That board actually supports PC3200,
GA-8I865GME-775 - GIGABYTE - Product - Motherboard - Specification
- Type: Dual Channel DDR 400 / 333 / 266 support
- Max capacity: 2 GB
- DIMM slots: 2
which means just about any PC3200 up to 2 GB will work. One thing after getting it is you will need to go into the bios and set it to run at the proper speed, as the current stick of PC2700 is only running at PC2100 speed.
Having a quick look at the manual this is what is has to say for memory speeds,
which says to me it is either on the wrong setting or the auto setting isn't detecting the memory correctly.
Which CPU is in it, a 533 MHz or 800 MHz FSB one?