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Texture filtering
We'll begin with a series of synthetic tests aimed at exposing the true, delivered throughput of the GPUs. In each instance, we've included a table with the relevant theoretical rates for each solution, for reference.

Peak pixel
fill rate
(Gpixels/s)
Peak
bilinear
filtering
int8/fp16
(Gtexels/s)
Memory
bandwidth
(GB/s)
Radeon HD 5870 27 68/34 154
Radeon HD 6970 28 85/43 176
Radeon HD 7970 30 118/59 264
Radeon R9 280X 32 128/64 288
Radeon R9 290X 64 176/88 320
GeForce GTX 770 35 139/139 224
GeForce GTX 780 43 173/173 288
GeForce GTX Titan 42 196/196 288

Although the 290X has, in theory, much higher fill capacity than the Titan, this test tends to be limited more by memory bandwidth than anything else. None of the GPUs achieve anything close to their peak theoretical rates. The 290X's additional ROP power will more likely show up in games using multisampled anti-aliasing.

The back-and-forth here is kind of intriguing. 3DMark's texture fill test isn't filtered, so it's just measuring pure texture sample rates, and the Titan manages to outperform the 290X in that test. The results from the Beyond3D test tool are bilinearly filtered, and in the first of these, the 290X takes the top spot.

Once we get into higher-precision texture formats, a major architectural difference comes into play. Hawaii and the other Radeons can only filter FP16 texture formats at half the usual rate. Even the GK104-based GTX 770 is faster than the 290X with FP16 and FP32 filtering.

In all cases, though, the 290X offers a nice increase over the Radeon R9 280X—which is just a re-branded Radeon HD 7970 GHz Edition, essentially.

Tessellation and geometry throughput

Peak
rasterization
rate
(Gtris/s)
Memory
bandwidth
(GB/s)
Radeon HD 5870 0.9 154
Radeon HD 6970 1.8 176
Radeon HD 7970 1.9 264
Radeon R9 280X 2.0 288
Radeon R9 290X 4.0 320
GeForce GTX 770 4.3 224
GeForce GTX 780 3.6 or 4.5 288
GeForce GTX Titan 4.4 288

I'm not sure what to make of these results. I expected to see some nice gains out of the 290X thanks to its higher rasterization rates, but the benefits are only evident in TessMark's x16 subdivision mode and with our low-res/extreme tessellation scenario in Unigine Heaven.

A couple of potential explanations come to mind. One, TessMark uses OpenGL, and it's possible AMD hasn't updated its OpenGL drivers to take full advantage of Hawaii's quad geometry engines. Two, the drivers could be fine, and we could be seeing an architectural limitation of the Hawaii chip. As I noted earlier, large amounts of geometry amplification tend to cause data flow problems. It's possible the 290X is hitting some internal bandwidth barrier at the x32 and x64 tessellation levels that's common to GCN-based architectures. I've asked AMD to comment on these results but haven't heard back yet. I'll update this text if I find out more.

Shader performance

Peak
shader
arithmetic
rate
(tflops)
Memory
bandwidth
(GB/s)
Radeon HD 5870 2.7 154
Radeon HD 6970 2.7 176
Radeon HD 7970 3.8 264
Radeon R9 280X 4.1 288
Radeon R9 290X 5.6 320
GeForce GTX 770 3.3 224
GeForce GTX 780 4.2 288
GeForce GTX Titan 4.7 288

Welp. This one's unambiguous. That massive GCN shader array is not to be denied. The 290X wins each and every shader test, sometimes by wide margins.

Now, let's see how these things translate into in-game performance.