UE4 stuttering and ram?

I can't think of anything off the top of my head, but you can get into all sorts of fuckery with games. And it's probably specific to that particular title. Anything interesting on PC Gaming Wiki for it?

I am guessing 4x16 are all dual rank modules. That is a worst case scenario for the memory controller in terms of load.

What are the specific motherboard and RAM modules? What timings are you using? (Automatic or manually set or overclocked?) It's not uncommon for populating all the slots to result in requiring timings that are more relaxed, but that's very slight. Only specific benchmarking or closely monitoring FPS or load times in a game would show any difference. It would not cause the game to have extreme performance problems like you experienced unless that game is absolutely maxing out the capabilities of your system already. If this is a sudden change to a game and system that has been working fine, then it's possible that a component on the motherboard, RAM or even the power supply has degraded so that the timings are too extreme.

However it's possible that your BIOS/UEFI settings are forcing the timings to go beyond what they should be with all four slots populated, rather than letting them run at what the board knows should be the limit. If you switch your settings to default/auto, does it make a difference? Very slightly tweaking voltage to the RAM could stabilize it at the timings that you want to use, and ought to be safe.

Memtest is a good test, but not infallible. Aside from Memtest86 there's also Memtest86+ and other memory test programs that may use slightly different patterns and fine issues, or high-stress benchmarks may show them, just like your game does. I was recently testing some old hardware before giving it away and discovered that the old AMD processor would throw errors in Memtest86 Pro but only on a certain core and only with specific patterns, and it wouldn't happen in any other diagnostic or test of any kind.

It is also notable that this can be temperature dependent.

Something that passes a few rounds through memory may not pass if you run it all night, or if you have other components also generating heat. Usually you will see crashes if values are not being read back correctly though.

I would not take it as a given it uses the same timings with two or four sticks either. XMP does not specify all timings, if the motherboard is deciding the rest it may very well set some differently depending upon how many slots are populated. I would check hwinfo or similar for actual timings before saying they are the same. Additionally, usually XMP modules sold in pairs of two are only rated for that speed for two modules. You would buy a pack with 4 to do that, and they will be rated lower speed for that use even with identical hardware than they are in a two module configuration.

The board matters as well, as electrically they can either daisy chain it or connect to all slots equally (with a daisy chain being better if you are only going to populate two slots.)

Anyway, weirdness with four modules is common. That is even more true with DDR5.

If they are long stutters, that may be that it failed a checksum or similar and redid something, I wonder if the game has a log you can find which tells you.

If so, that would indicate it is not entirely stable at that speed, so either voltage should go up, the frequency should go down, or relax some timings (more likely one of the first two).

whoisit said:

Timings are set to XMP

Click to expand...

You'll probably need to manually configure settings to back things off just a smidge. Or just drop it down to the next lowest speed in the SPD. I hate that XMP (eXtreme Memory Profile) became the "normal" speed that memory is rated and advertised at rather than being "a bit faster than standard" as it was intended, so you can't just automatically set conservative timings at the full 3200 frequency because the next lowest SPD setting is like 2666. But this will let you immediately identify whether timings are the likely issue. If that fixes is (though your performance will be lower) then you can consider putting it back on the XMP speed and trying to bump the voltage up. Even the minimum increase, probably 0.05V, might be enough to stabilize it.