The single HD 4870 does an excellent job at standing its ground, floating around the GTX 260 XXX card we have here today. Like the HD 4850, turning on AA doesn't cause the card to fall to its knees as was the case with the HD 3800 series of cards of last generation.
The dual-slot cooler does a good job of keeping noise to a dull roar, while helping drop those temps as well. This was something that was a concern with the HD 4850; there isn't a doubt in our mind that we will see companies begin to change the HD 4850 cooler to dual-slot options to get the temps way down and likely below it's big brother; the HD 4870.
The main problem that we really have is at 3GHz on a quad core we do feel somewhat CPU limited, with little gains seen with the implementation of CrossFire in the real world environment. Fortunately, we will be strapping the two cards into a 4GHz test bed soon enough, which should hopefully let these cards shine.
If you're looking for a new single card graphics card solution, which way do you go? - Well, the HD 4870 manages to come in lower than the GTX 260 while on the most part being able to compete with it, though the latter card is heavily overclocked. That's good news for ATI since the HD 4870 here hasn't got its clockspeeds increased at all.
If you have an SLI motherboard, well, you have two options. If you're going to actually make use of SLI, go for the GTX 260; you really don't have any other choice when it comes down to it, since the board can't make use of CrossFire. If you're not going to make use of SLI, we would probably opt for the HD 4870 and begin to overclock it! If you're on an X48 or X38 board, the choice is easy; go the HD 4870 and start saving for that second card straight away.
If you're on a board that doesn't have dual x16 slots, then we would probably look at the HD 4870, or if money isn't an issue then the GTX 280 would make sense due to the simple fact that the GTX 280 is the fastest single GPU solution on the market today. The good news for AMD is that it doesn't smash the HD 4870; the leads are only small and the price gap is literally double.
As someone who is about to build a new personal test system, I will be going for a pair of HD 4870s on an ASUS P5E64 WS Evolution which carries with it dual x16 slots. The price of the X48 based chipsets compared to 780i and 790i are significantly lower, and for the most part enthusiasts will say that the Intel based chipsets are the nicer boards.
With that done, it's time to jump in the car and head on over to see the boys at IBP, because like the HD 4850 I think once we give these cards another GHz to play with we should really see some significant performance increases.