Thanks to Th3M1ghtyD8, for telling us here, about the review he found here. There is also an interesting read on this here.

"We have seen throughout our testing that were the enhanced level 2 cache is utilised the XP3000+ does indeed warrant its performance rating. The XP2800 despite running at a faster true speed is beaten by the XP3000+ in all of the real applications we tested, only losing out in the theoretical tests. When the XP3000+ is run at the same speed as the XP2800 the Barton core wins or is equal across the board. Although the performance gains are not a big as was hopped, the XP3000+ continues to improve on the Athlon’s performance."

More here, and comments here.