alidan,
There is NOTHING in the specifications of DDR4 that makes it faster than DDR3 if both are running at same frequency.
ANY *real* increase in performance when both using *same* clock freqencies must be attributed to CPU or Chipset differences.
Only real advantage of DDR4 is power drain...that's *ALL*.
However, even that gap could be minimized if DDR3 manufacturers reduced the voltage of DDR3 (witch they are doing) and in special if they used the DDR3L,etc. specifications.
All this is/was possible, it's only a question of WILL from them.
Why do you think DDR4 was all this time in "development" ? Because there was no perceived reason to do so....and the numbers in this test shows that the increases of frequency, even going from 2133 to 3000mhz don't reflect in increase of performance.
*IF* there is no increase of performance going from 2133 to 3000, *why* dump DDR3 that can achieve same performance at lower price ?
Only reason would be power drain but even that could be minimized via more DDR3 standard compliant voltages, DDR3L,etc. or undervoltage.
There must a LOT of performance increase in DDR4, in special timings but also even greater frequencies AND CPUs/APUs that really can use that RAM performance, to it be really a significant improvement in games,etc.
Even in APUs (from AMd or Intel no matter Intel APUs are not called that way) DDR4 brings VERY LITTLE , near ZERO improvements.
MUCH more radical improvements would be large amounts of RAM in the SoC to work as a RAM video (but that would be too expensive) or color compression new techniques that start to happear already in NVIDIA and AMD most recent cards.
Any of those options would increase the graphics bandwidth of the APUs to a much higher level than any DDR4 , even at 4000MHz, could do...and at a fraction of the cost in the case of color compression.
AFAIC, for *now* is a complete WASTE of money to make an upgrade because of significant costs (RAM plus CPU plus MoBo) for reduced, or even i dare to say, insignificant improvements in performance.