Win XP D: Drive - HUGE "Reserved System Space"?

Running Windows XP Pro SP3, Diskeeper 9 for defragging:

As you can see from the attachments, the C: drive has a very small reserved space (MFT/mirror) that is conceivably the 216 MB that Diskeeper reports for the MFT size.

My problem is the comparitively MASSIVE reserved space on D: (see attachment), although Diskeeper reports the MFT size as only 88MB. Megabytes, not gigs. That reserved space has got to be about 30 gigs.. for an 88 MB MFT?

The files on this D: drive are relatively few and massive, so there's no need for this much reserved space. How do I reduce it? I've already adjusted System Restore size to the minimum, disabled it entirely, disabled Hibernation, and also set this value to 1 in the registry: http://ask-leo.com/c000086.html. That 12.5% should be more than enough, plus I know how to defrag the MFT if it ever grows beyond that and becomes fragmented.

But nothing has made a difference in this "Reserved System Space" so far. What's left to try besides reformatting the drive? I don't exactly have a place to put that 150GB of data while I format. Thanks.