Question Why is my system crashing after installing new RAM ?

[Tony_186]

First I'm going to give you some details about my pc. I have a Ryzen 5 2400g on an ASUS a320m-k motherboard and previously had installed 1x G.skill aegis f4 3000 8gb and 1x Crucial 2133 8gb. I wanted to upgrade my RAM and since the previous Aegis stick worked decided to get a kit 32gb f4 3000 2x16gb.

Now my pc is crashing with multiple different configs(lowered the clock to 2666mhz, disabled DOCP(xmp)).

What would cause this and is there a fix ?

I am aware that on the official G.Skill site it states that this kit is only supported by Ryzen 3rd gen and up, but a stick of the same line worked just fine before.

Thanks!

 

[LinuxDevice]

You shouldn't mix RAM of different timings or sizes (not necessarily an issue in your case). As soon as this happens you must go to single channel mode (a huge performance drop over dual channel) and you would need to avoid using the XMP speeds. When you have two sticks of RAM shipped in a single package there is a finer match of timings than if you buy two separate sticks of RAM advertised as the same exact thing. The only time two or more sticks of RAM are actually guaranteed to have a close enough match to work at full speed and timings is when they ship in the same package. Thus this question: Were both of the two 16 GB sticks from a single package? It sounds like they might be, so this might not be a problem, although one would normally start with XMP off and then turn it on later when it appears to be working.

The other issue is that if your motherboard is old enough the BIOS might not support this much RAM. I don't know. I suggest looking up the available BIOS updates, and closely look at the docs regarding how much RAM and what clock speeds the updates work with. This is probably the best case scenario since a BIOS update would solve the problem.

 

[Tony_186]

You shouldn't mix RAM of different timings or sizes (not necessarily an issue in your case). As soon as this happens you must go to single channel mode (a huge performance drop over dual channel) and you would need to avoid using the XMP speeds. When you have two sticks of RAM shipped in a single package there is a finer match of timings than if you buy two separate sticks of RAM advertised as the same exact thing. The only time two or more sticks of RAM are actually guaranteed to have a close enough match to work at full speed and timings is when they ship in the same package. Thus this question: Were both of the two 16 GB sticks from a single package? It sounds like they might be, so this might not be a problem, although one would normally start with XMP off and then turn it on later when it appears to be working.

The other issue is that if your motherboard is old enough the BIOS might not support this much RAM. I don't know. I suggest looking up the available BIOS updates, and closely look at the docs regarding how much RAM and what clock speeds the updates work with. This is probably the best case scenario since a BIOS update would solve the problem.

As I said before the specific kit of F-3000C16D-32GISB(single package 2x16gb) isn't supported by Ryzen CPU's that are older than 3rd gen. But I had no issue with a 8gb stick of the same speed and timings before AND it was paired with a random 8gb stick I already had.
I had tried with xmp off first and turned it on later as it didn't work and some sites give this as a fix.
The motherboard supports 32gb of ram.
It supports up to 3200mhz speeds.

Now in BIOS(Tool/ASUS SPD information) it says the maximum bandwidth of each stick is 2133mhz. <- if this means anything?

 

[USAFRet]

But I had no issue with a 8gb stick of the same speed and timings before AND it was paired with a random 8gb stick I already had.

Sometimes it works, sometimes it fails.

 

[Tony_186]

Sometimes it works, sometimes it fails.

True. But I'd like to know if it can be fixed.

 

[Misgar]

Now my pc is crashing with multiple different configs(lowered the clock to 2666mhz, disabled DOCP(xmp)).

Am I correct in thinking the system is stable with the new RAM running at 2666MT/s with DOCP switched off, but crashes when you run the RAM at 3000MT/s? Perhaps it's only stable at JEDEC 2133 or 2400MT/s?

I had a similar experience when upgrading the RAM on a Ryzen 2600 system. It worked fine at JEDEC 2133MT/s but not at XMP 3000MT/s.

If you check the spec of the 2400G and my 2600 online, you'll find they're both rated for use at memory speeds up to DDR4-2933.
https://www.cpu-world.com/CPUs/Zen/AMD-Ryzen 5 2400G.html

My Ryzen 5 2600 turned out to be extremely fussy about running at DDR4-3000. To fix this problem I set the RAM speed to 3000MT/s in the BIOS, then dived into the manual settings and relaxed the CL/CAS timings by 2 clock cycles.

I can't remember the exact figures, but I probably changed the default CL=18 to CL=20. This made the system stable. I checked by running MemTest86 for several hours and it passed with zero errors.

You might get away with increasing CL by just one clock cycle, e.g. change from CL=16 to CL=17. You'll have to check the true CL timings in your RAM at 3000MT/s held in the SPD chip on each DIMM. Your CL might be anywhere between 15 and 20 at a guess. The actual value isn't critical, just increase it by 1 or 2 clock cycles on both DIMMs.

you must go to single channel mode (a huge performance drop over dual channel)

I've always thought there's not a huge difference between single and dual channel in many real world apps.

I prefer dual channel (or quad channel ECC in my Xeon server boards), but at a pinch I've run single channel when one of the IMC channels in a CPU has failed or a DIMM socket is faulty. It keeps the system running.

This web site mentions a 5 to 15% increase in speed for dual channel:-
https://www.easypc.io/ram/single-channel-vs-dual-channel-ram/

A test on this site gives 19% improvement:-
https://www.technewstoday.com/single-channel-vs-dual-channel-ram/

What you do get with dual channel is double the bandwidth, but not all apps benefit from it. It's a bit like swapping a car with a 100mph top speed for a super car with 200mph. How often do you (or your programs) use the extra speed (bandwidth)?