Significantly slower? The W08 was better than the SF70, no doubt about that but the Ferrari "wasnt signifcantly slower on most tracks ", there were a lot of tracks where Ferrari was capable to keep up with Mercedes or was even faster in races but the issue was qualifying speed (15 vs 5 poles) espacially with the current cars which makes overtakes on tracks difficult - Ferrari had the better chassis and Mercedes the better engine and reliabilty. According to AuMS, Ferrari was faster than Mercedes in following races - Australia, Bahrain, Russia, Monaco, Hungary, Belgium, Singapore, Malaysia and Mexico, then you have races like Spain and Brazil where they were evenly matched and the other 9 tracks where Mercedes was faster- race pace it was evenly matched but like I mentioned, qualifying speed was the problem (-0.179 for Mercedes).