G100 gddr2 vs Radeon 6670 gddr3

Hello there,

My brothers computer is running a G100 gpu, now I read that a G100=9600gt=8800gt since they are rebrands of the same card. However I also read somewhere that the g100 is more on par with an 8400gs, so I'm not sure what to believe.

Anyway I was thinking of upgrading his card so he can run minecraft at a higher fps, and my searches turned up the best card in this price range is the Radeon HD 6670. The price range is 50-70, being in Canada, everything costs that much more than in the U.S.

Anyway the best priced 6670 I can find available to Canada is the Gigabyte Radeon HD GDDR3, which comes out to being 65$. The thing is, I'm wondering if this would be a significant improvement, there is little information on the gddr3 version of the 6670, and even less info on the g100. So I'm not sure.

I understand that the GDDR3 version will be significantly slower than its GDDR5 counterpart, but we cannot afford that model or anything more. And I understand that this is a budget card we're talking about, someone might suggest we spend 100$+ and get a real card, but we're not willing to.

So question is, is the 6670GDDR3 going to be any faster, or will it be more of a step sideways? If it's only slightly faster we won't bother getting it and we'll just have to wait for prices to fall.