World champion Lewis Hamilton suffered a crash as Nick Heidfeld went quickest on the final day of testing at Jerez in Spain.
Briton Hamilton improved from seventh of eight cars on Wednesday to third of six on Thursday as rain hit the circuit in the morning and wind buffeted the cars throughout the day.
BMW Sauber's Heidfeld posted a fastest lap of 1:20.052 and completed the most of any driver, 123. He was three-tenths of a second quicker than Kimi Raikkonen, who managed 112 laps in the Ferrari F60.
Hamilton was more than a second slower than Heidfeld and, after being interrupted on the penultimate day, again suffered a truncated session when he crashed backwards and damaged the rear wing of the MP4-24 after losing control due to a powerful gust of wind. He completed 58 laps of the track.
Following him were Mark Webber of Red Bull and Williams driver Kazuki Nakajima, with Jarno Trulli bringing up the rear after recording only 38 lap-times having damaged his front wing.
Red Bull driver Sebastian Vettel's 1:19.055 on Sunday was the fastest time of the week by a huge seven-tenths of a second.
There will be another group test next week in Barcelona.
Testing times on Thursday:
1 . Nick Heidfeld (BMW Sauber) 1:20.052 - 123 laps
2 . Kimi Raikkonen (Ferrari) 1:20.414 - 112
3 . Lewis Hamilton (McLaren) 1:21.272 - 58
4 . Mark Webber (Red Bull) 1:22.219 - 47
5 . Kazuki Nakajima (Williams) 1:22.226 - 54
6 . Jarno Trulli (Toyota) 1:23.119 - 38
Jonathan Symcox/Eurosport