The NVIDIA GeForce RTX 5090 is one of the most power-hungry graphics cards in the world. With a base TGP of 575W, you need a very powerful power supply to run it. However, the latest leaked prototype of the RTX 5090 suggests it could have been even more demanding. Four Power Connectors for More Power https://twitter.com/yuuki_ans/status/1926903505274433943 According to the leak that includes a photo of an early prototype of the RTX 5090, this version of the card had no less than four 16-pin power connectors. This setup would allow the card to draw up to a shocking 2,400W of power,
Nominally EU voltage is 230V, and may be 240V. In fact, it can be as high as 230V +10% = 253V. Higher voltage means more power for a given current, so nominally it’s 16A x 230V = 3.68kW, but you could have say 16A x 250V = 4.0kW.
If your sauna is 400V then it sounds like you’ll be 230V (400V / sqrt(3) = 230). But the voltage can also be 230V -6% = 216V, so 220V is within scope.
But yeah, standard voltages in the EU are either 230V/400V or 240V/415V. They’ve been harmogenised, but if you look at the numbers you’ll see the trick - 230V +10% is roughly the same as 240V +6%. So the range is 230V-6% and 240V+6%.
You’ve got a 3 phase connection though so you might find you’ve got different single phase breakers on different phases (eg lights on one phase, sockets on another), with slightly different voltages for each one.