HEXUS.bang4buck and bang4watt
Putting all the numbers into perspective, let's take a closer look at overall performance.
In a rough-and-ready assessment of the cards' bang for buck, we've aggregated the 1,920x1,080 frame-rates for four games, normalised them* and taken account of the cards' prices.
But there are more provisos than we'd care to shake a stick at. We could have chosen four different games, the cards' prices could have been derived from other sources and pricing tends to fluctuate daily, especially for pre-release GPUs.
Consequently, the table below highlight a metric that should only be used as a yardstick for evaluating comparative performance with price factored in. Other architectural benefits are not covered, obviously.
| Graphics cards | Sapphire Radeon HD 5870 1,024MB | HIS Radeon HD 5850 1,024MB | HIS Radeon HD 5850 XF 1,024MB | HIS Radeon HD 6870 1,024MB | Sapphire Radeon HD 6850 1,024MB | Sapphire Radeon HD 6850 XF 1,024MB | HIS Radeon HD 5970 2,048MB | ASUS GeForce GTX 480 1,536MB | ASUS GeForce GTX 470 1,280MB | NV GeForce GTX 460 SLI 1,024MB |
KFA GeForce GTX 460 1,024MB | NV GeForce GTX 460 768MB SLI | EVGA GeForce GTX 460 768MB |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Aggregate FPS (1,920x1,080) |
244.6 | 208.5 |
343.6 |
222.2 |
194.3 | 341.1 | 334 |
305.1 |
204.8 |
348.9 |
197.1 |
333.6 | 185.9 |
| Normalised* FPS (1,920x1,080) |
214.1 | 170.15 |
291.8 |
183 |
150.85 |
289.05 |
287 |
260.35 |
201.35 |
291.55 |
145.05 |
277.5 |
131.05 |
| Current pricing | £275 | £200 | £400 | £175 | £150 | £300 | £430 | £350 | £200 | £300 | £150 | £250 | £125 |
| bang4buck (1,920x1,080) |
0.779 | 0.851 | 0.729 | 1.046 | 1.006 | 0.964 | 0.667 | 0.744 |
1.007 | 0.972 |
0.967 |
1.11 | 1.048 |
| GPU power consumption** | 139 | 117 | 257 | 126 | 97 | 221 | 238 | 244 | 204 | 331 | 169 | 299 | 130 |
| bang4watt*** (1,920x1,080) |
1.54 | 1.454 |
1.135 |
1.555 |
1.555 |
1.308 |
1.206 |
1.067 | 0.987 | 0.881 |
0.858 |
0.928 | 1.008 |
* the normalisation refers to taking playable frame rate into account. Should a card benchmark at over 60 frames per second in any one game, the extra fps count as half. Similarly, should a card benchmark lower, say at 40fps, we deduct half the difference from its average frame rate and the desired 60fps, giving it a HEXUS.bang4buck score of 30 marks. The minimum allowable frame rate is 20fps but that scores zero.
** the GPU power consumption is derived from subtracting a flat rate of 100W - indicating system power-draw without a card - from the Call of Duty: MW2 load figure. While this figure isn't solely indicative of power pulled by the GPU, as the CPU also throttles up, it's a better metric than using peak system-draw alone.
*** the HEXUS.bang4watt score is a crude measurement of how much normalised performance the GPU provides when evaluated against GPU power-draw that's shown in the table: the former is divided by the latter. We're using the peak power-draw numbers obtained by running real-world Call of Duty: MW2.
Evaluation
The performance of the Radeon HD 6850 in two-card CrossFireX is very similar to that exhibited by the Radeon HD 5850 XF and single-card HD 5970. The benefit with the new cards is twofold: significantly lower cost and reduced power-draw. Indeed, we see no compelling reason to look at the HD 5970 - unless you only have a single PCIe x16 slot in the system.Looking towards the green team, SLI scaling is also very sharp. The GTX 460 1,024MB SLI performs to about the same level as HD 6850 XF and, priced the same, has a similar bang4buck. Where it loses out is with respect to power-draw. The GTX 460 768MB cards' excellent performance is compromised by choppier performance at 2,560x1,600 - no doubt down to the smaller framebuffers.
