It is easy to explain why the mainboard lacks PCI Express x1 slots: two PCI Express lanes are used to connect the chipset’s Bridges, thus leaving only two lanes free. The South Bridge lacking an integrated network controller, one of the lanes is for the external 88E8052 Gigabit Ethernet controller from Marvell. The last lane is connected to a RAID controller SiI3132 which is responsible for the mainboard’s two Serial ATA-II ports. This controller is most appropriate here because as we found out during the installation of the operating system the four-channel Serial ATA controller integrated into the South Bridge is in fact two dual-channel SiI3112 controllers.
The developers of the SB450 must have thought it unnecessary to develop a Serial ATA controller from scratch but instead used a ready-made solution, integrating the appropriate logics into the chip. The development of the South Bridge was thus made cheaper and simpler, but stripped it of Serial ATA-II support (which may lead to compatibility problems with modern hard disk drives) and RAID 0+1 mode and also created a potential bottleneck since the SiI3112 uses a PCI interface rather than the faster PCI Express bus.
We didn’t perform any tests of the disk subsystem connected to the South Bridge of the RADEON XPRESS 200 CrossFire Edition since it would have been beyond the scope of this review, but we are sure it would be slower than a hard drive connected to the external controller.
A popular HDA codec ALC800 is employed in the audio section of this mainboard. The FireWire interface is also supported thanks to a VIA VT6306 chip. Thus, the reviewed mainboard is a high-class solution with support of all modern standards and interfaces, but leaving no room for further modernization.
The power connectors are placed properly. To improve stability in multi-GPU modes the mainboard has an additional Molex connector that reinforces the power circuit of the PCI Express x16 slots. ASUSTeK Computer uses an analogous solution in their mainboards – they call it EZ Plug.
As for the placement of the IDE and FDD slots, it is not perfect. The IDE slots are right behind the PCI Express slots and may become blocked by long graphics cards. For example, the IDE connector closest to the PCI Express x16 slots got blocked when we installed an NVIDIA GeForce 7800 GTX. The same problem may arise if ATI’s new-generation graphics cards turn to be as long as NVIDIA’s modern devices.
The FDD slot is located behind the 24-pin power connector. This is not very handy, but after all modern systems seldom use a 3.5” floppy drive. It should be acknowledged that wiring a multi-GPU-compliant mainboard is a daunting task as the engineers must put two PCI Express slots as well as many other components in a limited area. It is probably impossible to place each component conveniently for the user, especially with the classic “North Bridge + South Bridge” design, but approaching the ideal as closely as possible should be the goal.