Problem with framerate.

[I)eadnerzhul]

Hey guys. Recently, I reloaded my computer with Windows 7 Ultimate 64 bit. Now, my dad got me a new and more powerful graphics card, the ATI Sapphire 4850, but instead of working better than my previous one, it is worse. I tested a game that I've played prior to reloading my computer and changing my graphics card, and every so often, the framerate gets really choppy. I checked the device manager, and Windows 7 said that the drivers were up-to-date, so I'm not sure what the problem is. Any suggestions?

 

[DarkAngelAzazel]

Hmm what system did you use before?
A 32 bit system maybe?

 

[Element of Water]

every so often

Does this seem to be random, or when the graphics seem particularly intensive?