Question Speed drop when populating all four RAM slots

[lifeblood]

I have an Asrock AB350 Pro 4 motherboard (System in sig below). It has 8GB of RAM (2x4GB of G.SKILL Ripjaws V Series). The memory is clocked at 3200MHz and runs perfectly stable. I want to take that up to 16Gb by buying another set of the same RAM giving me 4x4GB. I've heard that if I populate all four RAM slots the motherboard will not be able to keep it at 3200MHz but will slow down to something else. Does anyone know anything about this? Any one with this motherboard running all four RAM slots populated at 3200MHz?

 

[LTC8K6]

https://www.asrock.com/mb/AMD/AB350 Pro4/#Specification

Scroll down for the mem speed charts.

But I can't find anything specific about filling all 4 slots and losing speed?

 

[LTC8K6]

https://www.asrock.com/mb/AMD/AB350 Pro4/#Memory

That seems to show that higher speeds are only supported with 2 slots?

 

[VirtualLarry]

It happened to me, with the AB350M Pro4 (note the "M" - micro-ATX).

I had 2x8GB DDR4-3000 Team Vulcan, which ran at 2933 with an R5 1600. Then I doubled-up, with two kits, and it wouldn't POST at anything over 2400.

 

[lifeblood]

It happened to me, with the AB350M Pro4 (note the "M" - micro-ATX).

I had 2x8GB DDR4-3000 Team Vulcan, which ran at 2933 with an R5 1600. Then I doubled-up, with two kits, and it wouldn't POST at anything over 2400.

That's not what you're supposed to say. You're supposed to say "No, I did it and it worked fine."

Damn, now I have to find out how much RAM i'm actually using and if it's near 8GB I'll need to buy a 2x8GB kit. I really don't want to wait for the HD to swap to disk when I have a bunch of bad guys attacking me in my game.

Was that with an older BIOS maybe?

[Edit for spelling/grammar]

 

[UsandThem]

It's pretty common for Ryzen CPUs (since the memory controller is on the CPU) to reduce the speed when all four slots are occupied. There are not many modules that will run at their full speed with all four slots occupied.

Unless you want to pay a premium for those few modules that can do that, your best bet is to sell what you have, and buy a 2 x 8 GB kit that is on your motherboard's QVL list (or memory manufacturer's QVL list) that can run at the faster speed on your board.

 

[kurosaki]

Is the Ryzen really scaling that good? If you just game, I don't think the reduction in speed would be an issue

 

[UsandThem]

Is the Ryzen really scaling that good? If you just game, I don't think the reduction in speed would be an issue

https://www.anandtech.com/show/11857/memory-scaling-on-ryzen-7-with-team-groups-night-hawk-rgb/7

On the benchmarks where it matters, our memory kit was above to push performance up and over 20%, although despite the few benchmarks where this happened, it was outnumbered by benchmarks that had zero or a very minor effect. Some gaming titles had up to a 5-10% difference in average frame rates, but others had zero change

Yes, there is a noticeable difference with slower RAM.

 

[kurosaki]

A shame they strapped all memories to cl16. 2400mhz ram could easily be found in cl14. Wonder what kind of impact that would make.

 

[dlerious]

That's not what you're supposed to say. You're supposed to say "No, I did it and it worked fine."

Damn, now I have to find out how much RAM i'm actually using and if it's near 8GB I'll need to buy a 2x8GB kit. I really don't want to wait for the HD to swap to disk when I have a bunch of bad guys attacking me in my game.

Was that with an older BIOS maybe?

[Edit for spelling/grammar]

You can get a decent sized SATA SSD for less than $100 (NvMe like WD Black about $130) for 500GB. Even SATA is a big improvement over spinning drives.

 

[PingSpike]

It's pretty common for Ryzen CPUs (since the memory controller is on the CPU) to reduce the speed when all four slots are occupied.

This has been pretty common since the IMC was introduced actually. I remember DDR speed support had different specs for 2 vs 4 sticks on A64.

Also, do you guys remember mixed size dual channel support? I actually bought a 8GB stick to go with a 2x4GB kit on my ivybridge system a few years ago just assuming I could run the 3 sticks in dual channel like I'd done on past platforms only to find out you can't do that anymore! I was pissed!

 

[kurosaki]

Hos would you run 4 X 2 +1 x8 in dual channel? Seems like witch magic to me!

 

[LTC8K6]

Hos would you run 4 X 2 +1 x8 in dual channel? Seems like witch magic to me!

Intel Flex memory mode allowed mismatched memory to run in dual channel mode up to the amount of memory that matched, and single channel for the rest, and as far as I know, still does allow you to mismatch ram.

A 4gb stick and 8 gb stick would run in DC for the first 8gb, then in SC for the remaining 4GB, seamlessly.

 

[kurosaki]

Wow! The more you know! How could I have missed that!