Great test and thanks so much for the instructions on how to configure Speedfan. I could never figure out how to make Speedfan control fan speed on my 780G board till now.

It's good to see that Gigabyte went the extra mile on heatsinks for the northbridge and buck converter mosfets. NB temps aren't reported on the GA-MA78GPM-DS2H board, and that board has a marginal heatsink that needs some air flow to work.

Can this board power down a discrete ATI videocard when in 2D mode or is that still not supported?

Unfortunately no. Nobody has yet to produce a chipset/motherboard that can do this yet that I've seen. Both ATI/AMD and nVidia have been talking about things like this but apparently neither have figured out how to do it. And laptops are probably where we'd see this first as it would help more with battery life and such.

Some laptops already supported it AFAIK.

Correct - See the Lenovo T500.

I got one for just that reason.
however -- its NOT automatic. I have to click on a menu and tell it to switch between the discrete and integrated card. Its currently Vista Only, and it took several driver updates to finally get the process working right.

but when it works its great

I'm trying to get an idea of how hot the northbridge on the non-IGP 790X/SB750 GA-MA790X-UD4 and MA790XT-UD4P boards might run (see my fretting and Mats attempts to reassure me: http://www.silentpcreview.com/forums/vi ... 628#460628)

Is there any chance someone could test the GA-MA790GP-DS4H with the IGP disabled or at least just stressing the CPU alone to see what difference that makes to the northbridge temps?

this would be a very good starting point for a comparison with DFI LANParty JR 790GX-M2RS !

danielG's kindly posted some temps for the 790X-UD4here and they look pretty OK to me.

I'm trying to get Gigabyte to tell me what the thermal sensors are monitoring. I made the mistake of mentioning Speedfan and they told me to contact the author

Well here's the rather useless reply I got from Gigabyte to my question "How many themal sensors are on the board and what are they measuring?".

"There is only one system thermal sensor to detect system temperature.

As for location of the system thermal sensor, sorry but this kind of information is not provided to end users."

This not only appears to be incorrect (I think danielG's tests show that there's more than one sensor on the board) but doesn't show much regard for their potential customers.