MSI K9A3 CF – RD780 motherboard



On the 20th of November AMD is due to release its Phenom X2, X4 and FX desktop processors and as surely as night follows day, that means that new AMD and nVidia chipsets will also hit the streets.

We’ll cover nVidia another day when we get our hands on an MCP72 but for the time being it’s AMD all the way. At the high-end we’ll have the AMD 790FX, which supports three or four graphics slots with next generation CrossFire. In the mid-range there’s RD780 which might be called AMD 780 or 790X, which supports dual graphics slots and following on some time later AMD will unveil a budget chipset along with various IGP models.

This MSI K9A3 CF uses an AMD RD780 chipset with SB600 Southbridge and despite rumours that SB700 would surface this year we don’t expect to see it until 2008. That may sound a bit disappointing, but SB700 is only expected to increase the SATA II count from four to six, while USB 2.0 support will rise from 10 to 12.

All of these new chipsets support Phenom but the specific technical feature that has been added is support for HyperTransport 3.0. As you can read here HT 3.0 extends the speed of HT 2.0 from 1.4GHz DDR to at least 1.8GHz or as high as 2.6GHz. The maximum bandwidth of HT 1.0 is 12.8GB/second rising to 22.4GB/second with HT 2.0 and now we have the prospect of up to 41.6GB/second with the new HT 3.0. No doubt AMD is hoping that HT 3.0 will unlock a bottleneck in quad-core performance that will allow Phenom to fly where the 1,333MHz FSB of Core 2 Duo restricts Intel’s finest to 10.66GB/second.

We’ll have to wait and see on that score as we don’t have a Phenom processor, and that also means that the MSI K9A3 CF won’t necessarily show its true colours in this review. Although an AM2+ motherboard is backwards compatible with an AM2 CPU you don’t get the benefit of the faster bus with the older processor.

For the record SiSoft Sandra reports that our Athlon 64 X2 6400+ CPU (linkout: is compliant with HT 1.02 while the Asus M2R32-MVP with Radeon Xpress 3200 chipset that we used for comparison purposes supports HT 1.05, which rather suggests that there aren’t any HT 2.0 desktop chipsets on the market so HT 3.0 effectively triples the bandwidth of the HyperTransport bus.

We were sent a bare MSI K9A3 CF (that’s CF for CrossFire) in a plain box with a driver CD but no manual, brackets or cables.

The layout of the K9A3 is very conventional and somewhat dull with the four DDR2 memory slots positioned between the processor socket and main power connector. By contrast the Asus M2R32-MVP takes advantage of the integrated memory controller in the Athlon 64 core and places the memory slots across the top of the motherboard.