You sound like you are running with 2GB in a 4x512 config. There is a K N O W N issue with DDR400 timing with a 4x512 config on the Asus board. It isn't a bug. Rather, it has to do with the memory controller. I am sure that if you ran in 2x512, you'd find that you (should) get your DDR400 timings.
A couple of your problems seem to be that you believe everything that is said (e.g. Newegg reviews), and you didn't seem to consult the memory tables for your motherboard on the Asus website (part of RTFM for the mobo). You have to learn that you have to understand the nuts and bolts a bit more before purchasing. I also echo what pyrix and tcdude said...
If you are using 4x512 you are guaranteed ONLY DDR333 (in most cases) if you don't run specifrically what Asus recommends. Since there have been so many discussion on the 4x512 issue, I elected to stay away from that configuration myself.
So, do yourself a favor - RTFM (at least on the website - and don't forget to check the memory table), do a Google or two and buy some GOOD memory. I am using 2x1GB OCZ Platinum at DDR400 (with the same core), and haven't noticed a hiccup. Granted, the memory will cost you - but - you do get what you pay for.