Lewis Hamilton was fastest again on the second day of testing at Paul Ricard.
The McLaren driver beat morning pacesetter Felipe Massa by 0.141 seconds, having lapped in 1:05.614 this afternoon.
Robert Kubica was third for BMW, ahead of David Coulthard and Takuma Sato.
The teams continued their work on Monaco preparations using a tight and twisty configuration of the High Tech Test Track, working in particular on the super soft tyres that will be used for the first time this season in Monte Carlo.
Although yesterday's strong winds had made it difficult to draw firm conclusions, the consensus from the teams was that while the super soft compound was too soft for the abrasive Ricard track, it should prove effective around Monaco. Today's running was less affected by the wind, although the breeze picked up again during the afternoon.
Honda introduced a significant aerodynamic upgrade at the test, with a new front wing, rear wing and sidepods. Rubens Barrichello was sixth fastest, although his quickest time was set using the original specification car. He lapped 0.5 seconds slower with the new package.
"I tried the upgrades, it seems more stable," he told autosport.com. "It is better, I think, and I think we are doing reasonable times."
He added that a lack of track knowledge was affecting his performance.
"The thing is I don't know the track," Barrichello said. "Ferrari hardly ever tested here so I (last) ran here with Jordan in '92! It was wet too!
"So I have re-learn the track. I have raced here in (Formula) Opel Lotus but that doesn't count."
Triple Champ Car champion Sebastien Bourdais made another appearance for Toro Rosso, and set the 10th fastest time.
Testing continues for two more days, but the circuit configuration will now be altered so that the teams can try low downforce settings in preparations for the Canadian Grand Prix next month.
Wednesday's testing times:
Pos Driver Team Time Laps
1. Hamilton McLaren-Mercedes (B) 1:05.614 133
2. Massa Ferrari (B) 1:05.755 107
3. Kubica BMW-Sauber (B) 1:06.185 140
4. Coulthard Red Bull-Renault (B) 1:06.201 137
5. Sato Super Aguri-Honda (B) 1:06.281 116
6. Kovalainen Renault (B) 1:06.302 161
7. Barrichello Honda (B) 1:06.516 103
8. Wurz Williams-Toyota (B) 1:06.576 106
9. R. Schumacher Toyota (B) 1:06.598 111
10. Bourdais Toro Rosso-Ferrari (B) 1:07.743 142
11. Albers Spyker-Ferrari (B) 1:07.946 66
12. Sutil Spyker-Ferrari (B) 1:08.134 67