Soldato
Just researched this, GDDR5 is a faster version of DD3, it probably has double the bandwidth and latency is actually the same. Xbox has a much larger on die cache than PS4, but it's smaller than I thought. The PS4 is more capable than the Xbox.
I saw something a few weeks back saying that GDDR5 will be a benefit to graphics but DDR3 will benefit the CPU.
Something to do with DDR3 moving chunks faster, but smaller. And DDR5 moving larger chunks slower.
Not sure how that translates to the different architectures. But there is a benefit to the DDR3.