I've been running AH fine on this Win7 Home Premium 64bit, Intel Core i7-2600, 3.4GHz, 8Gb RAM, NVIDIA GeForce GT530 Machine. Never had a crash, just the occasional disco every couple of days.
Since 2.27 the game "stops responding" about every 10 minutes, usually during a graphics transition, but also during a dogfight for instance when the scene is changing rapidly but no view alterations are being asked for.
Turned off all bump maps, toned down the graphics below what they were. Checked that NVIDIA drivers and DirectX were up to date, they were, but installed a beta NVIDIA driver just the same...no help, game is unplayable.