if you can get a temp sensor, then you place it between the gpu and the heat sink. Usually, our 9800 Pro dont have this built in. But, if you look at your P/N number on your card's board, you should see and number like this one: XXX-AOXXXX-00-AT. It will be something like that, but it will have the same groupings. The second set should the last four numbers of 7XXX or 8XXX. If it is like 7533 (mine) it was built like a normal 9800pro, but if it is an 8XXX then you have XT parts on your board. That means you have a temp sensor built in. So you can download Ati Tool (overclocking tool) and it will tell you your temps! That also means you can really OC the hell out of your card! AND_YOU_ARE, I assume you have OCed some, cause your 3dmark05 score is higher than mine before i OCed. Although it may be your processor.
**edit: I forgot to say this: because my board isnt an "XT" board i dont have a temp sensor, so I dont have a clue what the temp is. But, before i got the vga silencer, i could always touch the heatsink and it was never to hot to touch and after the i installed it, you can fell the air being exhausted out the back. That air almost never gets hotter.