Did you blow out the video card heat sink?
Also, do you have the games video settings at their lowest setting?
That video card (the NVIDIA geforce gt 520) is a
low end card. It should perform similar to the following cards: 6600 GT, 6800LE, 6800 XT, 7300 GT (DDR2), 8500 GT, 9800 XT, X700 PRO, X800 GT, (which are all in a similar class of performance).
The above listed cards (and the NVIDIA geforce gt 520) should be able to run DAoC somewhat ok on the lower video settings for all of the games PvE and also in most of the BGs. If you get into larger zergs in the Frontiers then you will be looking at a slide show. Also, there are some areas of the game that just have rendering challenges.
In general and in many areas of the game your card should render the game well enough on the lower settings so that you do not have a constant red indicator for frame rates on the performance meter.
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The art of war is simple enough. Find out where your enemy is.
Get at him as soon as you can. Strike him as hard as you can,
and keep moving. - Ulysses S. Grant
Only the dead have seen the end of war - Plato