I don't know. You'll need to go to your motherboard vendor's website and check the RAM compatibility table for your motherboard and see if the setup you have is listed as compatible. It doesn't have to be exactly the same model, but if a similar model works with the same configuration (same amount of RAM, slots used, etc.) then there's a good possibility that what you have should be good for your mobo.
The think I just don't understand though is how that stick evaded Memtest. If you wish you can try testing just that solitary stick with Memtest overnight to really pressure it. Otherwise I'm pretty baffled, especially since Prime95 on Large FFT tests very little RAM and is almost solely CPU.