How do you run 2 memtests at same time

Trying to run Memtest on my new Opteron system with 2 gb OCZ gold PC4000. Its says it can't run a test on that much ram , but to run 2 memtest each allocating 869mb of memory. I've tried everything I can but can't get it to run 2 at once.
I've ordered the deluxe version from the website and I'll have it in a few days, BUT it may not supports AMD64 cpu's yet.

Anyone know of another program to test memory on an opteron system with 2gb onboard?

Just use Memtest86+ on a bootable ISO.