because 300MHz is what it runs in 2D, your card is clocked fine, since 3dmark checks the speeds when it boots up, which is still in 2D, that's what it sees. There's no problem, you did it fine.
Thanks a bunch. Thats what I figured. For reference, I posted a 4774 in 3dmark03 with the 5900 bios, with an athlon xp 2400+ and a gig of ram. Didn't shut down any software.
After the flash, and letting the clock stuff autodetect overclocked settings, it scored a 5521. Not bad for a free upgrade!