2.5.2: mouse clicks freeze computer for a fraction of second

[Mercury13]

In Nexuiz 2.5.2 mouse clicks freeze the computer for a short time.
More specific: shortly (ranging from immediately to 0.5s) after pressing a mouse button I get a noticeable lag (about 0.3s). Sound does stutter, too!

Computer: Core2duo 3 GHz, 2G RAM, GeForce 9600 GT, WinXP SP3, Logitech G5 mouse with Logitech SetPoint.

Close Logitech SetPoint: LAG
Another mouse (with ordinary Microsoft driver): LAG
Try SDL version: LAG
Try something that doesn't produce flashy effects (e.g. Nex zoom or just unbound button): LAG
Shoot with keyboard, with the same flashy effects: OK
Try Nexuiz 2.5: OK

Thanks in advance.

UPD. 2.5.1 DOES LAG, too.

UPD2. Strange way to circumvent. Create Hagar arena and fire hagar until it stops freezing. Then run the game you wish.