Although GDDR5 allows for faster memory bandwidth, it doesn't necessarily equate to more performance. If you stick GDDR5 memory on a 7600GT (not saying you can, but just as an example), it is not going to outperform a 8800GTX, which uses GDDR3.Comparing the same card, however, GDDR5 will give you a bit of a performance boost. Especially for $15, I would say that it is worth it.I hope this helps!