What are the stock voltages on that card??
Are you overclocking?/Do you have any experience with OCing?
Does the card work well at stock?
Alright dude, there are any number of things that could cause your throttling, and by any number of things, I mean 1) temps, 2) power issues, 3) the card itself.
1) Temps are easiest to fix. The best way to lower your tems are to:
a) underclock your card (I know not your favorite idea)
b) enhance airflow - done by cooling with water or, if using air, properly routing cables, moving away from stock cooling, and making sure your fans are optimally set up with intakes, exhausts and the like, remember, more fans arent always better
2) Power issues -- sometimes more challenging, and this is how I fixed my 68GT
a) check voltage on your power supply, make sure your video card is on it's own 12v rail, then make sure your PSU delivers a constant 12v. Time and time again throttling issues are resolved by getting a higher quality PSU.
b) once checking voltage has failed, I would try increasing the voltage to the core. This is a step up in risk, because it means BIOS modification and feeding the card more juice than it was designed to handle.
3) Unfortunately, not all cards will overclock. It's just a fact of life. There is a deffinite possibility that you have one of those cards.
As far as fixing my 68GT, I got a new PSU, and upped the core voltage, allowing me to get over my throttling issues. I significantly changed the temps, but my NV5 and AS5 usage resolved most of that.
