AMD FM2 Chipsets – A85X, A75, A55

Since it has been a while since the last time we looked at the FM2 chipsets, it’s worth a little recap.

With the release of the FM2 APUs, AMD has specified which processors they have targeted for which chipsets. According to AMD, the A55 chipset is targeted for use with the A4 and A6 series APUs. The A75 chipset is targeted for the A6 and A8 APUs and the A85X chipset targets the A8 and the A10 series APUs. There is a little bit of overlap there, as you can see.

Even though AMD touts the A85X chipset as targeting enthusiast and performance users, it really doesn’t bring a whole lot more onboard. The reason for that is that the APUs have most of their functionality built right into the processor. The old “northbridge” is now a function of the CPU and the A85X chipset is really just a functioning “southbridge”, now known as the Fusion Controller Hub (FCH). Since the APU controls almost everything, the FCH brings in the use of external controllers and connections.

The A85X chipset brings with the ability to use a second PCI-Express GPU slot. The total number of lanes remains the same, however, so if you use two PCI-Express slots for GPUs, you’ll be running at x8 and x8. Using a single discrete GPU, you’ll still be able to run it at x16 of course. In addition to adding the use of another PCI-Express slot, the A85X chipset brings with it a full complement of eight SATA III 6Gb/s ports. That’s up from six on the A75 chipset and zero on the A55 chipset. All the SATA ports on the A55 chipset are SATA II. With those SATA III ports also comes RAID 5 support, absent on the A75 chipset. The USB connectivity remains the same between the A75 and A85X chipsets with support for 4 USB 3.0 ports, 10 USB 2.0 ports, and 2 USB 1.1 ports.

The odd thing about AMD keeping the A75 and A55 chipsets with the FM2 socket is going to be the motherboard naming conventions. Just because a motherboard says it has an A75 chipset doesn’t necessarily mean that it is a Piledriver FM2 motherboard. It could be a Llano motherboard, supporting only FM1 APUs. Because of that, you’ll have to keep on your toes. I don’t expect too many A55 FM2 motherboards, but just beware that when you are searching for your next upgrade, if it doesn’t say FM2 or A85X, it may not support your Richland APU.