We've already written a fairly lengthy article about how confusing the notebook configurations for AMD's Dual Radeon Graphics configuration options are and trust us when we say that the desktop options don't make things any easier. AMD even has two different configuration tables depending on if we're talking a regular desktop or an all-in-one PC.
Let's start with regular desktop configurations. First of all the E-series processors don't work with Dual Radeon Graphics at all, so the lowest level of entry is the A4-series of APU's with Radeon HD 6410D (D for desktop we presume) graphics. The A4-series of APU's only works with the Radeon HD 6350 (DDR3) and the 6450 (GDDR5). Combine the APU with the 6350 and you get a Radeon HD 6430D2 and if you combine it with the 6450 you get AMD's recommended combination, the Radeon HD 6510D2. Higher-end cards will take over as discrete only solutions with no dual graphics option available.
Things are similar with A6 and A8-series as you can see from the table, although once again we have a setup where we get different D2 names, specifically if a Radeon HD 6570 is used as with an A6 APU this makes a Radeon HD 6610D2 whereas with an A8 APU this makes a Radeon HD 6630D2. Oddly enough using a Radeon HD 6450 or 6670 yields the same dual graphics naming for both APUs.
Move on to all-in-one systems and we're in for a whole other ballgame as here we all of a sudden have a fifth discrete GPU supported, the Radeon HD 6550. We're not sure what the A in the model names in the table signifies, but presumable it has something to do with AIO specific SKUs. The Radeon HD 6550 combines into a 6570A2 with an A4 APU, a 6590A2 with an A6 and finally a 6610A2 with an A8, confused yet?
There's no 6570 here, instead there's a higher-end 6650 option which alongside with a slightly different 6670 SKU (LP is traditionally for Low Profile desktop cards), both based on a different graphics core than the desktop and mobile 6600-series parts. Truth be told, we have no idea what the difference is here, but once again we end up with multiple combinations that don't quite add up in our heads. That said, on the mobile side a 6630M and an A8 makes a 6690G2 and on the AIO side of things the 6650 and an A8 makes a 6690A2 which is at least somewhat similar, if not exactly the same, or so we think.
At the end of the day, combining an A8 APU with the highest possible discrete solution according to AMD's charts you can end up with a 6990D2, a 6730A2 or a 6775G2 based on a desktop, AIO and notebook. Wouldn't it just have been easier if they all tallied up the same? AMD already has denominators for the various systems and we have a feeling it would at least have made somewhat more sense to see a more structured system even if the performance might not have been identical across the three platforms.
We also find it peculiar that the desktop platform has the smallest selection of combinations, as this is the only platform where the user has any kind of control over what he/she gets. Even more confusing AMD only recommends certain combinations and we're not sure if this rules out options like a Radeon HD 6570 with GDDR5 memory, something that can be purchased, but apparently doesn't fit AMD's profiles. We can't even begin to imagine how many angry support calls there will be from users trying to upgrade the graphics performance on their system if it turns out that certain memory on an otherwise supported graphics card isn't accepted as a viable option.
AMD, please fix this, it truly is a terrible mess and about as clear as mud. It's a great idea, but the way it seems to work really doesn't make a lot of sense and why is the upper limit on desktop GPUs in theory set lower than on notebooks? This could've been such a great way to upsell consumers, but now it's mostly just confusing. We don't have any high hopes for this being resolved any time soon, but fingers crossed AMD will at least provide detailed information to its customers about what works and what doesn't.