I built this PC about ten years ago and it is starting to struggle in newer games such as Call of Duty and Forza. Because component prices are high, I would prefer to upgrade only the graphics card, and possibly the power supply if necessary. I play at 1080p and 60 Hz and do not plan to replace my monitors soon. My current system has an Intel Core i5-6600K, Gigabyte Z270 Ultra Gaming motherboard, 16GB of DDR4-2666 memory, a Sapphire Radeon RX 480 4GB, and an EVGA 650W Gold power supply. Would a newer GPU be heavily bottlenecked by the four-core CPU? Will running a PCIe 4.0 graphics card in my motherboard's PCIe 3.0 slot significantly reduce performance? Is switching from AMD to Nvidia difficult? Would my 650W PSU handle a modern card, and should I consider a used higher-end GPU such as a 3080 or buy a newer midrange card within a $300–$400 budget?
4 Answers
The i5-6600K's four cores and four threads will be the biggest limitation in many newer games. A GPU upgrade will still be a major improvement over the RX 480, but you may run into low minimum frame rates and stuttering, especially in CPU-heavy titles. A used GPU is probably the best value, but I would avoid spending heavily on an extremely powerful card unless you plan to replace the rest of the system soon.
Look at used cards such as a 6700 XT, 6800, RTX 3070, or a reasonably priced 3080. They would all be huge jumps from the RX 480, although the CPU will hold them back in some games. Newer midrange cards may use less power and offer newer features, but buying a more modest used card and saving for a complete platform upgrade could make more sense for a 1080p/60Hz setup.
If the EVGA unit is a good-quality 650W model and is still healthy, it should handle many midrange upgrades. A 3080 can have significant transient power spikes, though, so I would be more comfortable with a newer 750W-quality unit for that class of card. There is no need to replace the PSU automatically just because the GPU is newer.
PCIe is backward compatible, so a PCIe 4.0 card will work normally in a PCIe 3.0 slot. At 1080p, the performance difference should be negligible for the cards you are considering. Moving from AMD to Nvidia is also straightforward: uninstall the old graphics drivers, install the new card, and install the appropriate Nvidia drivers.
A used 6th- or 7th-generation i7 could provide a small improvement if you find one very cheaply, but those processors are still old and often overpriced. I would not spend much on a 6700K or 7700K; save that money for a newer motherboard, CPU, and memory instead.