DPC Latency
LOWER IT. There are guides on google.
Real Time latency Checker
DPC Checker
Provides detailed info into what is causing high latency.
LatencyMon
There was a post on Na.tf2 long ago...Remove any controllers/extra mouses
Do this...linky
Boost your timer resolution...Lowers DPC latency Dramatically.
DL here
With the free version, you have to start it up manually (you should try to install as service) and you have to leave it open. Works on windows 7x64.
Not to hijack the thread but I also have weird choppy game play while having great fps...