It's has 40 stream processors and is the best IGP on the market today. I upgraded my son's PC with an ASUS 780G and an Athlon X2 4200+
The only drawback with the motherboards is that the manufacturer's (not the chipset) limit the CPU's to 65 or 95 watt. Newer Phenom 125 watt B3's will fry the board.
Graphics wise it's like a complete last generation low end GPU. It works well in hybrid Crossfire with a 2400, 3450 or 3470 discrete GPU. Here are some previews and reviews:
Tom's covers the IGP in detail:
http://www.tomshardware.com/2008/03/04/amd_780g_chipset/
The graphics core can even be overclocked, and hybrid Crossfire brings 65% more performance.
Sharky Extreme looks at budget gaming performance:
http://www.sharkyextreme.com/hardware/motherboards/article.php/10703_3732211__1
Anandtech previews video playback:
http://www.anandtech.com/showdoc.aspx?i=3258&p=2
My son's 7 1/2 years old, and he's very mature as far as CRPG's go (he loves fantasy movies). He's been playing Fate (E 10+), Icewind Dale (T) and HOMM 3, 4 and 5 (T). The 780G's IGP can handle HOMM 5, which is the most graphically intensive game on his system. I installed Morrowind to test it and it runs Morrowind fine (he doesn't play Morrowind because it involves first person view fighting people, and not just goblins or monsters).
Later, I'll install Oblivion long enough to see if it can actually handle Oblivion (though we don't let him play M rated games). We don't have a 3470 yet, so it's not doing hybrid Crossfire. Overall, I'd say that the 780G board is a great budget PC solution for an Athlon X2 65 watt CPU system that's not used for the most recent games.
The boards will take a 95 watt Phenom, but that's probably a B2, so why bother? Perhaps they will have bios updates in December that will allow for a 65 watt 45nm Deneb. We can only hope.