He speed soloed the Colton-Macintyre route on the Grandes Jorasses in a ridiculous 2 hours and 20 minutes. His record for the Eiger North Face is 2 hours and 47 minutes and his record for the North face of the Matterhorn is a mind bending 1 hour and 56 minutes. Less than 2 hours!
Aided by experts from the Swiss Olympic team, his body is at peak physical fitness which, it seems, allows him to not feel lactic acid build up and for him to literally run up these alpine faces
Steck is no slouch on rock either, having soloed several routes of F8a. His recent honeymoon to Yosemite was also productive - see this UKC News Report.
UKC contributor, professional photographer and all-round good bloke Jon Griffith puffed and panted his way up the Grandes Jorasses with Steck just a few days after the ascent. He captured some stunning photographs and also filmed Steck in action. Jon wasn't there on the day of the actual speed solo.
You can find out more about Ueli's ascent of the Colton Macintyre in this full detailed account: Alpine Exposures