AB350M - 4 pieces of RAM and dual channel question

Strange, the 'pure' AB350M has only 2 UDIMM slots. I suspect you didn't put the entire model name of your mobo.

Other AB350M mobos from ASRock, which have 4 UDIMM slots are only guaranteed to run 2133MHz with SR RAM in all 4 slots, and 1866MHz with DR RAM (again in all 4 slots).

With a bit of luck you should be able to run original speeds, but keep in mind Ryzens currently are still lacking in good memory support.

With all that being said, if you have cash to burn, get them and try. Or better, sell the old ones and get higher speed, higher capacity sticks (just 2). Check my sig for what I recommend as a fast RAM for Ryzen.

My bad here as well. I didn't elaborate enough as well.

4 sticks of RAM will run in dual-channel! Sometimes, when you try to dial some high RAM speeds, CPU won't be able to 'train' the RAM for that speed, and will revert to single-channel as a result.

As I wrote in my previous post, 4 slots of RAM are only guaranteed to run in dual-channel if you're running @ 2133 (single-rank, nothing to do with single-channel), or 1866 (dual-rank, nothing to do with dual-channel).

Macready wrote: zlobster wrote: My bad here as well. I didn't elaborate enough as well. 4 sticks of RAM will run in dual-channel! Sometimes, when you try to dial some high RAM speeds, CPU won't be able to 'train' the RAM for that speed, and will revert to single-channel as a result. As I wrote in my previous post, 4 slots of RAM are only guaranteed to run in dual-channel if you're running @ 2133 (single-rank, nothing to do with single-channel), or 1866 (dual-rank, nothing to do with dual-channel). OMG, so you're basically saying that if I add another two 2666MHz sticks to my current ones, ALL FOUR 2660Mhz memory sticks will be downscaled to 2133Mhz?

Aye, comrade! Just a small clarification, that's what the specifications are saying. I'm just reading the mobo manual out loud for you.

That's an inherit limitation of AMD's current state of AGESA. It's commonly believed it will be improved in near future.

To make things even more 'enjoyable' for you, I have something else to tell you - my Googling shows that your RAM is most likely a double-ranked. Basically, it means 1866 for you if you decide to go for 4 sticks.

With all of the above said, it's not all that grim! 4-DIMM speeds not being guaranteed doesn't automatically mean impossible! Currently it's a matter of luck. 2666 is not that high, so with a good RAM there is a good chance you'd get there. Just not with a double-ranked one, like yours.

Personal advice, cough some more cash on the pile and get a decent, high-speed 2x kit. There is absolutely NO benefit if you go for 4 sticks vs 2 sticks. 2 or 4, it's all dual-channel. It makes sense only with Threadripper and other high-end Intel platforms.

Macready wrote: Unbelievable. I have assembled this PC only two weeks ago and I'm already starting to regret this...I should have stick to Intel  I guess I will have to sell this 2x4gb Corsair memory (I've just bought it...) and buy 2x8GB one...any suggestions what kind of memory (brand/mhz) should I buy? I guess something that would be compatible with AB350M Pro4...ehh

Sticking to Intel? Good one there, mate! Let me fast-forward to today for you:

http://www.tomshardware.com/news/intel-spectre-bios-crash-broadwell-haswell,36324.html

http://www.tomshardware.com/news/intel-amt-bitlocker-bios-bypass,36321.html

http://www.tomshardware.com/news/intel-releases-meltdown-spectre-patch-benchmarks,36317.html

Please read those carefully and see if you have changed your mind.

As for the memory, you could check here: https://www.asrock.com/mb/AMD/AB350M%20Pro4/index.asp#Memory

That's the official QVL for memory for your mobo. Depending on your budget and regional availability my suggestions may not be that viable. I'd generally go for G.Skill, but theoretically everything from the QVL should work fine.

If in doubt, drop us a line again. Maybe other guys here can share their personal experience with RAM and same mobo as yours.

I am able to run 4x8 (32GB) Corsair RAM (Micron die) @2933 and it's rock solid.