ITXGamer Archives

AMD’s Dual Graphics: Crossfire on a ITX System?

One of the biggest shortcomings that a mini-ITX gaming system faces is its lack of ability to support multiple GPUs. Between AMD’s Crossfire and Nvidia’s SLI, hardcore gamers can rock multiple video cards in their ATX systems for huge performance gains. Sometimes, gamers can even enjoy cost savings with a multi GPU setup. Two slower cards can be paired together to get the same performance as a high-end card, but at a lower price point. However, a mini-ITX system can’t take advantage of either the performance gain or the possible cost savings due to the nature of the format and it’s single PCI Express slot.

A possible solution is on the horizon. Five years ago AMD acquired ATI and began promising the world a new way to process graphics. They planned to combine an AMD CPU on the same chip with a Radeon GPU, effectively creating a single chip to function both as the system processor and the graphics processor.

The first retail version was the Brazos platform. Targeted for the HTPC crown and small form factor builders, the ITX gaming abilities were limited (although it easily beat the pants off  it’s main competitor). However, it did hint at the possibilities that would be forthcoming with the desktop-class version of the Vision platform, codenamed Llano.

With the new Llano chips now available and FM1 socket mini-ITX motherboards soon to follow, the big feature on the Llano APU’s that gets my attention is the Dual Graphics ability. No longer limited to a single GPU, what possible heights can a mini-ITX gaming system reach if it can now run multiple GPU’s in unison. Do we now have the possibility of Crossfire in our mini-ITX systems?

Not quite. According to a great review on TomsHardware, Dual Graphics may not always be your best bet. They put an AMD A8-3850 through the ringer and came to some interesting comparisons regarding the performance gains of the Dual Graphics system.

Here’s my take on their article.

It seems there is an extensive setup process required to ensure that the system doesn’t default to the slowest GPU installed, as it apparently does by default due to Llano APU wanting to provide the primary video outputs. But one you have completed the install, the system will default to the faster GPU and you’ll use the discrete output as the primary display.

AMD has also come up with an ‘equivalent GPU’ numbering scheme to give you some idea of where the combined perfomance of your multi-GPU setup will fall. In their example; the A8-3850 (HD 6550 Onboard) paired with a discrete HD 6570 gives you the equivalent of an HD 6630D2 (the D2 indicating that 2 GPU’s are being used to make the 6630). Considering AMD’s graphics numbering system, we can expect that the 6630 would slot above the 6570 on the performance chart.

But how did it really perform?

Tom’s took their new AMD Llano with its equivalent HD 6630D2 and ran it through three games (Metro 2033, Call of Duty: MW2 and WOW: Cataclysm) and compared it to a Core i3-2105 (similar price point) with the same discrete HD 6570 GPU and to the i3’s Intel HD GPU. The results are interesting.

First off, Dual Graphics and DirectX 9 don’t play together. Run a game with DX9 on your Llano ITX system and you won’t benefit from the Dual Graphics setup. You’ll get only the performance from the HD 6570, regardless of the CPU that you use.

Run a DirectX10/11 game on your system and you mileage will vary. In Metro 2033, the Dual Graphics are handily beat by the i3/6570 setup. Switch over to Cataclysm and the 6630D2 handily outperforms the i3 setup.

Games or settings don’t matter when comparing Llano to the Intel IGP. The AMD’s integrated Radeon flat out spanks the Intel HD in every situation.

So the short answer to our question is yes, we can have a multi-GPU setup in our mini-ITX gaming systems, although not quite in a true Crossfire setup. Whether or not it’s going to give us any real performance gains over our current builds appears to be largely dependant on what games we want to play.

But more importantly, now we can tell the disbelievers that yes, we’re rocking mini-ITX gaming systems with multiple GPU’s.