panhead said:From your specs, I assume you are running 4 x 512MB modules. From Xbits labs "When four memory modules are in use, the memory controller of the Athlon 64 can only support DDR400 SDRAM with the slower 2T timing. Moreover, if the four installed modules are two-sided, the speed of the memory subsystem will be dropped to DDR333 even with 2T timing." http://www.xbitlabs.com/articles/cpu/display/athlon64-3800_3.html
If you want to run 2GB of memory I would suggest you get 2 x 1GB memory modules.
Although you could just wait for hte new E0 stepping from AMD, they are upgrading the mem controller so it can handle 4dimms at ddr400, fyi.