Here are some #'s on a 2600k with and without HT. I believe the without HT would be the same as a 2500k but with 2 more mb's of cache? So if the difference is that much just between the 2600k with and without HT then I would assume it would at least be this much difference if not more between the 2600k and 2500k.
16.jpg
That's a pretty big difference on wprime and vantage. Wish there was one showing all the Bot point benches.