The A55 and A75 Chipsets
As we mentioned in our introduction, the Llano platform at launch will consist of two chipsets from AMD - the A55 and A75. Before we move onto the Lynx APU itself, let's first take a closer look at exactly what's on offer from these two chipsets. To say that both chipsets are similar would be an understatement; they're near identical except for three features.
The first is FIS Based Switching in regards to eSATA. What's FIS Based Switching? Well, Wikipedia will tell you this - "FIS-based switching is similar to a USB hub. In this method of switching the host controller can issue commands to send and receive data from any drive at any time. A balancing algorithm ensures a fair allocation of available bandwidth to each drive. FIS-based switching allows the aggregated saturation of the host link and does not interfere with NCQ".
Translated to plain English for people, it essentially means that you're able to multiply eSATA connectivity off the single eSATA port. Think of a USB hub, but instead of a single USB port going out to four more USB ports, you have a single eSATA port that goes off too four more eSATA ports, or whatever number you have off your hub, or as it's known as here, port multiplier.
The chances are it's not going to be something that bothers you all that much. Unless you're a big eSATA user and find yourself wishing you had even more eSATA ports, it's probably not going to bother you. None the less, it's one of the main differences between the two chipsets.
Staying on the topic of hard drives, one of the big differences between the two platforms is the SATA speed. While both offer six SATA ports natively, the A55 is only 3 GB/s or SATA II, while the A75 is 6 GB/s or SATA III. As we see more and more hard drives offer SATA III, it's a big difference and the chances are it's going to be what sways you the most when it comes to choosing one chipset over the other.
Finally, we come to the USB ports. Again, like the SATA ports, we see that both chipsets offer us a total of 16 USB ports natively. The difference again comes down to speeds, though. While the A55 offers us two USB 1.1 ports and 14 USB 2.0 ports, the A75 offers us the same two USB 1.1 ports, but only 10 USB 2.0 ports with the other four ports being natively supported USB 3.0 ones.
Native USB 3.0 support on the AMD A75 chipset is something that's really cool, but it's worth knowing that we will probably see A55 boards with USB 3.0 connectivity via the well-known USB 3.0 controllers like ASMedia and NEC. For this reason we probably won't see the native support sway someone to one chipset over another.
Personally, I'd pick up native support over support via a separate controller any day of the week, but more than likely what will sway people is the cost associated with either chipset or the addition of native SATA III ports. Like the USB 3.0 situation, though, we could see an A55 board offer us both USB 3.0 and SATA III; it would be via a separate controller, though. Native is always going to be your primary option for the simple reason being it's normally faster as it's not going through anything else path wise.
None the less, those are the three main differences between chipsets and they will be what sway you to choosing one chipset over the other outside of the normal price argument.
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