In the release notes buffybill linked (2nd link), the document lists the following:
Fixed Single-GPU Issues
GeForce 7 Series GPUs: Lock On: Modern Air Combat–graphics corruption occurs. (page 9)
NVIDIA Issues—SLI Mode
GeForce 7 Series GPUs: [SLI], GeForce 7950 GX2 Quad NVIDIA SLI: Lock On– slow performance in the game.
GeForce 6 Series GPUs: [SLI], GeForce 6600, SLI, Windows XP: Lock On: Modern Air Combat has lower than expected performance at high resolutions with antialiasing enabled.