Is this Process to increase hard drive speed Safe? I

See here for a more detailed explanation of this "Advanced performance" option:
http://windowstipoftheday.blogspot [...] mance.html

Basically it causes agressive write buffering in the RAM, which can certainly speedup your system by writing the first X MB to the RAM first, making small file transfers complete very quickly even though the information is still being tranfered to the harddrive in the background; it would appear that the operation had already completed. This is known as write-back. There is one problem: a crash (blue screen) or power failure may cause severe file system corruption, causing data loss. So you should only use this on systems where you can easily restore a backup of the information should this situation occur.

Anti-virus and many Vista functions like auto-defrag, Indexing and System Restore, might slow down your computer, sometimes the Anti-Virus is amplifying this effect since it will scan each file Vista wants to index, so it becomes a real wear on your computer performance. You can disable these services, and benchmark your disk to see how its performing. Also, for true performance you need an SSD. Powerful modern systems with quadcores can still be limited by mechanical harddrives with high latencies; only the use of SSD as a system disk can break this performance barrier and give you a more fluent computing experience.

"Is this Process to increase hard drive speed Safe?"
No.