As you'd expect, dropping the resolution to 1440p tends to narrow the gap between the RTX 3080 and the other GPUs. Given the level of performance we're talking about, 1440p gaming on the RTX 3080 is going to be similar in many ways to 1080p gaming on an RTX 2080 Ti. You can do it, of course, but you'll almost certainly start to hit CPU bottlenecks in a lot of games.
Our high level overall average charts show most of what you'll want to see. At 1440p ultra, the RTX 3080 ended up 24% faster than the 2080 Ti, 43% faster than the 2080 Super, and 54% faster than the 2080 FE. Or if you're still hanging on to a GTX 1080 from 2017, it's more than twice as fast — a reasonable upgrade option. It's also twice as fast as the RX Vega 64, 74% faster than the RX 5700 XT, and 67% faster than Radeon VII.
CPU bottlenecks become even more of a factor when you drop to 1440p and medium settings. You can knock ~10-15% off the 3080's lead over the 'slower' GPUs like GTX 1080, ~10% off the lead over the cards in the middle of our charts, and only ~5% less against the top previous-gen cards, like the 2080 Ti. Again, all of that is thanks to the 3080 becoming increasingly CPU-limited.
We're going to dispense with discussions of 1440p performance on the individual games since there's really not much to add. The RTX 3080 still easily reigns as the fastest 1440p gaming GPU. It did come in slightly behind the Titan RTX at 1440p medium in Forza Horizon 4, but both cards were clearly smacking into an fps ceiling of some form.
Borderlands 3
The Division 2
Far Cry 5
Final Fantasy XIV
Forza Horizon 4
Metro Exodus
Red Dead Redemption 2
Shadow of the Tomb Raider
Strange Brigade