Will upgrading to 16GB of RAM fix microstutters on an i5-8400?

Yes, 16GB can reduce microstutters on an older CPU like the i5-8400, but don’t expect it to solve everything. 8GB is borderline, and when your system runs out of physical memory, it starts swapping to disk, causing sudden hitches. 16GB gives you breathing room so the OS isn’t constantly fighting for free pages. However, the i5-8400 itself can bottleneck in CPU-heavy scenes, and a slow hard drive or background apps can cause stutters regardless of capacity.