AMD Ryzen 9 5950X and Ryzen 9 5900X

[DanceswithUnix]

This video might help....

https://www.youtube.com/watch?v=AGux0pANft0

He seemed to explain that quite well, I specially liked his graphs showing the 2070 super being too slow to show any benefit of quad memory sticks. That is not a slow card, and we don't all have a 3090 and can be happy with our dual sticks.

Edit: Would in interesting to know if my long compile jobs were helped, not every CPU load is gaming.

[CAT-THE-FIFTH]

Its quite interesting that some reviewers have forgotten Zen2 also showed similar behaviour WRT to RAM too!

[DanceswithUnix]

Its quite interesting that some reviewers have forgotten Zen2 also showed similar behaviour WRT to RAM too!

I thought it was quite well documented for zen2, perhaps they forgot or just never noticed.

I guess on the older zen(+) platforms having 4 sticks limit you to probably 2666MHz was more important than the extra open pages.


One thing in that video that grated on me was describing a system with 2 sticks as single rank. The sticks can be addressed independently so each stick might be single rank (it might not) you are actually looking at two ranks of ram. More importantly if each stick has 16 banks where each bank can have an open page, then with 2 sticks that is 32 open pages for the memory controller to play with. Stray off the open page within a bank and you have to close that page to open a new one giving a penalty.
With quad core systems having 32 open pages to play with seems plenty, but with these high end CPUs hitting 32 threads (or just some games hitting large amounts of memory seemingly at random) doubling the open pages sounds like quite a win.

Note that I don't design memory controllers, just have talked to people who deal with ram interfaces a lot. The precise numbers may be off above, but I think they are about ballpark.