I've taken a break from mining for a bit and I'm thinking about jumping back in. I'm eyeing a high-end rig with a single strong GPU (like the build here with i9 and 4090).
With all the tech upgrades in mining and the rising difficulty levels, is it actually doable to mine Bitcoin in 2024 with just this setup? How does it stack up against setups with multiple GPUs? Are there any major differences when it comes to profit or efficiency?
Since many years ago, you can not longer mine bitcoin with GPU. If you want to mine bitcoin, at least do research on ASIC which are the machines that generate high computational power that bitcoin miners are using to compete for the blocks. The best ASIC manufacturer that I know is Bitmain. Go and read about their Antminers.
The simple answer is no.
Even the fastest GPU's are no where near good enough to achieve the hash rates required to compete simply adding more GPU's is just hugely inefficient and no comparison to ASIC mining.
Depending on how deep you want to go and if you're just interested in solo-pool mining, you can get entry level ASIC miners like Gekko Science Compac F or Compac A2 that'll do a few hundred GH/s or similarly BitAxe devices offer the same kind of performance with solo its a chance of hitting a block but at much lower energy cost a few 10's - 100's of watts.
If you want to mine for coins PPLNS instead of solo, you'll need a much bigger ASIC miner that'll do 100's TH/s in order to break even these run in the region of 3000+ Watts depending on configuration, Bitmain Antminer's being the most prominent.
You should check out some of the mining efficiency calculators before committing to buy a rig though as you could quite quickly find that you end up in negative equity with it and never recover costs, which is why for entry level solo-pool mining is quite popular.
If that's your plan to mine you are in the wrong place you should go to altcoin(mining) even you have thousands of them you will never be able to beat a Single Asic Usb miner(Compac F) and it will never be profitable.
If you want to mine BTC for learning purposes then try BitAxe by Skot or if you decided to start mining with ASIC units I suggest you read this First time/Small miner reference for getting started..
Actually you can't use GPU to mine BTC and earn profit since 2011 (when FPGA dominate BTC mining). But since you only said "for a while", i would speculate you used to mine using NiceHash or similar software where you mine certain altcoin, but got paid in Bitcoin. If it's what you're looking for, you can visit https://www.nicehash.com/profitability-calculator, enter hardware you use and your electricity cost to see whether it's profitable.
A single powerful GPU isnt as feasible as it used to be. The increasing difficulty and the dominance of ASIC miners which are far more efficient for Bitcoin have made GPU mining less competitive. The power efficiency and hash rate of ASICs simply outclass what even the best GPUs can offer.
This is the answer that OP is probably searching for. Can you mine Bitcoin with a GPU today? Not directly with much success but many people have been mining via Nicehash and for the layman, they aren't going to know the difference. You turn on your GPU, it works, you get paid BTC. I think average people without being Bitcoin addicts would probably consider that Bitcoin mining with a GPU and I think they would have a good point to believe that, even though there is not necessarily any sha256 hashing taking place.