Strangely, I was reading on the wineq2 wiki last night about this very question. It said that 99% of the time having multiple installs wont make it faster. You can use wineq2 to have custom ini files for each character so that you can utilize different clip plane settings on different characters, turn sound on/off, etc.
http://www.lavishsoft.com/wiki/index.php/FAQMake individualized ini files per character by right clicking on the wineq2 system tray icon-->options-->preferences-->profiles-->"Character_name_01"-->EQClient.ini
If you're looking to improve performance I suggest trying the Underfist client. It uses about 20% less ram for me than Titanium and zones/boots up considerably faster. Also try fps limiting on background windows. I haven't gotten it to work but I heard it improves performance. You can do this in the SoD or UF client advanced options or in wineq2(I think you need premium).