The Thermaltake ToughPower GF3 850 achieves good overall performance, but that is not high enough to dethrone the Corsair RM850x and the EVGA 850 G7.
But the GF3 850 hides an ace up its sleeve; it is ATX 3.0 and PCIe 5.0 ready. Nvidia's RTX 4000 series might not require ATX 3.0 PSUs and 12VHPWR connectors to operate, but it is good to be as future-proof as possible because PSUs can outlive several GPU generations.
From now on, we will see more and more ATX 3.0 compatible PSUs featuring 12VHPWR connectors. Such PSUs are tolerant to dreadful power spikes, reaching up to 200% of the PSU's max power. This is an overkill feature for the current generation GPUs, at least, but you cannot know what the future will bring. We strongly advise you to invest in an ATX 3.0 PSU. Still, if you find a good bargain on a previous-generation PSU, you could go for it, considering that the RTX 4000 graphics cards can operate with the provided adapter cables. The use of adapters is not ideal since they allow for higher voltage drops, especially under high loads, but this is the most affordable way to retain compatibility with PSUs that don't have 12VHPWR connectors.
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Disclaimer: Aris Mpitziopoulos is Tom's Hardware's PSU reviewer. He is also the Chief Testing Engineer of Cybenetics and developed the Cybenetics certification methodologies apart from his role on Tom's Hardware. Neither Tom's Hardware nor its parent company, Future PLC, are financially involved with Cybenetics. Aris does not perform the actual certifications for Cybenetics.