Hi,i just bought a MSI 9800GT 512mb factory overclocked VGA. core clock: 660 memory clock: 950. This card is having a copper piped heatsink, looks pretty nice than other VGA's brands. even with COPPER cooling the idle temperature is 48 celsius?. in load it's about 51 celsius?
I have the same MSI 9800 GT as you. I run them SLI and after 10 minutes of Crysis on high settings, they'll go to 75 C. However if I set the GPU fans manually to 100% and leave out the case side panel, the temps max out to around 68, 69 C.
Under load, your card stays cool compared to most 9800 GTs. 48 C at idle is very normal.