In my mind, this is a nasty blow: RD600 is simply superior to any other LGA775 chipset and, in fact, to any AMD desktop platform chipset that I know. Where else could you have two PCI-E X16 slots for a full-speed CrossFire setup, augmented by an extra X4 slot for the (ATI again!) physics GPU card, a full complement of built-in interfaces, yet all that feeding off a 2+ GHz maximum overclockable FSB speed in sync with dual-channel DDR2-1000+ memory system run by an excellent memory controller, noticeably more efficient than the Intel one?
We're talking here about a substantial performance difference for the same CPU - with a better FSB & memory platform, combined with good cooling (water or better preferred!) on both CPU and North Bridge side, even a standard E6700 Conroe at 2.66 GHz default speed with 1,066 MHz FSB could achieve some tremendous speedups without the need to unlock the multiplier - the 1,600 MHz of higher FSB, and 4 GHz or higher clock speed? Yes, not every Conroe E6700 will do that speed (mine doesn't either, unfortunately, and the X6800 managed to do it briefly with Corsair Nautilus 500 water cooler, but not for long), but there are happy blokes around who seem to do it at speeds well beyond 4GHz anyway.
Even if not overclocking, but just keeping things as they are "officially", I'd expect anywhere from three per cent to 10 per cent 3-D & gaming & multimedia performance improvement when moving from i975X to RD600 chipset platform, all else being same - of course, the 10 per cent stated is a borderline gain for memory and graphics-intensive apps, especially in CrossFire setups.
While I expect the RD600 rollout to continue as planned without any changes - after all, it is around the corner anyway, and even support Intel's quad-core dual-die plug-in upgrades in the next few months, I seriously doubt there will be any further ATI chipset offerings for the Intel platform.
I guess Nvidia will be more than happy to step into the void, especially since its G80 GPU is around the corner too - a combination of an updated Nforce platform with Conroe-optimised FSB & memory controller, with the (temporary) GPU performance leadership of G80 in dual & quad SLI, does sound good to me - especially if bundled together with faster Core 2 Duo revs on the way now, like,say, X6900?
However, all is not lost, even if there is no counterbid by Intel for ATI. Simply, to make the parting friendly, or at least pleasant and polite, there is a straightforward solution: Intel buys the RD600 to bring it over as its own platform and, even better, hires over the RD600 design team to become it's high end gaming chipset platform. In return, the outstanding cross-license and other issues between the two parties get solved more amicably and, for the sake of shareholders expecting things to move, faster too.
Anyway, what would ATI do with its Intel platform design team after the merger? Might as well put together a package that gets the company some money, ensures the team keeps their jobs, and leaves the partnership with Intel on a high note - for both. Because, in this business, you never know who your next friend can be ... after all, who would have thought such a thing as ATIMD was possible just a year ago? I didn't, definitely.