https://www.techpowerup.com/272156/seasonic-details-12-pin-modular-cable-free-for-geforce-30-series-owners
 
Seasonic today shared with us some additional details regarding its 12-pin Molex MicroFit 3.0 modular PSU cable, and how it plans to market it. If you've read our NVIDIA GeForce RTX 3080 Founders Edition Unboxing Preview, you'll know that NVIDIA ships its Founders Edition cards with a printed warning not to use any third-party adapters to convert 8-pin PCIe power connectors to the 12-pin connector. The warning also asks you to use the included adapter, and that using a third-party adapter would void the warranty. There's no clarity from NVIDIA on whether modular cables that plug directly into a modular PSU and put out 12-pin connectors strictly fit this description, as they're not "adapters."

Seasonic believes that its cable is a perfect match for NVIDIA's GeForce RTX 30 series graphics cards. The cable uses 16 AWG wires. Each 12 V pin of the connector is rated for 9 A current, which means the cable is capable of ferrying up to 540 W of power. On one end of the cable are two 8-pin 12 V connectors (which plug into the 12 V modular back-plane of your PSU), and on the other is one 12-pin connector. The cable is 75 cm in length. The cable is compatible with the company's Prime, Focus, and Core series modular/semi-modular PSUs.
 
If you own a Seasonic PSU (Prime/Focus/Core) and an NVIDIA GeForce RTX 30 series graphics card that has a 12-pin input, then you're eligible to receive the cable free of charge. Later this week, on Wednesday, the Seasonic website will have an online form with which you can request the cable. You'll have to provide the serial number and a photo of the PSU, and proof of purchase and serial number for the GeForce 30 graphics card.

Certain RTX 30 series graphics card SKUs ask for 750 W (or higher) PSUs in their system requirements; while certain other RTX 30 series cards mention 650 W in their system requirements. Be sure that the PSU you're seeking your modular cable for meets the system requirements of the graphics card you own. Seasonic mentioned that it has limited supply of the cable, and hasn't yet decided if they want to sell the cable in the open market. The company will take a call on this by year-end.
 
I personally feel safe about the 540 max watts of power this cable can support. 
 

Real nice gesture from Seasonic.

Free. 👍

You would think if Nvidia was  going to put this new connector on their cards, they would have worked with at least some of the big name PSU companies to get some certification/ specs in place for them to be made by them ....