I've noticed that some newer games have unstable frametimes even when I cap them at 60 FPS. My GPU and CPU temperatures and overall usage look fine: the CPU sits around 40%, the GPU often stays below 90%, and neither my 32 GB of system memory nor 12 GB of VRAM is close to full. That makes me wonder whether the game engine—or something I'm not monitoring—is causing the stutter.
Could my memory be limiting performance or hurting my 1% lows? I'm using four 8 GB Kingston Fury Beast DDR4 modules running at 3200 MT/s with timings of 16-18-18-36. It's probably the oldest part of my system, although I assumed it would still be adequate. The rest of the build is a Ryzen 7 5800X and an RTX 3080 Ti. How can I tell whether RAM speed is actually the problem?
2 Answers
RAM speed usually won’t show up as a separate usage percentage. Slower memory can make the CPU wait a little longer, so the result may simply look like slightly lower CPU performance. With the GPU below full utilization and the overall CPU percentage only around 40%, the more likely limit is one or two CPU threads rather than total CPU capacity. Faster DDR4-3600 memory might improve performance slightly, but probably only by a few percent and is unlikely to be the main cause of severe stutter.
Check per-core or, preferably, per-thread utilization while the frametime spikes occur. An overall CPU reading of 40% can still mean that one important game thread is nearly saturated while the other cores have room left. If no individual thread is close to being busy, then the issue is less likely to be a CPU or RAM-speed limit and could instead involve the game engine, shader compilation, asset streaming, drivers, or background activity.
If none of the individual cores or threads are close to full usage during the stutters, does that generally rule out the CPU as the limit?
So I should check whether individual CPU cores or threads are reaching high usage, rather than relying on the overall CPU percentage?