Metro 2033 Max Settings Gameplay on Geforce GTX 275

Playing part of the second level of metro 2033 on max settings. Without fraps I usually get around 35 - 40 FPS Specs: CPU: Intel Core i5 750 @ 2.67Ghz Turbo Boost enabled VGA: MSI N275GTX TwinFrozer OC Edition Ram: x2 2gb Corsair 1600Mhz Motherboard: Asus P55D Pro Sli/Crossfire ready PSU: Antech True Power 750watt HD: x2 500gb HDs