overclocking with lots of ram
 

in general, is it more difficult to overclock a CPU when there is a lot of ram in the system? for example, is it more difficult to overclock a CPU with 6 gigs of RAM compared to 24 gigs?

i am overclocking a 980x and am having issues keeping it stable above 4ghz with 24 gigs of RAM at 1600mhz.

Most OC WR are set with a single stick of RAM. Even if all sticks are matching you never know where the particular failing point of a single RAM chip lies, with several sticks you multiply the failing points. Also lots of RAM are kind of hard on the IMC, you might need to up the voltage.

Yes, running with all the banks populated is much harder than with half the banks populated. That's why older systems like AMD Phenoms, DDR2 and earlier Intel systems, etc. reduced your memory speed by 1 multiplier notch (e.g. 800MHz to 667MHz) when you were running 4 sticks of RAM. You might have better luck with 3x8GB sticks unless that is what you are already using.

You'll need more qpi voltage most likely. Took me a long time to finally get my 950 stable above 4ghz. I have to use 1.375v for vcore and qpi. Also have 900mv offset, which was the final piece of the puzzle for me.

It also depends what mobo you're using.
I had absolutely no issues getting my ivy to 4.6 stable (water)
on an asus MVE with 32gb of 1600

This is a bigger deal on some architectures than others but in general, yes, due to stress on the IMC.

so, what's IMC?

Integrated memory controller in your CPU.

To compare, my 920 is at 4.2 GHz at the moment, but to get it table the rams is running at 1200 MHz, (mem multi at 4) this is with 6 sticks of 2 GiB 1600 MHz CL9 for 12 GiB, it barely want to do 1600 at stock (2.66 GHz).

Then again, 1200 MHz in three channels = 1800 MHz in two channels (192 * 1200 / 8 = 28.8 GB = 128 *1800 / 8) the 920 only supports 1066 MHz memory, the 980x goes up to 1333 MHz i think, but everything over that is actually an overclock of the IMC

Since it appears you updated your system specs from when I checked earlier, running 6x4GB is most likely your issue. Going 3x8G could possibly help your overclock.

that makes a lot of sense. i have the ram set at 1600mhz and the overclock at 4.1ghz. now i know why i can't get it stable. i should take the ram down to 1333 and that should do the trick.

I believe it is VTT which is IMC-related voltage. That could help stability at 1600. Perhaps a bit more VDIMM too.