Windows 7 issue?

hello all. i have a nice PC setup and have been running ddo with windows xp for a long time, and never really had a huge lag issue, just the normal. anyhow after the wife kicked a breaker in the house shutting my pc off while in game 2 times in a row it crashed my windows xp grrr lol. anyhow after that i contacted my buddy who offered my windows 7! when i installed it i installed ddo. now the game loads the same and everything. but the problem is when i get in a raid i get a huge lag spike every 5 seconds! and even worse, when im in the market place or harbor i have soooo much lag i want to smash my 32 inch pc screen. now i didnt have this huge lag spike when i had xp. so im 99% sure its windows 7. is there anything i can do to fix this? things ive noticed. yes i built this PC a couple of years ago:P but its still extremely good and ive played conan and warhammer on it fine (ddo rules! thats why im back) windows 7 has a monitor system that shows ram speed and cpu speed. ive noticed my ram almost maxed out! i dont understand it because its not like i have cheap ram....heck the ram was the most $$$ in my system! when i built this ssystem i clicked on the newest and best money could but like i always do. also my friend told me to take windows 7 off of normal and put it on preformance and i did but nothing changed. please help! thanks ruffy

MY PC:
mother board: asus M2N-E
CPU: AMD 5200
ram: corsair dominator pc 6400 ddr2 2 gig
video xfx xxx 7950

What settings are you playing on?

If you are getting lag every 5 seconds in certain areas, something you can do is uncheck Environment Stencil Shadows under advanced graphics.

Something to note is that Windows 7 requires a gig of ram itself to run smoothly if you have glass and everything turned on, whereas XP hardly used any. You can change the theme to Windows 7 Basic, and adjust the performance settings to lower the amount of ram used by windows itself.