But your request is for VISTA.... which causes further confusion in this thread..... I'm curious if you made a mistake when you chose Vista as your OS or if you actually need a Vista driver or if you changed your mind and really want a XP driver?
Are you saying that Gigabyte (your motherboard manufacturer) doesn't provide this file (for the OS you want to use)? If Gigabyte and the chipset maker of your SATA controller both doesn't, it looks like you might have a difficult time finding a working driver. I'm assuming the hard disk controller is integrated on the mb. What is the actual hard disk controller on this mb? Is it Intel or some other chip maker? Gigabyte is the company who is responsible for providing support for their motherboards. Often, they work together in close relationships with other companies like Intel, SiS, etc. to work out OS driver needs. So if Gigabyte doesn't provide the needed support you're next option is the chip maker. Beyond those 2, you're chances of getting reliable support is not too great.
I'm assuming that "trim support" has something to do with performance of the hd controller or the SS hard disk. What kind of performance issue are you dealing with "without" the driver file you requested?