How much gaming performance would I gain moving from an i5-10600K to a Ryzen 7 5800X3D?

Resolution makes a big difference. At 1080p with competitive settings, the 5800X3D can deliver noticeably higher FPS, especially in esports and simulation games. At 1440p, the improvement is usually smaller, and at 4K the RX 6700 XT will normally be the limiting component, making the CPU change difficult to notice.

Remember that moving from the 10600K to a 5800X3D requires an AM4 motherboard and uses DDR4 memory, so you can’t just swap the processor. The 5800X3D is also an older chip and can be expensive, so compare the total cost against a newer platform. Lower-end Ryzen 5000 models such as the 5500 or 5700 are not equivalent replacements for the 5800X3D in gaming; their cache and performance are substantially different.

The exact gain can’t be calculated without knowing the games, settings, resolution, and your target frame rate. Check GPU usage while playing: if the GPU is already near 95–100% at your desired FPS, a CPU upgrade won’t help much. If GPU usage is low and one or more CPU threads are maxed out, the 5800X3D could make a meaningful difference. With this graphics card, a rough estimate might be anywhere from almost nothing to around 5–10% in GPU-limited games, with larger gains in CPU-limited titles.

With an RX 6700 XT, the upgrade probably won’t produce a huge average-FPS increase in most modern games. You’re more likely to notice smoother frame times and better 1% lows, especially in CPU-heavy or competitive games. If your current performance is already good, it may be better to wait and upgrade the GPU first—or upgrade both platforms later.