Let me ask this.... have you changed voltages. You may want to get the Wallet ready because..... the 9400GT is quite old. I got one in my laptop and my its about 4-5 years old now.
Clock speeds don't change temps. Voltages changes temps, since Power=heat
No I haven't, they are locked on my card. Didn't know clock speeds didn't influence heat. If I can get to voltage, should I lower it? See if that helps?