i think your right, arma hates certain computers... my game runs about average 12 fps even though a have a prety decent computer. my settings are about as low as it can get without the game being blurry.
my comp specs are:
processor: intel(R) Core(TM)2 Quad CPU Q9300 @ 2.50GHz 2.50 GHz
RAM: 8.00 GB
system type: 64-bit operating system
hard drive: 988GB
Memory: 8192MB RAM
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7600) (7600.win7_gdr.101026-1503)
Processor: Intel(R) Core(TM)2 Quad CPU Q9300 @ 2.50GHz (4 CPUs), ~2.5GHz
to me thats just a bunch of mumbo jumbo and i hardly understand it but from what ive been told that should more than enough to play arma without a ton of lag but aparently not....