of polys or copied objects multiple times without need it.
You could try to switch of Global Undo in User Preferences > Editing.

Cheers, mib.

4gb is fairly low for anything beyond simple tests. If you’re serious about this blender thing, get at the very least 8, but 16 or 32 would be much better. At work we’ve got 32 GB and we have in fact run out of it a few times, due to high res textures, particles and geometry.