If you're worried about memory usage, send a reminder to empty about trimming his max_particles field. Most of the particles have that left at the default of 1000 which allocates much more memory than is needed.
I don't use NVIDIA Control Panel to force any AA. I downloaded pickled_heretics particle pack and the FPS never drops below 40.
I've never noticed a difference so I don't bother trimming them, especially since it causes problems if I change the numbers later and I have to change the number and argh.
I have in ever in Empire Maps 20-35 FPS sometimes 10-15 FPS (in L4D 2 78-110 FPS) (in Insurgency 90-120 FPS) (in Battlefield 2 160-190 FPS) here my system: Microsoft Windows 7 Home Premium SB 64-BIT (all up to date design on performance (( Win95 style)) ) ATX Midi NZXT HU-001WH Special Edition - Pearl white Netzteil ATX be quiet! Straight Power E7 450W GIGABYTE GA-MA785GT-UD3H 785G AM3 ATX AMD Phenom II X4 955 3.20GHz (C3) AM3 6MB 125W Black... Cooler Master Hyper 212 Plus S775,1156,1366,939,AM2,AM3 1024MB Sapphire Radeon HD5770 Vapor-X GDDR5 Lite Retail PCIe (driver 10.4) 2x2048MB Exceleram CB8 DDR3-2000 CL8 Kit "Blue Culvert" 500GB Samsung HD502HJ F3 16MB 7200 U/min SATA LG GH22NS50 SATA
I got 12 fps in 2.24, now I get an average 4. Not 40, 4. But then again. My laptop is a sack of shit. So that's prolly why.
I put AA to 2x instead of 4x and I changed Texture Filtering to Off, although I don't think Texture Filtering hits FPS but the game doesn't look any different.