Before we started overclocking, we needed to see how the card performed out of the box. As expected, the Lightning XE proved very capable. In Dirt 2 the card produced a minimum frame rate of 80fps, even at 2,560 x 1,600 with 4x AA , making it 5 per cent faster than a standard GTX 580 1.5GB. However, the Lightning XE still lost out to the dual-GPU cards we tested.
In Black Ops we again saw a minimum frame rate of 80fps at 2,560 x 1,600 with 4x AA, which represents a speed advantage of 8 per cent over a standard GTX 580 1.5GB card.
Despite being a DirectX 9 title, Arma II is very demanding, and even with a super-high-end card such as the Lightning XE, we only saw a minimum frame rate of 29fps at 2,560 x 1,600 with 4x AA. This was still an improvement of over 10 per cent over a standard GTX 580 1.5GB - given that the overclock alone is between 3-8 per cent, it looks as if the extra video memory has helped with this game. In fact, it was fast enough to outpace a dual-GPU AMD Radeon HD 6990 4GB with its Antilles Unlocking Switch active.
Battlefield: Bad Company 2 also seemed to appreciate the extra video memory. At 1,920 x 1,080 with 4x AA, the Lightning XE produced a minimum frame rate of 59fps; a 40 per cent performance improvement over a stock GTX 580 1.5GB card despite the Lightning XE sporting an overclock of 3-8 per cent. We saw a similarly large gap between the two cards at 2,560 x 1,600 with 4x AA.
The Twin Frozr III cooler also did a great job of cooling the card. The peak delta T was just 40°C, despite the twin 90mm fans remaining extremely quiet throughout testing. Despite the overclock and extra power circuitry, power consumption was also a little lower than that of a stock GTX 580 1GB, with our PC only gobbling up to 330W from the wall.
We weren’t done yet, though, and were keen to see just how far we could push the Lightning XE when its voltages were laid bare for tinkering. Installing a beta version of MSI Afterburner developed for this card, we were able to reach a whopping 980MHz GPU core clock by adding an extra 165mV of GPU vcore - this is a 26 per cent increase over the 772MHz stock speed of a GTX 580 1.5GB, and far beyond any other GTX 580 1.5GB we’ve overclocked previously.
We also increased the memory clock to 1,250MHz - a 22 per cent increase over that of a stock GTX 580 1.5GB. These are the sorts of overclocks we’d expect from a GeForce GTX 560 Ti 1GB, so to see them from the much more complex GPU is very impressive indeed.
The overclock resulted in a minimum frame rate in Dirt 2 (at 2,560 x 1,600 with 4x AA) hit 95fps - a 19 per cent increase over the Lightning XE’s factory speeds. Arma II also saw tangible performance improvements, with the minimum frame rate at 2,560 x 1,600 with 4x AA rising 21 per cent from 29fps to 35fps. Meanwhile, Bad Company 2 saw a speed boost of 14 per cent at 2,560 x 1,600 with 4x AA; thanks to the 3GB of GDDR5 memory, the Lightning XE was 50 per cent faster than a standard GTX 580 1.5GB.
Colin McRae: Dirt 2 Overclocking
2,560 x 1,600 4x AA 16x AF, DirectX 11, Maximum Detail
All the extra power required for the overclock did have negative effects, though. Peak system power consumption hit 450W - an increase of over 100W from the card’s standard settings. The peak delta T also shot up, with the GPU running 52°C above ambient under load, while the fans became very noisy indeed. However, even after a big overclock and overvolt the Lightning XE's GPU was still 7°C cooler than that of a stock GTX 580 1.5GB card.
Overclocking Heat (peak)
Unigine Heaven Benchmark (1,920 x 1,080 4x AA 4x AF)