I'm trying to diagnose random but very noticeable frametime spikes on my Windows 11 PC. The system has a Ryzen 7 7800X3D, RTX 4070 ROG Strix OC, 32GB of DDR5-6000, and a Gigabyte X870E AORUS Elite WiFi 7 motherboard. Average FPS is usually high and the overall 1% lows aren't terrible, but I periodically get severe hitches lasting around 20–60 ms in several different games.
PresentMon shows that these are primarily CPU-side stalls. For example, one Valheim spike measured 60.87 ms frametime, 60.80 ms CPU Busy, 0.10 ms CPU Wait, 7.20 ms GPU Busy, and 54.19 ms GPU Wait. RDR2 showed a similar result: 53.52 ms frametime, 53.06 ms CPU Busy, 0.46 ms CPU Wait, 9.06 ms GPU Busy, and 42.98 ms GPU Wait.
I've already disabled overlays, removed GPU tuning and overclocks, and updated the graphics drivers. Strangely, heavier games such as Cyberpunk with path tracing can sometimes behave better than lighter games. The issue has appeared in Valheim, RDR2, Subnautica, and occasionally Rocket League, so I'm wondering whether this points to a background process, interrupt or DPC latency, Windows scheduling problem, storage or driver interruption, or some other CPU/game-thread issue. What would be the best way to identify the source of these periodic stalls?
2 Answers
The measurements point much more toward a CPU-side interruption than a GPU performance problem. The GPU is finishing its actual work quickly, then waiting because the CPU or game thread hasn’t submitted the next frame. Since this happens across unrelated games, I’d investigate interrupt and DPC latency rather than focusing only on graphics settings. Monitor CPU usage per core, interrupt activity, and DPC execution times while reproducing the hitch; a driver or background service with occasional spikes may stand out.
It could be a background task briefly occupying the CPU or interfering with the game thread. The fact that this started recently, after possible driver or Windows updates, makes recent software changes worth checking. As a diagnostic experiment, you could test with a different CPU core configuration or temporarily disable a couple of cores and see whether the hitching changes, though that isn’t necessarily a real fix. Also compare behavior after a clean driver installation and with nonessential startup services disabled.
This only started within the last week after I may have installed an Nvidia driver and Windows update. The PC had been stable for the year or two I’ve owned it, so I’m going to compare recent updates and background software as well.
I’m going to investigate interrupts and DPCs next. I tried LatencyMon, but it wouldn’t run because of a driver or Windows security restriction, so I’m also looking for another reliable monitoring method.