It seems AMD/ATI have a strong playing card up their sleeve for Computex; Though i'm sure they were hoping to keep this under wraps until such time, The crew over at OCWorkbench have decided to counteract that somewhat and give us the early scoop on an exciting feature which will appear on some RD790 motherboards, this chipset being the successor to the RD580 (or 580X) variant.
We're talking four-way Crossfire action using either X1k or X2k series cards, thanks to four full-length PCI-Express X16 slots which can run 4x8 lanes (and are also re-configurable to 2x16). The performance gain from running four cards over two is apparently quite minimal (at least this early on in the picture), but the good news is that it can obviously be done and will just need time to mature with on-going driver support.
With the acquisition of ATi earlier this year, AMD is back to making chipsets for its processors. As we all know, the next generation of processors would require HT3 for more bandwidth. CrossFire support should also scale up.
The AMD RD790 chipset is an improvement over the RD580 or 580X chipset. The major difference is that it supports AM2+ and HT3.0.
In the test, a AMD X2 5000+ and a pair of DDR2-667 is used. The board you see comes with 4 full length PCIe x16 slots. It is fitted with 4 graphics cards. The interesting thing is that CrossFire works even with 4 cards, but performance is not ready for 4 cards to improve the performance. The PCIe slots can be configured to run in 2 by 16 or 4 by 8 in CrossFire mode. The south bridge is still the SB600.