Bizzar Lag USB related

resently occasionaly i have been getting a very strange type of lagg...
used to be completely fine the only thing that has changed since then is a new keyboard.. yeah i know right.. how can it be that?
but when the lagg happens i will open up a game fine, but my cursor will be really juddery.. say i was playing e.g. counterstrike source. i can join a server fine.. join a team blah..
if i stand still or use WASD to move its fine!! 100-150 fps!!
but as soon as i move the mouse ITS A SLIDESHOW!!!
i first thought i could only get rid of it by restarting my comp. but i tried unplugging keyboard and putting it back in, and the lag went away.... (for the time being) sooooo something to do with keyboard? mobo?
my specs
Mobo- p5n-d
gfx card - 8600gt
processor- e8400
KEYBOARD- Roccat Arvo
Mouse- Logitech g500
(hmmmm wait a sec both my mouse and keyboard use 1000hz polling rate i have heard this can sometimes play havok with stuff duno tho :S)
3gigs ram
Windows 7 32bit
Asus Xonar dx

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