It won't help the drive's seek time, but it'll make the filesystem more efficient. Partitioning a drive so that you keep the OS, apps, and data separate also helps prevent fragmentation.
Assuming Windows 98 or Me, I usually set up a drive with a 2 GB FAT16 partition up front for the OS (FAT16 is faster than FAT32), then a big partition for programs, then a partition for data (make this one small if your data is word processing/e-mail/personal productivity; if you're into MP3s and other huge files, then make this one big at the expense of the data partition).
If you do a lot of Internet stuff, I usually add another partition at the end and redirect Web browser cache there, since that's extremely fragmentation-prone data.
The result will be a drive that doesn't get fragmented nearly as often, and when it does, it'll defrag a whole lot faster, which adds up to increased system performance, though it won't necessarily benchmark any faster. How the system feels and how often it has to get maintenance is more important than its benchmark scores.
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Dave Farquhar
author, <i>Optimizing Windows for Games, Graphics and Multimedia</i> (O'Reilly)
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