Possibly bad RAM, any hope of not having to do an RMA?

I got two sticks of 4GB G Skill Ripjaws X DDR3 1333 yesterday to add on to my current set of the same RAM. The memory worked great from the start, and I didn't notice any additional stability problems. Rebooting this morning, however, sent my motherboard in to a boot loop at BIOS code 55 (early memory initialization). Removing, rebooting, and then replacing the RAM (while the system was off, of course) allowed it to reboot again with the RAM, and I again noticed no stability issues. I didn't have time to run Memtest86 on the memory before I had to run to work, and I didn't feel like running the computer unattended with a potentially bad part, so I put it off until I got home tonight... at which point the motherboard kept rebooting on code 55, and my previous trick did not work at all. I'm thinking the memory is probably bad and I'm ready to do an RMA, but I'd hate to go through all that if it's just something stupid.

System specs:

Motherboard: MSI Z77a GD80

Processor: Intel i5 3570k OC'd at 4.2GHz

Memory: 4x4GB G.SKILL Ripjaws X Series 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL9D-8GBXL

Video Card: BFG Tech Geforce 8800 GTS 320mb OC

PSU: KingWin Lazer Gold Series 850W ATX Power Supply (80Plus Gold Certified)

Can provide additional specs if needed, but those are the only parts that I can think of that could potentially mean anything for a failure to POST like this; I also have fairly little running off the PSU at the moment so I'd imagine it's under 50% capacity at the moment. And, although the processor is overclocked, RAM is running at stock speed.