Thanks Pixho!
You came to my rescue once again.
I just read another post in this forum stating that 8k might be the highest possible res.
So I downsized it to 8k by 4k (8192*4096) and that works fine.
I also tried the makebot command.
ie: makebot -i "/path/verylargeTexture.iff" -o "/path/out_bot_file";
This reduced rendertime by approx 50% in my test scene, and a lot of memory saved too. Very cool 
Now, Can anyone explain to me the difference in turning the cache on and making a bot file?
Also making a low res version for opengl view, then replacing at rendertime seems reasonable.
Dont even know where to get ram for my sgi 320 and if its even worth it...
-Audun
Before bot
Resource Usage At End Of Rendering
95 Page faults
279.003 Mb Peak total size(Estimated)
130.001 Mb Peak arena size
====================================
144.212 Mb Current
0.131 Mb NURBS Surface Shapes
3.932 Mb MEL
1.049 Mb NURBS AG
6.991 Mb Render Cache
0.328 Mb Data Blocks
117.441 Mb File Texture Mipmaps
0.131 Mb Transforms
====================================
Total Time For Render (hh:mm:ss): 00:00:41
Total Elapsed Time For Maya (hh:mm:ss): 00:00:45
After bot
Resource Usage At End Of Rendering
198 Page faults
49.377 Mb Max resident size
31.166 Mb Peak total size(Estimated)
12.560 Mb Peak arena size
====================================
26.579 Mb Current
0.131 Mb NURBS Surface Shapes
3.932 Mb MEL
1.049 Mb NURBS AG
6.991 Mb Render Cache
0.328 Mb Data Blocks
0.131 Mb Transforms
====================================
Total Time For Render (hh:mm:ss): 00:00:19
Total Elapsed Time For Maya (hh:mm:ss): 00:00:23
