Mouse Lag when attacking players

When I'm engaging an enemy (generally as aliens), my mouse lags out and the response time increases. It is only minor, but is still enough to miss easy kills. This issue occurs on all maps and it only started happening about 2 builds ago.

I've tried nuking NS2 all together, however it made no difference.
I've installed the latest mouse drivers, no fix.
I've installed the latest graphics drivers, no fix.

Any other suggestions?

Thanks