I have read every scrap of information I can find on crossfire performance on various chipsets. Don't bother linking it because I've read it, unless it's in some other language.
-The P45 chipset is now about as mature as it's going to get.
-There are new x48 boards out.
While we may still need some improvement on ATI drivers, they have had long enough.
We need testing. We need single and crossfire setups. We need 4870 crossfire testing across at least 5 boards, x48 DDR2, x48 DDR3, P45 DDR3, P45 DDR2, x38.
We need comparison charts that include the most common resolutions such as 1680x1050.
We need them done in Vista 64 bit.
The more I look at the Tweaktown comparison the more I am disappointed with it. It was done early, and things have changed. It draws conclusions based entirely on resolutions beyond the reach of most of us. I have seen some very recent testing that indicates there may be general performance issues with P45 not related to crossfire at all, in other words it 's not actually the x8 crossfire that is the problem.
Is there anyone out there with the resources to do this right?
There was one comparison that showed very little difference between the chipsets.... but the testers used 3850s in crossfire because that was all they had. This might lead you to the conclusion that P45 should only be used with crossfired 4850s or lower... but we need Proof!
I can't think of an article I want to see more, and I can't think of one that would generate more web traffic for some tech site.
Anandtechs P45/P43 mobo shootout is now over a month overdue. Toms review is still MIA. I'm pretty surprised by how poorly this issue has been reviewed. There was a swedish site that posted reviews of the crossfire potential of the P45, it pretty much followed Legion Hardwares information. http://www.legionhardware.com/document.php?id=761
Thanks for the link, dirtmountain. Very interesting article.
Weird, HD 4850 CF in Crysis, 54 fps on X48 (PCI-E 2.0 16x+16x) and 43 fps on P35 (PCI-E 1 16x + 4x). I expected the P35 limitations to hurt a lot more.
I loved this paragraph most (the bold font is mine, not in the original):
Right now it is possible to purchase a decent ASUS P45 motherboard, such as the P5Q Pro for example, at just $150 US. Pairing this board with Crossfire Radeon HD 4850 graphics cards would cost around $550 US, making for an extremely lethal combo! The cheapest ASUS X48 board on the other hand, is the P5E Deluxe at $220 US, and we are not sure that at this price it is worth the 5% Crossfire performance gain. Still, if you are looking to get the most out of your Crossfire setup, then the X48 is the weapon of choice.
With Antec 900 and Silencer 610W at $80 each and some really good CPUs under $200, that means a fantastic gaming PC under $1000. Wow...
There's indications in the article that DDR3 could actually be worthwhile in that board though, especially for memory intensive apps.
There seems to be some validity to the idea that 4870s in crossfire will get throttled down on a P45 board... but then I start thinking about PCI-E 2.0 and the power increase from the slot, and I have to wonder if the next generation of cards might not make better use of that.