Modern gpu are highly parrallel (and predictive)
In practical case you ll always get better result with higher bandwidth than tighter timing in games. APU benchmark which only depend on the main PC memory, always showing the same story, bandwidth win, all the time even for cpu tasks (!))
All high end gpu use GDDR5, no one came up with a 500$ PC gpu stuffed with DDR3 bragging about how efficient it is cause of DDR3 latency. That whole thing is the worst "damage control" ever heard.







