AMD Hybrid CrossFire Preview: Making Two Slow GPUs... Not So Slowby Anand Lal Shimpi on December 13, 2007 9:00 AM EST
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There are two types of graphics that do a horrible job at running the latest 3D games: integrated graphics, and low-end discrete GPUs. The problem is that a gamer who actually wants to play something like Unreal Tournament 3 or Crysis can't do so on either of the aforementioned solutions, and if he/she only has $70 to spend on a GPU, that's unfortunately not going to be enough to solve their problem. ATI and NVIDIA have always argued that users of such low-end graphics aren't hardcore gamers and thus don't mind not being able to play the latest games. We would counter that they're not likely to become hardcore gamers because they can't play the games, but we'll save that debate for another day.
Much of the very low-end discrete graphics market exists because of Intel, believe it or not. Since Intel ships the vast majority of integrated GPUs, and since its integrated GPUs don't perform all that well, the market is ripe for both ATI and NVIDIA to step in and offer something slightly better, for minimal cost. However, Intel recently committed to accelerating its integrated graphics roadmap, resulting in much faster integrated GPUs over the coming years. This puts additional pressure on AMD/ATI and NVIDIA to increase the value of their low-end GPUs.
AMD's solution to adding value to both integrated and low-end discrete graphics is through what it is calling Hybrid CrossFire. During today's Analyst Day, AMD will be unveiling a very limited amount of information about Hybrid CrossFire and thus we're able to talk about some of the high-level details today.
Hybrid CrossFire works by allowing you to run integrated graphics and low-end discrete graphics in CrossFire (multi-GPU) mode, thus improving the overall performance. You're basically taking two horribly slow GPUs and making one not-so-slow GPU. Obviously, this will only work with AMD graphics and AMD chipsets, but the idea is an interesting one - it could very well improve the value seen in both integrated graphics and low-end discrete graphics, should the performance gains be significant enough. It also gives AMD a reason to sell you an AMD chipset and an AMD graphics card.
AMD insists that Hybrid CrossFire can take a game that's unplayable on a low-end graphics card, and make it playable thanks to the added horsepower of the integrated GPU.
Hybrid CrossFire requires two components: a Hybrid CrossFire chipset and supporting graphics card. The chipset part is the forthcoming RS780, a successor to the AMD 690G and an integrated graphics version of the AMD 790 chipset. The RS780 will ship with an integrated RV610 graphics core, the heart of the ATI Radeon HD 2400 Pro. AMD insists that the RS780G's integrated graphics is fundamentally unchanged from the Radeon HD 2400, so we should expect a similar level of performance (AMD estimated 3 - 4x the 3DMark '06 score of the 690G, but gave no information on actual gaming tests).
Unfortunately, the first incarnation of Hybrid Crossfire with the RS780 will only really work with the upcoming Radeon HD 3400 series GPUs. If you stick a Radeon HD 3400 card (the 3450 and 3470 will arrive early next year), both the integrated RV610 graphics and the Radeon HD 3400 will work in tandem during 3D games. Where possible the two will employ a basic AFR CrossFire mode where each GPU is responsible for rendering its own frame. Since the two GPUs should be relatively well matched in terms of performance, load balancing shouldn't be a major problem. AMD told us that it has seen an increase in performance of anywhere from 40 - 70% in games like Unreal Tournament 3, Crysis and Call of Duty 4. We didn't receive any more guidance on performance.
The performance aspect of the technology won't work with any other cards, not to mention that there wouldn't be a performance benefit from running a Radeon HD 3870 and lowly RS780 integrated graphics in CrossFire. Hybrid CrossFire will allow you to have multi-monitor support across your integrated and discrete GPUs however.
The announcement gets even less exciting when you realize that the biggest feature of Hybrid CrossFire, the ability to power down your discrete graphics and only use integrated graphics in non-gaming scenarios, won't be delivered in the first version of the platform. While AMD mentioned that the power savings feature may be something we'll see in 2008, it's definitely not making its way out in the first release.
The power savings potential for Hybrid CrossFire is tremendous; even with the most aggressive power management we see on GPUs today, cards like the Radeon HD 3870 and GeForce 8800 GTS still waste a lot of power when not playing 3D games. Future versions of Hybrid CrossFire would allow you to switch to low power integrated graphics when you didn't need the performance of your discrete card, thus completely turning off power to the power hungry add-in GPU and relying on integrated graphics for basic video needs (e.g. Windows desktop).
The idea is that you'd get your video output from your integrated GPU, the add-in card would simply act as an accelerator driving data to the output on the motherboard. The future for technologies like Hybrid CrossFire is exciting. Expect to see Hybrid CrossFire with RS780 boards starting in late January for the Chinese market, and by March for the rest of the world.