It's a standard x86 with standard ram interface. You can google linux ram test and probably find apps to test with. I imagine you'll have to run them from within linux, though, not at boot time, as I'm not sure you have enough control over the bootloader. That just means that it might not accurately test all your ram if some has been allocated already.
there is an application called memtester in portage that is a userland program for testing memory. However, it cant test memory thats currently in use, so in most cases, you wont be testing more than 10-25% of available memory
Shut down almost everything you can (ie. go on a killfest) before running the memtest app. That way you'll free up as much ram as possible. Especially things like apache or xwindows.