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
First off, the poorest value-for-money card is the GeForce GTX 285.
£300 for a GPU that barely outperforms the £200
GeForce GTX 275 says it all.
The aggregate score for the Sapphire Radeon HD 4890 OC Edition would
have - and should have - been higher than the slower-clocked XFX's if
not for slightly below-par performance in Race Driver: GRID. That said,
its HEXUS.bang4buck is reasonably competitive in the
£200-£250 space, but spending £260 on the
Sapphire Radeon HD 4850 X2 brings linearly greater performance benefits.
Update: 14/04/09. The price of the Sapphire Radeon HD 4890 OC card has now dropped to just over £200, including VAT. This makes it a far more attractive proposition than two weeks ago, obviously.
Overclocking
Launching at 901/4,000MHz, we pushed the Sapphire Radeon HD 4890 OC
Edition even higher, to an impressive 965MHz core and 4,700MHz GDDR5
memory - making the sample the most overclocking-friendly ATI Radeon HD
4890 yet. The card returned an average frame-rate of 83fps in Enemy
Territory: Quake Wars at 1,920x1,200, and this rose to 91.89fps when
overclocked.
