Weird video card temps

Hi, i have a problem with my video card (Leadtek PX8800GT). After i reinstalled windows (Windows Vista Ultimate x64) i noticed that the temps were weird. Normaly the GPU would be at 56 degrees in idle but now it stays at 70 (Artifact scaning with Ati tools would normaly take it to 72 degrees after a few minutes but now after only 15 sec it's at 75). First i thaught that maybe the program was reporting wrong but both GPU-Z and Everest say that it's at 70 and i checked with my hand... i can't keep it too much on the card it's too hot. I tuned up the cooler at 60% and now it stays at 57 but it stayed like this with 30% power. The only thing that i found strange were the voltages: on the 5v line it gives 5.46v and on the 12v line it fluctuates a lot from 12.15v to 12.52v. Now i don't know if this is a problem or if it's just a bad report. oh and the GPU Vcc is at 3.27v. 1 more thing i noticed is that without a graphics driver right after i installed windows the gpu is at 60 degrees but goes up to 70 after i install the driver (tried with older drivers but same problem) And maybe i'm just imagining but the PC sounds louder than before.
So what could've happened ? is the PSU broke or the video card cooling ? Or what else can it be ?
my rig:
MB: Asus P5KR | CPU: Intel Core 2 Quad Q6600 > Zalman CNPS9700LED | RAM: Corsair Twin2x 2x2048 DDR2 1066, XMS2 | GPU: Leadtek PX8800GT TDH 512MB | HDD: Samsung SpinPoint 400GB Sata2 | SB: Creative Audigy 2 | PSU: Thermaltake 550W | CASE: Recom Miditower Backdraft Black | Display: Samsung 2232BW | Windows Vista Ultimate x64 SP1