The Table of Doom
| Graphics cards | ATI Radeon HD 5870 1,024MB | ATI Radeon HD 5850 1,024MB | ATI Radeon HD 5830 1,024MB | ATI Radeon HD 6870 1,024MB | ATI Radeon HD 6850 1,024MB | NVIDIA GeForce GTX 480 1,536MB | NVIDIA GeForce GTX 470 1,280MB | NVIDIA GeForce GTX 465 1,024MB | NVIDIA GeForce GTX 460 1,024MB | NVIDIA GeForce GTX 460 768MB |
|---|---|---|---|---|---|---|---|---|---|---|
| Transistors | 2.15bn | 2.15bn | 2.15bn | 1.75bn | 1.75bn | 3.0bn | 3.0bn | 3.0bn | 1.95bn | 1.95bn |
| Die size | 334mm² | 334mm² | 334mm² | 255mm² | 255mm² | 529mm² | 529mm² | 529mm² | 368mm² | 368mm² |
| General clock | 850MHz | 725MHz | 800MHz | 900MHz | 775MHz | 700MHz | 607MHz | 607MHz | 675MHz | 675MHz |
| Shader clock | 850MHz | 725MHz | 800MHz | 900MHz | 775MHz | 1,401MHz | 1,215MHz | 1,215MHz | 1,350MHz | 1,350MHz |
| Memory clock | 4,800MHz | 4,000MHz | 4,000MHz | 4,200MHz | 4,000MHz | 3,696MHz | 3,348MHz | 3,206MHz | 3,600MHz | 3,600MHz |
| Memory interface and size | 256-bit, 1,024MB, GDDR5 | 256-bit, 1,024MB, GDDR5 | 256-bit, 1,024MB, GDDR5 | 256-bit, 1,024MB, GDDR5 | 256-bit, 1,024MB, GDDR5 | 384-bit, 1,536MB GDDR5 | 320-bit, 1,280MB GDDR5 | 256-bit, 1,024MB GDDR5 | 256-bit, 1,024MB, GDDR5 | 192-bit, 768MB, GDDR5 |
| Memory bandwidth | 153.6GB/s | 128GB/s | 128GB/s | 134.4GB/s |
128GB/s | 177.4GB/s | 133.9GB/s | 102.6GB/s |
115.2GB/s |
86.4GB/s |
| Shaders | 1,600 | 1,440 | 1,120 | 1,120 | 960 | 480 | 448 | 352 | 336 | 336 |
| GFLOPS | 2,720 |
2,088 | 1,792 | 2,016 | 1,488 | 1,345 | 1,089 | 855 |
907.2 |
907.2 |
| Texturing | 80ppc
bilinear 40ppc FP16 |
72ppc
bilinear 36ppc FP16 |
56ppc
bilinear 28ppc FP16 |
56ppc
bilinear 28ppc FP16 |
48ppc
bilinear 24ppc FP16 |
60ppc
bilinear 30ppc FP16 |
56ppc
bilinear 28ppc FP16 |
44ppc
bilinear 22ppc FP16 |
56ppc
bilinear 28ppc FP16 |
56ppc
bilinear 28ppc FP16 |
| ROPs | 32 |
32 | 16 | 32 | 32 | 48 |
40 |
32 |
32 |
24 |
| GPixels/s | 27.2 | 23.2 | 12.8 | 28.8 | 24.8 | 33.6 |
24.28 |
19.424 |
21.6 |
16.2 |
| GTexel/s bilinear | 68 |
52.2 | 44.8 | 50.4 |
37.2 | 42 |
33.99 |
26.71 |
37.8 |
37.8 |
| Board power (max) | 188W | 151W | 175W | 151W | 127W | 250W | 215W | 200W | 160W | 150W |
| Multi-GPU | Four-way XFire | Four-way XFire | Four-way XFire | Two-way XFire | Two-way XFire | Three-way SLI | Three-way SLI | Three-way SLI | Two-way SLI | Two-way SLI |
| Board length | 11in | 9.5in | 11in | 9.5in | 9in | 10.5in | 9.5in | 9.5in | 8.25in | 8.25in |
| Outputs | 2x
dual-link DVI HDMI, DisplayPort, |
2x
dual-link DVI HDMI, DisplayPort, |
2x
dual-link DVI HDMI, DisplayPort, |
SL+DL
DVI HDMI, 2x DisplayPort, |
SL+DL
DVI HDMI, 2x DisplayPort, |
2x
dual-link DVI Mini-HDMI |
2x
dual-link DVI Mini-HDMI |
2 x dual-link DVI Mini-HDMI | 2 x dual-link DVI Mini-HDMI | 2x
dual-link DVI Mini-DisplayPort |
| Retail price | £295 | £215 | £165 | £189+ | £150+ | £360 | £200 |
£170 |
£160 |
£125 |
Analysis: Radeon HD 6870 1,024MB
Discussions on architecture are somewhat moot without a good look at the speeds and feeds. Let's put the Radeon HD 6870 into context by looking directly at the Radeon HD 5870.
First off, as we have indicated previously, Radeon HD 6870 is a significantly smaller chip. The transistor-count drops by almost 20 per cent and the die is reduced by almost 25 per cent. What this means is that, ceteris paribus, the HD 6870 is plain cheaper to produce on the same 40nm process as Radeon HD 5870, and this fact is the main reason why the Radeon HD 6870 will be a little cheaper than the Radeon HD 5850 and HD 5870 cards.
Jumping around the table, a smaller die leads to lower power-draw, down from 188W to 151W. Pragmatically, while HD 6870 still requires two six-pin PCIe connectors, coolers will be in the same vein as the HD 5850.
Shading power is much lower on HD 6870, though, as it's equipped with 1,120 stream processors - the same as HD 5830 - clocked in at 900MHz. The math tells us that it faces a 25 per cent deficit when up against HD 5870 in this regard. The good news is that the high core frequency and a Cypress-matching 32 ROPs keep pixel throughput at decent levels, while texture throughput is also more like HD 5850 - both share a GPU-wide 56 units.
Memory bandwidth sits between HD 5870 and HD 5850, so on paper, without factoring in the benefits of an improved tessellation engine and other minor AA/AF performance-related tweaks, one would surmise that it should benchmark between the two HD 5800-series cards. Should that indeed be the case, a retail price of £190, once the furore of launch-day pricing dies down, will make it a solid proposition.
Analysis: Radeon HD 6850 1,024MB
The Radeon 6850 card should arrive with a retail price of around £150. Based on the same core as the HD 6870, the cheaper GPU drops shaders from 1,120 to 960 - 14 SIMD engines to 12 - reduces the core frequency from 900MHz to 775MHz, and memory speed from 4.2GHz to 4.0GHz.
Add the numbers up and a sensible guesstimate predicts that HD 6850 will provide around 85 per cent of the performance of its bigger brother. The positive trade-off here is a lower street price, obviously, but also a lower card TDP - down to 127W - enabling AMD to get away with using a single six-pin PCIe connector.
Conjecturing before we see the benchmarks, the HD 6850 should beat the HD 5830 with ease and, looking at the other side, give the GeForce GTX 460 1,024MB GPU a good go.
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