"would using boot time defrag in Diskeeper 7 destroy any gains by Boot Vis"
The purpose behind any defragmenter that performs a boot time defrag (PerfectDisk, Diskeeper, O&O Defrag) - is to defragment files that can not be defragmented online. This includes the pagefile, hibernate file, directories on FATx partitions, and metadata files on NTFS partitions. Boot time defrags are something that are typically NOT performed on a frequent basis. What we recommend to our customers is to perform a boot time defrag and then run BootVis. I don't know what the Diskeeper folks recommend to their customers.
- Greg/Raxco Software
Disclaimer: I work for Raxco Software, the maker of PerfectDisk, a commercial defrag utility, as a systems engineer in the support department.