Try of Momentus XT
Got this drive installed today, no issues on setting it up, 588GB of space on DVR (1Terrabyte drive is 745GB)
Haven't notice any real performance speedups, other than I think its a little faster on setting up multiple recordings one after another. Thats is while in guide push record on a program, hit right arrow to go to next program in guide and push record again I didn't notice any lag in getting to next program and the Scheduling bar that shows in top right side of screen going left to right seems to move quicker. As well I think the guide filled and loaded quicker after the Factory Reset, but not the sort of thing you can run a stop watch on.
Not a lot different than a regular 7200rpm drive I would say.
However these drives supposedly get faster as time goes on, but that's in say a W7 computer, perhaps things would change as DVR fills with recordings
I'll probaby keep it in for a week or so an go back an forth between my regular drive and this one to see if anything further shows up.