RAM change = Performance loss?

Comp specs before:
-------------------------
AMD Athlon 2000XP
Epox 8rda+
2 x 256MB PC2700 Crucial RAM
40GB HD 7200RPM
Geforce 3 @ 210:490

3dmark 2001 score: 9700


Comp specs after:
-------------------------
AMD Athlon 2000XP
Epox 8rda+
1 x 512MB PC2700 Kingston HyperX RAM
40GB HD 7200RPM
Geforce 3 @ 230:520

3dmark 2001 score: 9000

As you can see, all i changed was my RAM, from 2 stick of 256 to one stick of 512. Whats also apparent is that my 3dmark score dropped a good 700 points -- although all my RAM settings, multipliers, etc are all the same, i even oc/ed my video card more!

what could be causing my horrendous drop in performance?
what could it be?

Were you running dual channel before? Are you running the same memory timings that you were before? Different timings could definatly cause a very large change in 3dmark scores.

i was running dual channel before, the ram timings are all the same.

could dual channel account for 700 3dmarks?

yes.

hmm.. that sucks, any tweaks i could try to get some more performance outta my system?