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AMD's Radeon R7 260X graphics card reviewed

The second coming of Bonaire

Barely seven months have passed since AMD launched its $149 Radeon HD 7790. Today, the company is introducing a new, faster graphics card based on the same silicon: the $139.99 Radeon R7 260X.

AMD gave us an early peek at the R7 260X during its GPU14 press event in Hawaii. We now know much more about it. For example, we know that it improves upon the Radeon HD 7790 by raising the core and memory speeds and by doubling the amount of memory onboard. We know that it has some new features, and that, in a surprising twist, those same features were lying dormant inside the 7790's GPU silicon all along. We even know that driver updates will soon enable all of those features in the 7790.

And, of course, we have a whole boatload of benchmarks—inside-the-second numbers that tell us how the R7 260X stacks up against both its predecessor and its competitors.

(By the way, AMD is also cranking out a couple of higher-end cards today: the R9 270X and 280X. You can find Scott's review of them here.)

Bonaire's secrets
AMD's Bonaire graphics processor has been kicking around inside the Radeon HD 7790 since March, and all the while, it's been harboring some secret features. Behind closed doors at the GPU14 event, we learned that Bonaire is based on the same "IP pool" as Hawaii, the next-gen GPU scheduled to premiere inside the R9 290X later this year.

In short, Bonaire has many of the same architectural perks as Hawaii: improved shaders (which also appeared in the Kabini APU), embedded TrueAudio DSP cores, and greater flexibility when it comes to connecting multiple monitors. Bonaire also has the same power management mojo as Hawaii, but unlike the other features, AMD made that functionality public at the 7790's launch. You can read all about it in our 7790 review here.

Like Hawaii, Bonaire has shaders that support flat memory addressing and MQSAD (or masked quad sum of absolute difference) operations. With flat addressing, the idea seems to be to combine system and GPU memory into a single address space. This, among other things, should help facilitate the development of GPU computing applications.

Bonaire also supports AMD's new TrueAudio technology. Inside the GPU silicon are Tensilica HiFi EP Audio DSP cores, a streaming DMA engine, 384KB of shared internal memory, and a low-latency bus interface that ties the DSP cores to the GPU's frame buffer and main system memory. AMD doesn't say how many DSP cores there are, but it tells us they run at 800MHz, and it claims Bonaire and Hawaii have the same DSP config. That means the two chips should have the same audio processing capabilities, despite their being aimed at wildly different price points.

Thanks to TrueAudio, game developers will be able to implement advanced spatialization and reverb effects based on in-game geometry. At the GPU14 event, AMD demoed elevation and depth perception simulations on a 7.1-speaker setup. A 3D sound stage was also emulated using two speakers. The TrueAudio pipeline is programmable, so developers should have some freedom to tweak those effects and perhaps to use the DSPs for other things.

As we understand it, using specialized DSP cores is better than simply processing advanced audio effects in software, which can tax low-end CPUs and yield inconsistent performance. Crucially for audio, the specialized DSP approach also incurs lower latency than processing sound in GPU shaders via DirectCompute or OpenCL.

Lastly, Bonaire makes it easier to connect multiple displays. With previous-gen GPUs, triple-monitor configs wouldn't work unless one of the displays was hooked up via DisplayPort. That requirement has been lifted. Users can now, for example, connect two monitors via DVI and a third one via HDMI. Additionally, setting up five or six monitors no longer requires a graphics card with a corresponding number of outputs. Users can now daisy-chain displays or use a DisplayPort hub.

Those features are present in the R7 260X, and AMD says its current drivers enable the improved shaders and multi-monitor mojo in the Radeon HD 7790, as well. TrueAudio support will come to both cards later, in a driver update.

In the end, then, the R7 260X's only real advantages over the 7790 are its higher clock speeds and its larger frame buffer. The two cards have otherwise very similar specifications:

Radeon HD 7790 1000 896 56/28 16 6.0 GT/s 128 85W
Radeon R7 260X 1100 896 56/28 16 6.5 GT/s 128 115W

Those similarities are compounded by the fact that many, if not most, retail 7790s are clocked higher than the reference speeds you see above. AMD bragged about this fact earlier this year. It's not uncommon to see retail 7790 cards with peak GPU and memory speeds of 1075MHz and 6.4Gbps, respectively—quite close to the reference R7 260X.

The R7's larger frame buffer is a notable improvement, though. Variants of the 7790 cards with 2GB of memory do exist, but they're few and far between. Newegg carries only two of them right now: one priced at $139.99, and another at $169.99. The R7 260X will make 2GB of video RAM the new standard at $139.99. Given the slew of graphically intensive next-gen games coming later this fall, that's probably a good thing.