In this respect the functionality of the new North Bridge in terms of system memory support looks quite significant. ATI managed to design dual-channel DDR2 SDRAM controller that has no analogues as of today. It supports truly asynchronous memory clocking that is not connected to FSB frequency in any way. According to the formal specification, ATI RD600 supports DDR2-667 and DDR2-800 SDRAM, however, in reality its functionality goes far beyond that. The chipset allows setting the memory bus frequency to almost any frequency you can think of today, and it will not be in any way tied up to the FSB speed. This feature is very important for overclockers as it allows overclocking the memory independently of the CPU and to avoid looking for specific memory modules if the system features an overclocked processor.
Another important advantage of the ATI RD600 DDR2 SDRAM controller is the support of 1T Command Rate. Although this is not surprising at all these days: nForce 680i SLI also boasts the same feature. However, unlike the Nvidia chipset, ATI RD600 also supports 2T Command Rate and 3T Command Rate, which may sometimes improve the operational stability and increase the overclocking potential of the memory modules.
As for the CPU support, the new ATI core logic set is compatible with any LGA775 processors available in the today’s market. Of course, since very soon we will see Intel Core 2 Duo CPUs designed for 1333MHz Quad Pumped Bus speed, it is very interesting to see how well RD600 will work with them, too. Although there is no official data about it yet, we tend to believe that the chipset is well equipped to deal with the new processors just fine.
Although ATI was initially going to use RD600 with the new SB650 South Bridge, the chipset we are talking about today uses an older South Bridge model – SB600. We have already discussed its functionality in detail in our previous articles: it supports ten USB 2.0 ports, four Serial ATA-300 ports, one Parallel ATA-133 channel, six PCI busses and High Definition Audio (Azalia). The serial ATA controller built into the chipset South Bridge supports RAID 0, 1, 0+1, NCQ and up to 3Gbit/s data transfer rate, but doesn’t support RAID 5.
As ATI’s chipset has limited functionality in terms of expansion busses support and uses older South Bridge model, RD600 doesn’t look that dramatically impressive against the competitors’ background:
Nevertheless, ATI chipset boasts all necessary basic features that can be enhanced with additional onboard controllers if needed. And since RD600 core logic set costs less than the competitors’ solutions, the mainboards based on it should be priced quite affordably even with onboard controllers added to the PCB.
You shouldn’t also be concerned with the low bus bandwidth between the chipset North and South Bridges. The thing is that all high-speed interfaces in the ATI chipsets are placed inside the chipset North Bridge, therefore, the South Bridge doesn’t really need high-speed connection. So, it looks like all the above mentioned drawbacks of ATI RD600 are definitely not fatal.