I have a question about cpu usage and bitmap sizes in scenes.
I’ve just done a test render of an interior, no materials applied, just to
check out what the lighting was like. I’m using light cache and IR map
and during the calc stages the cpu was being used 100%.
Then I applied a brick material to the walls, the bitmap size is 5000x7700
with 24bit colour depth and i re-rendered the scene. Now, during the calc
stage my cpu usage has dropped and hovers between 68-75% and the
light cache takes yonks to generate.
I have the bitmap pager turned on and the default geometry set to
static, i’ve tried playing with dynamic and that does’nt help, there is also
no displacement in the scene.
If it’s of any use my system is an X2 4800, 4gig ram, windows XP64.
I’m not too sure what’s going on and why it should do this, I’ve read
through other threads about similar problems but nothing seems to help
and the light cache is taking an absolute age.
Can someone shine some light on this please 
or should i just stick to
using lower res bitmaps :?:
many many thanks
steve
there is a plugin for seriously high res textures called wavgen
hi da-elf, do you know if this cures the cpu only running at 70% with hi-res
bitmaps :?:
UPDATE
I halved the size of the bitmap i was using to 2500x3850 and it’s rendering
fine again. I think i’ll run a photoshop process on all the new arroway
textures i got, make a copy of em and half all their sizes 
steve
I find that when the CPU’s are not at 100% it is because of memory issues. Have you tried disabling the bitmap pager and turning up the dynamic memory limit significantly? I turn mine up to between 3000-4000 mb and I can have multiple high-res bitmaps and multiple high-res HDRI environment maps that will load without any difficulty and still render at 100% CPU. I have a similar spec as your machine except I have dual dual-core opterons.
I’ll give it a go, I thought i’d solved it when i halved the size of the bitmap
i was using, but as i added more bitmaps to the scene the problem came
back.
cheers
steve
Hi Clifton, cheers for the suggestion, I gave it a try but it did’nt work 
Is this a bug or is it a problem with most rendering software :?:
It seems bonkers that I invested money in good hi resolution bitmaps
only for the rendering software or max or what ever is causing the
problem to take a fairly big performance hit, because not using 100% of
your processor really does add to rendering time.
Is wavegen the only way of getting the computer to render using 100%
cpu when using hi-res bitmaps :?:
steve
Sorry it didn’t work. Maybe if you post a sample scene I could test it out on my machine.