Try running with just the 1 gig. PAE mode isn't suppose to kick in without 4 gig of memory.
I've only installed giga byte memory in solid one gig increments. Check with your motherboard manufacturer. I haven't installed any in two years, so specks could change, but at that time gigabyte memory was designed differently from the smaller stuff.
The gigabyte memory also has an ecc scrub setting in the bios to get rid of memory errors. 8 gig of memory in a system can take 6-10 minutes to boot with ecc scrubb activated. If your not familiar with it, you'd think that "it ain't bootin!'


