[update]
It happens with more games, like Valve's Portal, and the solution is to quit E-LEET. See
post #8
[/update]
When I move the mouse while pressing forward or strafe keys, the game loses mouse updates very frequently (from every few seconds to several times a second) so the perceived movement is not a smooth turning, but a random turning-straight-sudden_big_turn-turnig-straight-sudden_big_turn movement very disorientating.
The only way to keep orientation on the initial tunnels of Penumbra: Overture it to release the keyboard, turn using only the mouse, then stopping the mouse to go forward...
This happens with the version sold on The Humble Indie Bundle, over Windows 7 64-bit, core i7-860 @4.0GHz, 4GB ram, GTX 275 using a G15 keyboard and G7 mouse, and with all drivers updated.
No graphics options change solves the bug. Changing USB report rate to 125Hz, 200Hz or 500Hz and checking other USB ports does nothing also (mouse and keyboard are connected to differents ports, without any hub).
How can we overcome this bug? It is extremely irritating...