Trouble with LightCache calculation

[sm@rt]

Hello!
I'm using 3dsMax 2008 and VRay render version 1.50.SP1. I used different version of VRay render before (such as: 1.48.03 - in 3dsMax7, and 1.5 RC3, 1.5 RC5). I'm using in GI for primary/secondary bounces Irradiance map / LightCache.
And I encountered a problem with LightCache calculation in VRay 1.50.SP1. Sometimes calculation progress "stoped", but 3dsMax uses almost all CPU time (I mean almost all CPU busy. I saw it in the Windows Task Manager ). There is no any calculation progress in that time but VRay increase the remaining render time. I can wait for progress in 40 - 60 minutes and VRay can increase the remaining time up to 28 hours without any progress...
But, when I change the camera position in scene - LightCache can be done in 15 - 20 minutes with the same settings...
I really don't know what cause this trouble
Some details:
You can see my PC configuration in my profile.
I was rendered image with 1024x768 resolution and the LightCache settings when I get this trouble was:
Subdivs - 450
Sample size - 0.02
Scale - screen
Number of passes - 2
Filter - Nearest
Interp. Samples - 10
After reading the VRay help about LightCache in http://www.spot3d.com/vray/help/150S...s_lightmap.htm I have changed LightCache settings to:
Number of passes - 1
Filter - None
Pre-Filter - 10
and I check "Use light cache for glossy rays" option.
But I have the same result - excessive render times...
Can anyone help me with this? Please leave your comments and advices anybody who know something about this trouble....
Thanks

[P2sta]

Hi, sometimes i have same problem, don't know hwats happend, but I think it is bacause not enought memory, but niot sure with it