ATI RD600: AMD Chipset for Intel Processors
Before we go into details about the new DFI mainboard, we should say a few words about the ATI RD600 chipset. The main intrigue about this chipset is that it is the first discrete chipset from ATI supporting Crossfire technology and Intel processors, which has been recommended for high-performance systems. The previous integrated ATI chipsets for Intel platform could boast neither high performance, nor sufficient options for successful overclocking. Therefore, RD600 is definitely a dramatically new solution and hence of extreme interest to us.
Let’s take a closer look at its design:
As you can see from the chart above, ATI RD600 is a dual-chip core logic set. The North Bridge is the RD600 chip, and the South Bridge is the SB600 chip, which we have already mentioned in our review called Chipsets for Socket AM2 Platform: ATI CrossFire Xpress 3200 and Nvidia nForce 590 SLI (now it is called AMD 580X Crossfire) for AMD processors. The chips of the core logic set are connected with one another via the A-Link Xpress II bus, similar to PCI Express x4.
Although the RD600 chipset is officially called Crossfire Xpress 3200, just like the earlier solution for AMD Athlon 64 processors, you shouldn’t be misled by the name. Even though these both chipsets use the same South Bridge doesn’t make them close from the feature standpoint. Even when it comes to implementation of Crossfire technology. The thing is that ATI RD600 North Bridge supports strictly limited number of PCI Express lanes. While its namesake for AMD processors supports 36 PCI Express lanes that allow implementing two fully-fledged PCI Express x16 interfaces in the mainboards based on it, RD600 has only 20 PCI Express lanes. As a result, the new chipset can only support two graphics cards as PCI Express x8 + PCI Express x8. However, we know this narrowing of the graphics bus bandwidth results in insignificant performance reduction. Moreover, there are no chipsets for Intel processors in the market today that could work with Crossfire technology designed as PCI Express x16 + PCI Express x16.
Besides two graphics busses, ATI RD600 chipset also offers an additional PCI Express x2 bus for the third card – physics accelerator, and two PCI Express x1 busses that the mainboard developers can use at their own desire: for example, for network or Serial ATA RAID controllers.
It is quite hard to tell why there are so few PCI Express lanes in RD600. As the previous chipsets from this developer look much more advanced from this prospective, we get the impression that the engineers just were trying to save some money and effort here.