Grabbed this from Drunkenmaster on OCUK. Some pretty interesting tidbits.
Some food for thought which I posted in the memory thread.
First off we had some rumours about weak IMC due to supposedly low speed. This was followed by a rumour that actually Zen had insane efficiency way above Intel and as such lower speeds actually had same performance as higher on Intel.
http://ranker.sisoftware.net/show_r....1b7c4f9c9&l=en
This is a Zen getting 33.99GB/s out of 2133Mhz memory, which has a theoretical maximum bandwidth of 34.128GB/s... meaning, epic efficiency.
For comparison you have
http://ranker.sisoftware.net/show_r....5b3c0fdcd&l=en
Broadwell-e with 3200Mhz memory achieving 74.97GB/s with max theoretical of 102.4GB/s, so around 75% efficiency.
http://ranker.sisoftware.net/show_r....4b2c1fccc&l=en
Skylake with similar (lower latency though) memory achieving 26.52GB/s at 2133Mhz, with obviously max theoretical of 34.128GB/s. A little over 75% efficiency. Another way to look at the results, if true, is that Zen has 28% higher bandwidth at the same memory speed.
If that scales at the same rate then 2666Mhz on Zen would give the same bandwidth that Skylake(and thus Kaby) would at 3400Mhz.
Along with those rumours was a mention that Zen was currently locked at 1t, we also have Asus managing to get higher memory speed. I wonder if Asus unlocked some settings that aren't supposed to be unlocked yet and in doing so managed to lower timings to up memory speeds, but sacrificing efficiency.
Basically I'm just trying to say, heads up, new platform, don't assume 2666Mhz is even bad, OR that 3200Mhz(at potentially much lower timings) is automatically better than 2666Mhz.
http://www.corsair.com/en-eu/blog/20...ddr4_synthetic
Posted this before, but another thing to bear in mind, Haswell tanked in bandwidth efficiency after 2400mhz. We absolutely do not know that super fast memory speeds will bring ANY better performance yet. I mean Sisoft doesn't usually get faked afaik, and the result fits with some rumour 1-2 weeks back, it would also explain most issues of getting higher memory speeds.