I didn't notice at first that he mentioned bandwidth estimates (I just glossed over his post looking at SP numbers, sorry!) That is interesting if true, that would be one heck of a powerful IGP. a 4770 is certainly no slouch, in essence we'd get an 8800/9800GT power in an IGP... sounds too good to be true. IGPs have always been underpowered so as not to cannibalize the sales of discrete GPU cards, at least as far as I understood it.
This could be a big win for OEM designs. A mid-range quad core and a mid-range gpu, on a single chip is tempting, even more so if GPGPU takes off to any extent (say hello to the ultimate cheap photoshop machine). The laptop versions of this could easily take the mobile market.
But by 2011, 4670 to 4770ish performance will be much less impressive. AMD's 880g IGP could already be pushing (maybe even beating?) 4500ish performance, and it's set to launch within 6 months. In a year's time, 4770ish performance will be down to $50 cards, so it's not unreasonable to see IGPs at that level.
I could see AMD killing off the low end mainstream cards though. CPUs are their primary business, and adding a decent gpu to a cpu is quite the value-add. It's also a major point in favor of the AMD platform:
Get AMD cpu + gpu for $200, or pay $250 for an Intel platform to get the same performance.