8GB Memory Woes

Trying to be clever (always a mistake) I bought a 8GB RAM stick (Corsair XMS3) which I thought I could add to my aging Gigbyte GA-H55N-USB3 Mini-ITX motherboard (supports upto 8GB it claims) and then, when the call to the great motherboard in the sky came, I could transfer it to a new Intel NUC, add another 8GB stick and double upto 16GB.

I initally forgot it (Gigabyte board) could only support 8GB and stuck it in with one of the existing 2GB sticks, which seemed to work well until memory usage went over 2GB and suddenly the system crashed (no errors), presumably the memory wasn't really available or some timing issue stopped it working. Removing the 2GB stick though (so down just to 8GB, which should in theory be fine) has just lead to it getting stuck in a boot cycle, not even able to get to the BIOS. I've tried to reduce some of the memory options to the minimum and stuck everything on Auto but still it isn't picked up. Possible (see this lengthly exchange: http://www.tomshardware.co.uk/forum/280564-30-h55n-usb3-doesnt-post-rebooting-gskill-ripjaws) it could be something to do with the CPU, perhaps something wrong with the memory controller on the i3.

Anyway, the best laid plans... So the 8GB stick will be in storage for the moment until I order the Intel NUC.