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MSI's 9130 K8T Master2: A KT8T00-based dual Opteron
MSI's 9130 K8T Master2 is a very interesting low-end workstation and server motherboard. It's based on VIA's do-everything K8T800 chipset, which can scale from 4- and 8-way servers to single-CPU desktop systems based on the Athlon 64. The first thing you'll notice about the 9130 K8T Master2 mobo is those two matching 940-pin sockets for Opteron chips.

Dual sockets for dual-processor action

Yep, this puppy's a dually. VIA's K8T800 gives the MSI 9130 several advantages over the SK8N, and multiprocessor operation is one of them. VIA's K8T800 chipset also has a more traditional layout than the nForce3 Pro, with separate north bridge and south bridge chips. VIA's proprietary, HyperTransport-like V-Link interconnect links the two at a rate of 1.06GB/s. By breaking things out into two chips, VIA can update the south bridge silicon independently from the north bridge, or vice-versa. VIA's 8237 south bridge includes a true Serial ATA drive controller with support for RAID 0 and 1, plus a pair of ATA/133 interfaces. The 8237 also has a six-channel AC'97 audio controller, which MSI pairs up with an ALC210A codec. (The audio ports themselves are located on a PCI slot plate that connects to the 9130 via a header.)

Much like the SK8N, the use of a Realtek codec prevents the 9130 from earning VIA's Vinyl Audio designation. MSI bypasses VIA's Fast Ethernet controller, as well, and incorporates a Broadcom GigE chip.

A block diagram of the K8T800. Source: VIA.

The MSI 9130 has only 32-bit/33MHz PCI slots, but the K8T800 is capable of supporting faster PCI standards, all the way to up PCI-X, by an unorthodox arrangement in which a VIA PCI controller chip hangs off of the north bridge's AGP 8X port. This setup could be useful for servers, where PCI-based graphics would suffice, but not for workstations, where the AGP port would best be dedicated to a graphics card. Accordingly, MSI has given the 9130 an 8X AGP Pro slot.

The MSI 9130's talents are considerable, but MSI chose a peculiar cost-saving measure in designing this board. Although the 9130 has dual Opteron processors, each with its own dual-channel DDR memory controller, MSI connected only one of the two CPUs to DIMM slots. The second CPU has no local memory, just as indicated in the diagram above. This is not a typical arrangement for multiprocessor Opteron systems, and VIA says the K8T800 works fine with multiple processors using multiple memory controllers. The MSI 9130's performance isn't bad, as you'll see soon, but it has half the memory bandwidth of optimal dual-Opteron configurations, and the system's second processor must always resort to non-local memory access. What's more, the 9130's multiprocessor config offers less redundancy. If CPU 0 fails, CPU 1 cannot access memory, and the system croaks. And last but not least, you'll need to use 2GB DIMMs if you want to reach the 9130's max of 8GB RAM, because it has only 4 DIMM slots.

The 9130 does have another leg up over its nForce3 Pro competition, though, thanks to VIA's Hyper8 technology. Hyper8 is a complete implementation of the fastest link afforded by the HyperTransport spec. On the K8T800, the HyperTransport connection between the north bridge and the primary processor is 16 bits wide in each direction and runs at 800MHz, yielding 6.4GB/s of bandwidth. NVIDIA's solution, by contrast, has only 3.6GB/s of peak bandwidth between the CPU and the nForce3 Pro chip. To highlight this difference, VIA has released a HyperTransport analysis tool, and as you can see in the screenshots, it indicates the nForce3 Pro has an 8-bit upstream link and a 16-bit downstream link, both of which run at 600MHz.

HT analyzer on the K8T800

HT analyzer on the nForce3 Pro

With memory already local to the processor, a faster HyperTransport link should primarily affect AGP performance, along with other forms of direct-memory-access I/O.