MSI's new GeForce GTX 580 Lightning Xtreme Edition builds on the success of the previous Lightning GTX 580. The only performance related difference is the inclusion of 3 GB of memory instead of 1.5 GB like on the successor. Unfortunately thoughout our testing this could not result in a significant performance increase. I could imagine there being some difference with super high AA settings and multi monitor gaming, but the raw GPU power will quickly be a limiting factor here. This does not mean that the card is slow by any means. It handled everything we threw at it with flying colors, 2560x1600 is the resolution you want to use this card on.
In terms of overclocking features, the GTX 580 Lightning brings pretty much a complete set. You can adjust voltages via DIP switch on the board (no software required) or using MSI's Afterburner OC software. When using subzero cooling, you have a special BIOS at your disposal that eliminates any "cold bug" problems and similar issues.
Surprisingly, the card does require less power than NVIDIA's reference GTX 580 which seems to be thanks to the low temperatures and the redesigned power circuitry. Unfortunately fan noise in load is quite high, I would have wished for a better optimization of noise and temps here.
Overall MSI's GTX 580 Lightning Xtreme Edition is a beast of a card, yet it fails to include real gamechanger features over MSI's "normal" GTX 580 Lightning Edition. If you are an overclocker, then both MSI's GTX 580 Lightning and GTX 580 Lightning Xtreme are cards that should be on your short list. Extreme cooling like dry ice and LN2 is welcome, too.