Something like that.. they use a method which streams textures from the harddrive, so apparently using a SSD (solid state drive) or defragmenting the Arma2 folder frequently with a good tool has helped people gain lots of FPS, fix glitches, stopped crashes, etc . Usually hard drive speed doesn't effect anything except copying/moving large files more quickly, but apparently having a fast write/read speed on the hard drive improves the fps and stuttering a lot on Arma2. Once I used MyDefrag I've been very happy with the fact my comp boots up literally 5x faster anyways, and I don't have much problems since I keep less than 60GB or less of stuff. However, the Arma2 folder had lots of fragmentation and I know it did increase my FPS alot in Arma2 when I did it. The Arma2 folder fragments a lot more than usual.. mostly because of this constant opening/streaming of data which only Arma2 seems to do.