Originally Posted by newls1
Hello forum users, i've got a quick question i need assistance with please. I'm using a Asus X99A-II motherboard (also Asrock X99X Killer 3.1 has same issue) and have spent so many hours trying to understand why OC'ing 8gb x4 (32gb set) of ram is so difficult. The ram im using is a 32gb set of 4 sticks ADATA 2800 DDR4. Also have tried a few sets of Gskill 32gb sets all with about equal results and im guessing regardless of which manufacture of ram ive used, i **THINK** the ram IC's were all the same as to why my OCing ventures were all similiar redface.gif .... My question is this: In the bios of either board there is an option called "BCLK FREQUENCY : DRAM FREQUENCY RATIO" If i set that to 100:100 all ram speeds work up to 2400 speeds, anything i apply faster then 2400 using 100:100 setting will not boot. IF i change that setting too 100:133 then ram speeds work up to 2700, then its like i hit a brick wall and even my 2800 speed ram will not POST. Why do i need to have a 133 divider to have ram work, I always thought it was better to have everything equal... meaning 100 : 100??? Also, before someone says im adjusting a cpu strap I AM NOT.... this is not changing multi on cpu... this is dram speeds only. Also, i have adjusted my SA voltage to no avail, and played with most things to get ram speed up to 3000, unless you know a secret, I cant get machine to post with anything above 2700 worriedsmiley.gif . Appreciate any feedback on this 100 : 133 divider question
1st...don't you know what the enter key is
reading one long line like that is a pita trying to see pertinent info....
In my experience same board as you with a 5820k I have found RAM will not OC above 2666mhz on the 100 strap , switch XMP on , which sets 125 strap for me and ram is happy at 3000 at 1.35v (per Corsair Specs for my Vengeance 32GB kit) , no need to play with SA etc either, Auto handles it, only need to do that if you also OC the CPU , but Auto is pretty good to start anyway (bit high usually).
Actually I am on my 6th X99 MB and all have acted the same with a 5820K but YMMV ? Had Gskill 2800 mem 1st but RMA'd it)
leave the BCLK/Dram Freq.Ratio on Auto.... set the DRAM Speed only, if setting XMP hasn't done it for you.
Don't forget to change CPU /cache ratios etc to something safe if going to 125 strap , if not done auto by XMP too.