Impossible RAM Timings?

[williamho]

Hi community,

Long time lurker, first time poster here. My friend recently showed me his new rig (i5-4690k, Asus Z97-K, Corsair Vengeance 2x8GB DDR3 1600), and the memory timings really stood out to me. He was running his RAM at 11-12-12-12 timings at 2133 MHz, which is strange because IIRC, the RAS value should be around 3xCAS.

Is my understanding of RAM timings flawed, or is there something different about Corsair's DDR3 that I don't know about? Thanks!

 

[Tradesman1]

Should prob be 11-12-12-32 or so, prob read wrong or app read it wrong, the timings are on the slow side for 2133 sticks - might want to check them for the optimal values

 

[williamho]

Should prob be 11-12-12-32 or so, prob read wrong or app read it wrong, the timings are on the slow side for 2133 sticks - might want to check them for the optimal values

That's what I thought too. But I'm not so sure after quickly playing around in the BIOS, since the reported timings at XMP defaults are 9-9-9-24 at 1600MHz and the computer works all the way down to 11-12-12-12 at 2133MHz but won't POST at 11-12-12-11. Maybe he got lucky? *shrug*

One follow-up question: How much of an advantage will a RAS of 12 have vs. 24 or 27, and what should be the highest priority when overclocking RAM?

 

[Tradesman1]

If it's showing a tRAS of 12 somethings wrong - what does it show in CPU-Z in the memory tab