What exactly is the problem.
Technically speaking it should be at least the same since the supporting hardware is as good or better than the previous.
You may want to ensure your drivers are similarly set (BTW, did you clean out the old ones before putting the new card in?).
The X1950 actually supports some additional features not available on the X1300, not vice versa, and the RAMDACs and TMDS are of similar speed (with the X1950P having 2 dual-link DVI, not just 1 like most X1300) and should be close to similar quality (baring production issue for specifically your card).
So a little more information as to what's different (text sharpness, contrast, etc.) would be helpful.
Also while it is 'the same monitor' some info about that too would be helpful for what you're trying to do, but of course it won't affect the differences in the cards/settings without something else coming into play.