So I currently have a nearly 4 year old 4870 1gb that I use in my system. I have been thinking about getting a new card but am not sure as to whether I will see a marked improvement in performance. The 4870 is OC'd to 850mhz core and 1050mhz for the memory. Its runs stable and never exceeds 60*. I see that some of the current 6970's have a clock speed anywhere from 800-850mhz for the core and the memory is slightly higher at about 1200-1300mhz. With these specs being so similar to my current card, is it really going to make that much of a difference if they were both 1 gb?
More aboutcard question
Note that you can't judge cards by memory size (video memory (VRAM) size) or clocks.
Also the 6970's has got 2GB .
Now instead of looking at the VRAM or the clocks, we look at the GPU, which is the 6970, and will be much faster than 4870.
You can only compare clock speed/memory when talking about the same models or at least the same generations of cards. The 6xxx series is two generations newer than the 4xxx series and uses a much newer architecture. As you can see from the benchmarks the 6970 is two and in some cases three times as powerful as the older 4870.