Then I'll get a 6670 DDR5. I'm planning to get a new PC at a later stage, and might try AMD for the first time, the A10 - 5800K. I think it has an integrated 7770, so when I buy a new PC, can I add the 6670 from the old PC so that both the integrated and the discrete card are used?
Can bottlenecking damage the graphics card?
No,bottlenecking will cause no damage whatsoever-it will only have an adverse effect on your system's performance while running graphically intense games and other resource hungry apps.
For instance,i had a geforce 450 gpu on my older system,that also consisted of a Pentium D 2.66 GHz cpu and 2 GB ram.Although my gpu was quite powerful,i could not run most of the newer games such as Need for Speed:the run,LA Noire,Ghost recon future soldier etc.Whenever i tried running any of these games,i experienced a high degree of stuttering and lag,which made them unplayable.However,when i upgraded to a better CPU( core I5),i could play all the games at high settings even though I was still using the same old GPU(i.e. geforce 450),which clearly proves that it was being bottle-necked by my older Pentium D CPU.
Btw,what are the games that aren't working on your current system?