Here is my 2C. I'm sure it's not much, but just shows that memory does help - at least in synthetics.

According to Legit Reviews, the HD4870 gets P8769 3dmarks.
Their processor is the newer Q9770.

My system, with the card clocked at 720/1050 and my q6600 at 3.6ghz I get P7850 marks.

The net processor performance, I am guessing is the same since, although theirs is 3.2ghz only, it's the newer version with higher performance/clock. Also, I do not think the CPU score has a very large impact on the overall score.

Seeing as how my clocks are so close to the 4870 (with the memory overclocked, even) and my score is so far away, I am guessing that the GDDR5 does have an impact, but it is not that large. I am sure that if I pushed my core to 750 I would jump my score to P8100.


Just my 2C