Gaming (Bootcamp) iGPU temperature

Hey guys,

I just installed Win8 on bootcamp for the first time to try some games what I cannot play under Mavericks. So I downloaded AIDA64 app for monitoring temperatures to test how it goes with playing.

There is one item I don't recognize from iStat app on Mavericks. That item is called as "iGPU" and it measure kind of higher temp compared with just "GPU Diode".

In idle mode "iGPU" have about 47°C, but when I playing (for example World of Tanks on High settings), the temperature raise into about 90°C and in that moments starts fan going about 1600rpm and temperature is holding little under 90°C.

So my questions are:

1) What exactly does mean "iGPU"? Because nothing like this isn't in my iStat app on Mavericks.

2) Is this temperature okay for this part of graphic card or whatever it is?

Thanks for you answers!