GeForce RTX 4090 Founders edition review - Choosing the right power supply

Choosing the right power supply

Ever since the ADA rumours started, there's been a lot of discussion about power consumption and the power supplies needed to AMP a card like the GeForce RTX 4090. First off, let me state all AIBs will deliver a power adapter cable, these however require 4x 8-pin power connectors headed from your PSU. Now, we tested this, but if for whatever miracle reason your PSU would only have 3x 8-pin headers, that'll work ... however, your TGP is then locked at defaults, ~425 Watts so you can't overclock. There's a detection/sense active, the power limiter cannot be increased if you'd opt for this.

Connecting the fourth connector will offer maximum power from your product and opens up tweaking ability on the power limiter. Any (proper) 850W PSU with enough 8-pin headers will work fine if you don't do crazy things with TBP.  Most cards will offer you roughly 500 Watts on the power limiter max. I would not want to go higher either for two reasons, the performance versus efficiency is bad with such a high TGP. Secondly, the fuses of your PSU might not like it :( We assume that if you purchase a 1599 USD graphics card you'll pair it with a proper power supply. 

That said, there's also another development, the new 12VHPWR standard and of course the actual 12VHPWR (12+4pin) connector, as specified by the PCIe 5.0 SIG. be quiet! was the first to ship a test PSU towards us. Meet the Dark Power 13 1000W with a dedicated 600W 12VHPWR connector. While we did not have time to dive deep in it with six RTX 4090 cards to test, we also are waiting on new PSU measurement equipment due to the new 12VHPWR connector.

Some other PSU manufacturers already released PSUs with 12VHPWR connectors, though most use a dongle and the four sense pins are deactivated. be quiet! is working to make its high-end PSU series fully ATX 3.0 compliant. Market-ready models like those shown today will be released by the beginning of next year.

They however like to demonstrate to the public. And aside from all the specifics, doesn't that look much nicer? These new be quiet! units will be released late this year or Q1; for now, we recommend you use your old PSU and upgrade once available (if you'd want that).

Fewer transient power spikes

Last-generation Ampere graphics cards had a lot more issues with transient power spikes. For ADA it looks to be far better than the last-generation Ampere. What's that? Spikes and transients are fast-moving, high-energy bursts lasting for just a few milliseconds and superimposed onto the standard mains power supply.

Above (look at the green line) and RTX 3090 Ti

Above (look at the green line) and RTX 4090. We see fewer spikes. We however are awaiting new PSU measurement equipment to fully test this. Once available we'll post a full review of these new PSUs.