So, I tried making my own attempt at measuring this by following the testing in the latest guide as close as possible. Scott doesn't detail the exact location and I messaged him, but didn't receive a response. After some sleuthing it turned out to be a run between Fields Waypoint and Orchard Waypoint, Shaemoor Fields, Kryta, following the road as closely as possible.
I set my settings for exactly the same as in in latest 7950 review. Interestingly enough LoD and Shadows weren't on their highest setting in the TR review. I left those the same as the TR example though.
I was originally going to do this in Gdocs since it would be quite easy for other people to access and parse at their own bidding, but as it turns out gdocs has issues with large sets of data (mine had 20k rows) and was slow as molasses.
So I ended up parsing it in Libre Office to make graphs and then did some analysis in SPSS.
Resolution was set at 1680x1050
Somethings to note: I'm on a populated realm so various people were wondering around in this zone. Occasionally a battle happened, but there was more of that in the 20% run through then the 0%. I left the camera at the default angle when warping into the point and ran from one end to the other, then back again. So I went over the road three different times, Fields > Orchard > Fields > Orchard.
Subjectively the system felt more responsive on +20% (but that's qualitative once again).
Std.dev is worse off on the +20% results, but that takes into account drops to lower frame times as well as higher ones (not just higher frames). Mean for +20 is lower as well as the min and max. The differences seem largely trivial, but a higher std. dev may be indicative of it being more responsive. The red line stepdown in the middle of the graph compared to the smooth one for blue was due to the way I spun around. I did a short burst with the +20 twice, compared to just holding down the turn key with the 0, this may also have influenced results.
It's quite hard to measure results like this in a live game, I'll have to try doing a circular run around one of the bigger cities tomorrow as cities seem to stress graphics more.