|MSI A75MA-G55 AMD FM1 Llano Motherboard|
|Reviews - Featured Reviews: Motherboards|
|Written by Hank Tolman|
|Sunday, 11 September 2011|
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AMD A-Series A75 Fusion Chipset
In case you aren't familiar with the still-relatively-new A-Series Fusion Chipsets released by AMD, here is a refresher on what they are all about. I focus here on the A75 chipset, but the A55 chipset is overviewed as well.
The A75 FCH is one of a pair that was launched with the Fusion for desktop release. The A55 FCH is the other. Both platforms support the new socket FM1 APUs and have almost all of the same features. With the Sandy Bridge release, we found ourselves with two very distinct platforms, one supporting the on-die graphics, the other allowing for limited overclocking. With the Fusion launch, the A55 FCH just seems like an antiquated and outdated version of the A75 FCH. I have to be honest, I'm not really sure what the purpose of the A55 FCH is, except that it is used in a lot of notebooks. The A75 motherboards can be found from near $100, so they are at a good price point, and the few differences between the two ensure longevity and expandability.
The reason I call it antiquated is because of the features differentiating the A75 FCH and the A55 FCH. There are really only three. The first, and most shocking, difference is the lack of native SATA 6Gb/s functionality on the A55 FCH. The reason this is shocking is that SATA 6Gb/s has been a standard since the 890 Chipset and has even been an add-in due to third-party controllers since before that. I'm not really sure why AMD would leave it off of any of their newer chipsets. Granted, the need for SATA 6Gb/s ports is still low, as is the availability of devices that take advantage of the higher transfer rates. But things don't stay the way they are for long in the computer hardware industry and limiting yourself to SATA 3Gb/s is a good way to ensure yourself slower speeds in the near future. Undoubtedly, many of the motherboard manufacturers will include SATA 6Gb/s capabilities through the use of a third-party controller. Or maybe they won't. That would cost them more money, and with the price of the A75 motherboards already pretty low, why bother?
The second difference is in the USB ports. Both the A55 and the A75 FCH offer two USB 1.1 ports, very outdated but still useful. They also offer a wide array of USB 2.0 ports. The A75 chipset offers up to ten USB 2.0 ports while the A55 offers up to fourteen. Those four extra that are included with the A55 FCH is made up by the four native SuperSpeed USB 3.0 ports that are available on the A75 chipset. The A55 offers no native USB 3.0 compatibility. This isn't quite as shocking, considering none of the Sandy Bridge motherboards offer native USB 3.0 capabilities. All that means, really, is that a third-party controller has to be used. But again, with the price of the A75 motherboards, what is the point?
The final difference between the A55 and A75 chipsets is also related to the SATA ports. The SATA ports on the A75 FCH can utilize FIS Based Switching, while those on the A55 FCH cannot. This difference is the least concerning because it probably won't affect most users. FIS switching basically splits the bandwidth of a single SATA port so that you can utilize more than drive on a single port. Remember the IDE/PATA days where we hooked up multiple devices on a single port? This is similar. Hooking up two devices onto a single SATA 6Gb/s port would effectively split its bandwidth, giving you, essentially, two SATA 3Gb/s ports. That's not exactly true, because FIS based switching chooses how to allocate the available bandwidth. It's more like an external USB hub that you power off a single USB port from your computer.
I suppose what they technically means is that you could have up to a total of 12 SATA 3Gb/s lanes on the A75 FCH. I am a little unclear on exactly how many times the FIS Based Switching could potentially split the available bandwidth from a single SATA 6Gb/s port, but the potential for a lot of devices is there. I'm not sure how many users interested in the A75 chipset would need more than 6 SATA devices in the first place, but it does speak to the possibility of a very large home server of sorts.
Everything else about the chipsets is identical. The APU itself controls, of course, the GPU and the Memory Controller in addition to the CPU. The DDR3 RAM supported by the socket FM1 APUs includes speeds up to 1866MHz not overclocked. This is certainly more compatibility than the Sandy Bridge CPUs, which only support up to 1333MHz DDR3 RAM. The APU also houses support for a single PCIe x16 lane and four PCIe x1 lanes. Naturally, the APU controls the capabilities of the GPU, which include the legacy VGA in addition to HDMI and DVI. The APU is linked to the FCH through a Unified Media Interface with a bandwidth of 2GB/s.
The FCH (both the A55 and the A75) offers a few more additives, similar to what you find in a Southbridge, were this a legacy motherboard. The FCH controls another four PCIe x1 lanes, the 16 total USB ports (in their varying capacities), the SATA ports, the Audio controller, and the PCI port. A couple of interesting add-ins include an SD controller, an IR controller, and a controller for the APU Fan.