What GPU upgrade makes sense with an overclocked i7-9700K?

Since you prioritize high-refresh FPS gaming, don’t choose solely based on a theoretical bottleneck percentage. Check benchmarks for the games you actually play, and consider a per-core CPU overclock rather than only an all-core overclock. Some games benefit from strong single-core performance, while others are mostly GPU-limited.

The RX 9060 XT 16GB is worth considering if you want a newer card with plenty of VRAM without going too far beyond what the CPU can feed. The XFX Swift OC version is a decent value-oriented model, although compare prices, cooler reviews, and warranty coverage before buying. Overclocking the GPU probably won’t make a huge difference if the CPU is already the limit.

For this CPU, I’d generally look around the RTX 4070 Super or RX 7800 XT level at most, with the understanding that the result depends heavily on the game, settings, and resolution. At 1080p and very high refresh rates, the 9700K will become the limiting factor more often than it would at 1440p or 4K. A Radeon RX 9060 XT 16GB would also be a reasonable, more balanced upgrade if you want to avoid overspending before your eventual platform rebuild.

A used RTX 2080 Super, RTX 2080 Ti, or something in between the 2080 Super and RTX 4070 would pair fairly naturally with the 9700K. A faster card can still improve performance, but at 1080p high refresh the CPU may prevent it from reaching its full potential in some games. That doesn’t mean the card is unusable—it just means the benefit varies by title.