98c is a bit too high. It's only rated at maximum to 105c. GeForce GTX 470
You're getting pretty close to possibly damaging it I would think.
I would raise your fan speed up while in gaming. And/or take it off Auto fan and find a nice manually set fan speed percentage. I myself use EVGA Precision
for that. You could also use something like MSI Afterburner
My GTX 480 with the stock fan running 2 monitors would only get about 80c maybe running the fan on auto while gaming. Where as I had the fan at manual 65% or so would probably reach up to about 70-75c in gaming - 2 monitors running though.
I have an aftermarket fan on mine now though, so I have lower temps overall.