I set bEnableEnviroEffectsOnPC=1 in my FALLOUT.INI yesterday, to gain the reverb and positional audio effects I've read about. Afterwards, frame rates seem fine, except for this one time: In the http://fallout.wikia.com/wiki/Robot_repair_center, fighting the Mechanist's various guards, I'm getting single digit frame rates whenever a couple robots or turrets start blasting away at me.

This NEVER happened with the original or default setting. And it stops if I set bEnableEnviroEffectsOnPC=0.

Has anyone experienced it and know a fix?

Thanks!

Antec Twelve Hundred case
Antec TPQ-1000
Intel Core i7-950
COOLER MASTER V6 GT
EVGA 131-GT-E767-TR LGA 1366 SLI3
EVGA SuperClocked 015-P3-1582-TR GTX 580 1536MB
CORSAIR Vengeance 12GB CAS 9
SAMSUNG EcoGreen F2 1TB
Seagate Barracuda Green 2TB
Samsung SH-222AB (x2)
Sabrent 2P USB 3.0 PCIe
Samsung S23A300BS/2A (S23A300B) monitor
Windows 7 Home OEM 64 bit SP1