What should I upgrade first in my gaming PC: CPU, GPU, or power supply?

Don’t choose the graphics card without checking the power supply. Some people may run a low-power card on 450W, but for a substantial upgrade I’d replace the PSU with a reputable 650W or 750W Gold-rated model. That gives you more headroom and avoids stressing an older unit. You probably don’t need to replace the motherboard or RAM unless the board lacks BIOS support for the CPU you want or you’re planning a completely new platform.

If you want a larger jump in graphics performance, a newer card such as an RX 9060 XT-class card would make sense for 1080p and some 1440p gaming. A higher-end card like an RX 9070 or RTX 4070-class model is better suited to 1440p, but it would be excessive for a typical 1080p setup. Pairing a powerful GPU with the current processor may still leave you CPU-limited in games like Fortnite and Counter-Strike.

The Ryzen 5 3350G is probably the biggest limitation, especially for minimum FPS and frame consistency. A Ryzen 5 5600 would be a strong value upgrade, while CPUs like the 5700X3D or 5800X3D offer more gaming performance if you can find them at a reasonable price. Check your motherboard model first and make sure its BIOS supports the new processor. The GTX 1660 is still usable for 1080p, so I’d consider upgrading the CPU before replacing the graphics card.

For a budget-focused upgrade, look at a Ryzen 5 5500 or 5600 and a used RX 6600 or RTX 3060. Those cards are good fits for 1080p and don’t put as much demand on the power supply as higher-end options. The RX 6600 in particular should be manageable with a quality 450W unit, but confirm the exact PSU model and condition before relying on it.