Hi tjphilly and welcome!
I own also own a DELL laptop, same SMBIOS, 8600M GS, CPU T8100 ... but can't replicate your issue.
(the GPU temp is still high, approx 60 C, but the CPU usually is around 40 C, effects are enabled in my case).
When you refer about 80 C temperature is this CPU temp or GPU temp (nVidia) ?
AS