It seems as the general consensus ( or maybe a mr.sammorris posts that much ) that X48 is better than P45? First, lets look beyond the fact that X48 runs x16/x16 in xfire and P45 runs x8/x8 because overall, the P45 seems the most preferred until xfire comes into question. This is a bit baffling because even at x8, its still PCIe-2.0 at x8 which is means is at PCIe-1.0, and the bandwidth for that has yet to reach its limits. But what about other than that? Say someone was going not xfire, but wanted a single gpu and would overclock, game, and anything else relatively intensive, which would you ( anyone ) recommend then?
8x lanes can also reduce the stability of crossfire, not just its performance, and if you have two cards in there, they run at half speed, even if crossfire is disabled. This does have an effect on modern GPUs, so the X48 is the better choice for dual graphics. X48 boards also typically have better power regulation for dual graphics. If you will never use dual graphics, but do pretty much everything else, the Gigabyte EP45-DS3R will be perfect.
Can you define 'reduce stability' please? Like physically on the actual lane itself? Or, something to do with the software? "and if you have two cards in there, they run at half speed, even if crossfire is disabled" - That is kind of confusing, Im taking it you mean the lanes run at half speed? Or do you mean the cards? Ive read that P45 chipset is what has the better power regulations which causes it to run cooler, which in turn allows for a greater OC. Also, I not looking for a board as I have one picked out. ( I guess i put this in the wrong thread )
From what I hear, certainly with earlier revisions of catalyst 8.4, crossfire would randomly not be working, and you'd have to reboot the machine to get it to work again, things like that. The P45 boards have good power regulation and are overclocking champs. The X48s go further still, which allows dual graphics to work better, but all the extra stuff does mean it doesn't overclock quite as well as the P45s, they are still superb clockers though/
the P45s esp the Asus range, are doing supreemly well in th eOCing departement, well out doing the X48s. but thats not saying the X48s are slouches, and TBH on air the limit for Ocing is going to be withthe X48s as the OCability of the P45s vs X48s really come into play under LN2 and phase change. although the NB of the P45 is now a 45nm chip (IICR) so less voltages are needed to OC withthe P45s at an aircooled OC. from the benches i have seen, CF is not worth it unless at 1920 and over (even then the 4870 has everything licked at that res bar crysis), so for me, getting a new rig, the P45s would be of the up most ideal
Trouble is, if you're an extreme overclocker, and a gamer, chances are you have the money to use crossfire, and I'm still not sold on using crossfire with 8x lanes, not when cards use as much bandwidth as they do now.
You should try it to see your results with it, no current card can max out a pcie2.0 at 8x at the moment except for maybe an x2 gpu, from what ive read.
