Question Memory speed wont change after enabling DOCP

[tygzy]

My relevant specs are:

CPU: Ryzen 7 5800x
MoBo: Asus B550 Plus
RAM: Corsair Vengeance 4x16gb 3600Mhz

So I originally had 2 sticks of 16gb totaling 32gb, which I had enabled DOCP and had them running at 3600Mhz. I just got another 2 sticks of the exact same memory to complete my original goal of having 64gb, and so I installed them, reset my CMOS and then entered the bios, and enabled DOCP and now it won't make the memory go up to the full 3600Mhz, instead, the new set are running at 2666Mhz and the original set are running at 2133Mhz.

DIMM slots:

A1: new stick
A2: old stick
B1: new stick
B2: old stick

Unless I'm misinformed this is the correct order to put them in so I don't think its an issue of the order, whether it would even be an issue since all of the sticks are the exact same.

 

[Karadjgne]

I just got another 2 sticks of the exact same memory

No. You did not. You bought 2 sticks of the exact same heatsink and specs, but the ram itself is entirely different.

Think of it like pizza. You can go to the store and buy every box of pepperoni pizza of the exact same brand, box, size, shape etc, all seemingly identical. Open all the boxes and there's not a single pizza that looks identical, the cheese is spread differently, the pepperoni is spaced differently etc. That's ram. It only looks identical on the outside, even if the specs are identical, the silicon is not.

What you have is 2 kits. There's no guarantee that they are fully compatible or will work well together. The only guarantee is that the individual kits are made up of ram that's factory tested to work within the kit at rated specs.

There's only 3 possibilities with ram. It works as intended, it works as intended with tinkering or it does not work as intended. You have 2 kits currently not working as intended. Tinkering may change that or may not.

 

[tygzy]

No. You did not. You bought 2 sticks of the exact same heatsink and specs, but the ram itself is entirely different.

Think of it like pizza. You can go to the store and buy every box of pepperoni pizza of the exact same brand, box, size, shape etc, all seemingly identical. Open all the boxes and there's not a single pizza that looks identical, the cheese is spread differently, the pepperoni is spaced differently etc. That's ram. It only looks identical on the outside, even if the specs are identical, the silicon is not.

What you have is 2 kits. There's no guarantee that they are fully compatible or will work well together. The only guarantee is that the individual kits are made up of ram that's factory tested to work within the kit at rated specs.

There's only 3 possibilities with ram. It works as intended, it works as intended with tinkering or it does not work as intended. You have 2 kits currently not working as intended. Tinkering may change that or may not.

Okay I'm perfectly aware that everything is obviously not the exact same, I just meant its the same specifications for all 4 sticks, i'm not exactly sure how this is relevant. But you mentioned there being no guarantee they will work together but I don't think this is an issue because I could get the older set to get to 3600Mhz on it's own, but now I can't get it to go up to the full speed even seemingly just because its paired with the other 2 sets

 

[Karadjgne]

Right.
Regardless of the heatsink, all ram in each DDR family is essentially the same design, bunch of silicon chips soldered to a pcb. The factory bins the ram and sets the stats according to what the ram will take then tests for compatibility with other sticks to make the kit.

Each chiplet is cut from a sheet of silicon, but the silicon is not pure, only mostly so, depending on the quality of manufacture. So chances are extremely good that any chiplets from the same batch are going to be compatible. That's when you'll get 4x sticks in a kit, 3 sequential and 1 slightly off etc. But. The next batch is a different sheet, different levels of impurities.

So your original kit could be made from 99% silicon, 1% iron. The new kit you bought that looks to be identical could be 98% silicon, 1% lead and 1% aluminium. So each individual kit will function as rated, but that does not mean that just because the stats and heatsink are identical, that the aluminium kit is compatible with the iron kit, once DOCP is enabled. You are seeing only the 5 Primary timings of each kit, you aren't seeing the 40+ Secondary and Tertiary timings which could easily have wildly different numbers, some of which can't be lowered or raised to match the other ram requirements for stability at a given speed.

You can try bumping SoC to 1.2v, raising the ram voltage to 1.38v, other than that you'll need to be digging into the Secondary and Tertiary timings to try and find numbers that work for both.

 

[kerberos_20]

MoBo: Asus B550 Plus
RAM: Corsair Vengeance 4x16gb 3600Mhz

asus has two b550 plus mainboards, either prime or tuf, which one is it?
for ram, corsair differentiates them with version number, if that number is different, then sticks arent same (different IC, different PCB, different SPD, different amount of IC)
anyway both asus b550 plus boards can work with four single sided ram modules at 3600MHz (4x8GB), with dual sided sticks QVL has only few ram modules available and whats odd is theres no samsung, just hynix/micron at CL17-19
anyway since XMP doesnt work for you and obiously you dont know how to overclock ram, then you could return/sell your current RAM and buy matched pair of 2x32GB (preffered) or 4x16GB (from asus QVL)

side note: official ryzen 5000 ram support (without overclocking)