I'm on a 6-year old BTX based machine. I have an Intel SSD in it...and TRIM works just fine.
Trust me...it's not an issue.
SSDs work with motherboard chipsets as old as the Intel 8xx series - to put that in perspective, those were new when Windows XP was the OS du jour among Neowinians.
The issue is the controller chipset - TRIM support helps, but is not a requirement, any more than AHCI is. ICH5R supports AHCI; however, ICH7 does not. (The ICH5R southbridge was the preferred southbridge for the 865PE and 875P chipsets, while ICH7 was the default for both G31, AKA Bear Lake, and G41, AKA Eagle Lake.) However, ICH7, despite the lack of AHCI, does support TRIM in the default driver for Windows 7/8, as do *all* Intel southbridges back to even the original ICH5 - whether the southbridge supports AHCI or not.
Having both helps - however, neither is required, and one can exist without the other.