HEXUS.bang4buck and overclocking
In a rough-and-ready assessment of the cards' bang per buck, we've aggregated the 1,920x1,200 frame-rates for five 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 five different games, the cards' prices could have been derived from other sources and pricing tends to fluctuate daily.
Consequently, the table below highlights 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.
* 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 HEXUS.bang4buck score only takes the performance and price into account, of course.Analysis
Price is a wonderfully fickle thing and what you see above may not be representative of how much etailers will charge. Still, the three new cards, when evaluated over five games, performance at more-or-less the same levels, as shown by the aggregate and normalised scores. In reality, the GeForce GTX 275 beats out both the Radeon HD 4890s in three of the games, but poor performance in Race Driver: GRID brings it aggregate score down.
The weakest card of the trio, as far as the HEXUS.bang4buck is concerned, is the Radeon HD 4890 OC, which will cost at least 10 per cent more than the standard XT version but provides just three per cent extra (normalised) performance. That's true of most pre-overclocked cards, and we expect to see the same metric dip for GeForce GTX 275s.
Overclocking
| Graphics cards | NVIDIA GeForce GTX 275 896MB |
XFX Radeon HD 4890 OC XXX 1,024MB | Sapphire Radeon HD 4890 XT 1,024MB |
|---|---|---|---|
| GPU clock |
633 | 900 | 850 |
| GPU max | 721 | 920 | 940 |
| Percentage overclock | 13.9 |
2.22 |
10.59 |
| Memory clock | 2,268 | 3,900 |
3,900 |
| Memory max |
2,564 |
4,600 | 4,600 |
| Percentage overclock | 13.05 | 17.95 |
17.95 |
| ET: QW 1,920x1,200 | 88.5 | 82.3 | 79.45 |
| Overclock score | 99.53 | 89.73 | 88.23 |
| Percentage increase | 12.46 | 9.03 |
11.05 |
Somewhat counter-intuitively, the XFX Radeon HD 4890 OC's core didn't run as high as the XT version, and both squeaked past 900MHz without too much to spare. Memory overclocks on all cards are excellent, hinting at significant headroom for future partner-overclocked models.
The end result is that the trio of cards offer around 10 per cent extra frame-rate in Enemy Territory: Quake Wars when overclocked to a stable, safe limit. As the GeForce GTX 275 896MB is already the fastest of the bunch, it wins this test, as well.
