Crossfire Connectors & True Audio

So What Happened To The Crossfire Connector?

Starting with the Radeon R9 290, 290X and now the R9 295x2, the Crossfire bridge has disappeared. Obviously the X2 is bridged internally with the help of a 3rd party PCI Express controller (PLX) but you could place two cards and thus four GPUs into Crossfire mode, without applying a Crossfire bridge. The Crossfire bridge we all know and learned to love is slowly being phased out.

Why this move? Especially with standards like PCI-E Gen 3.0 there's plenty of bandwidth there, but even at Gen 2.0, it really should not be an issue. For the R290/290X/295x2 cards set up in Crossfire, PCIE Gen 3.0 is recommended. We'll be performing some bus flood tests over Gen 3.0 at a later stage. What if you do not have PCIE 3.0 compatibility? Well, depending on your montherboard chipset and processor, the bus will revert to Gen 2.0 which will probably not make more than a marginal difference as it is really hard to flood even two x8 Gen 2.0 ports. BTW, it is a myth that Crossfire with 290, 290X and 295 X2 cards would not work on Gen 2.0 slots.

True Audio

AMD presented the following as a pretty big feature. Thus far however this new feature has been received with a bit of skepticism as most enthusiast PC users already have a dedicated soundcard. Anyhow, audio immersion is a key factor for AMD as they are now implementing an audio pipeline into the newest GPUs. Now first, please understand that AMD True Audio only is available on the R7 260X and the Radeon R9-290, R9-290X and R9-295x2. Next to that, future products based on new silicon will get this as well. But NOT the rest of the R7/R9 series as those products are respins of older GPUs like Pitcairn and Tahiti. 

You guys know programmable shaders for visuals, right? To some extent that now applies for audio as well; to improve audio effects (real-time voices and audio channels in your game opposed to what is possible with CPUs today) enabling directional (surround) audio over input. To do so AMD injected DSPs into the GPU that can do some magic on the audio channels. 

For the geeks:

• There are multiple Audio optimized DSP cores
• Tensilica HiFi2 EP instruction set
• Tensilica Xtensa SP Fload support
• The DSPs have 32 KB instruction and data caches
• 8 KB of scratch RAM for local operation.

So yes, an audio processor is onboard the R7 260X and the Hawaii based GPUs. For example surround with stereo could be virtualized. There isn't enough CPU power left to run complex audio mechanisms and this is where the technology kicks in. So professional grade audio is now closer to the PC with this new audio technology. Try to imaging High Quality Reverbs, Room Simulation True 3D audio dedicated audio processing. Game developers can use what is called a Wwise audio plugin to get all this going over the AMD True Audio DSP. This is going to help with CPU load. A few simple Audio effects can use up-to 14% of your CPU, this is now offloaded to the graphics card.