FastSSS2 a real memory hog?

[simmsimaging]

I don't really use this mat much so I don't have much experience - wondering if it is normal for SSS2 to be massively memory intensive? I'm rendering a simple scene at 4-5K and the pre-pass phase is eating up all 12GB of my RAM, and then when that phase ends it just freezes up for a while then crashes Max totally. If I drop the SSS2 material the render works fine, and uses only 3.5GB of RAM.

I'm using BF and LC and rendering via DR and Backburner, but it also crashes when I run it straight out of my workstation with no DR and no BB.

If this is expected how do I optimize the memory usage of SSS so I can get this one out the door?

Thanks for any tips
b

EDIT: attached my material setting in case that helps. My first guess is pre-pass rate would go down, but I was getting really blotchy SSS when it was lower.

[vlado]

Storing all the illumination points could take a lot of RAM; for such a large resolution you can try to reduce the prepass rate in the SSS2 material.

For the crashing, if you are on a 64-bit machine, you can try to increase the Windows virtual memory limit.

Best regards,
Vlado

[simmsimaging]

Thanks Vlado.

I will try it again with a lower pre-pass - just wanted to be sure this was not something unexpected and thus some other user-error problem, and save myself a day of messing around for nothing

b