At least now we know that performance for HD68xx series will be 5-6% slower in Xbitlabs, Computerbase, PCgameshardware compared to every other review, and probably the same is going to be true for HD69xx series going forward. So at the very least, this new information regarding their testing methodologies is important to us the readers. Personally, I will continue to review Guru3D, AT and Xbit/ComputerBase/PCGamesHardware, but now it will be easier to explain why the numbers don't match.
The problem of canned/synthetic benches like the 3dmark is not that NVIDIA/AMD can optimize. Optimizing performance by get rid of unnecessary/wasteful work isn't a bad thing. The problem with canned/synthetic benches is that they not represent actual games or even entire games. I generally skip all the synthetic benchmarks on any review.
Someone that is scientist might be annoyed with companies creating short cuts but what matters for the consumer is the image he sees while playing, regardless if the GPU is doing all the work the game is asking for or just enough work to present an identical/equal image had it done the full work.
Of course optimizations have downsides - sometimes it creates an error/bug.
So if there is an optimization that induces less IQ but I can't see the difference unless I'm still and have zoomed I don't know how many factors, I'll disregard it. Of course there will always be someone that just have an incredible eye sight and spots the most minute difference, but those are the exception.
Is there shimmering texture on that HL2 video - yes, there are. And aren't corrected by turning HQ on or even disabling CAT AI. For me that seems a bug but I might be wrong. In teackmania and HL2 you can even see the mipmap transition in a screen shot (happens for 5800 series in trackmania too as the AT 6800 review shows).
The oblivion screenshots and he witcher screenshot on the other hand don't show if anything at all.
If the IQ is really lower then it should be visible in all the games and so there will be no problem in picking a game like SC2 or AvP or BFBC2 or whatever and show this, is there?
EDIT:
I think you and I can agree or disagree with the approach used (and that's cool esp. since you always approach differences of opinion with respect ). However, we have more up-to-date information on how their reviews will change - and that's important.
I guess I fit in the category of "I don't really care about this minute difference" and I'm just debating cause I like to do so.
I would be worried if someone just went ahead and showed huge differences that couldn't be denied by even the biggest fanboy of either company (hmm maybe they would still deny) and then I would lose all the trust in the reviewer sites and I would have to start asking/demanding demonstrations in the PC shops. But these are at best minute differences, with the shimmering being the exception.
Maybe I should - "I want to see this game with a 6870 an with a GTX460".