okies
um... reading through your stuff... I think it is redundant drivers conflicting possibly...
but you may also just have gotten a bad card
the line problem you are describing could be corruption due to various reasons.. such as vsync... dunno if fast writes are going to affect the card...
something I regularly suggest
is to place the card in another system and see how it performs... IF it is working fine in anohter system we can take one thing @ a time with your setup because we will have eliminated one problem
concerning the redundant drivers... I would HIGHLY recommend completely removing all registry calls to the nvidia drivers you had... I am sure someone here can give you links to a registry cleaner that will do just that... also uninstall all your ati software...
once you have cleaned both... install a fresh set of cat 3.0a drivers with dx9
and voila... if the card is NOT the problem (read previous paragraphs) then this will aid you somewhat...
for benchmarking... look in your video cards control panel and see how high your AA and FSAA is set... by default there is a certain amount turned on... this gives better visual details but lower performance... check those settings as well... most people bench @ performance with no aa and fsaa enabled
things would be easier to solve if you formatted but I understand why you are not
and we will try and help you work around that..
g.luck