The recently launched GeForce RTX 3090 graphics card is the only 30 Series card to support SLI using Nvidia NVLink. However, as each 3090 has a 350W TDP, you're probably going to need to upgrade your power supply to cope with two of them. SilverStone has a solution, though, in the form of its new DA1650 PSU.
As Tom's Hardware reports, the DA1650 is capable of providing more than enough power for all your components including a couple RTX 3090s. It's an 80Plus Gold rated full modular power supply offering 1650W of capacity. Silverstone used all Japanese capacitors and promises an ultra silent experience (maximum of 36dBA) thanks to the 135mm fluid dynamic bearing fan and semi-fanless operation.
As you'd expect, the DA1650 includes a number of advanced protections including for over current, over voltage, under voltage, over power, short circuits, and temperature. A single +12V rail makes the PSU ideal for overclocking your system according Silverstone, and the power supply is backed by a five year warranty.
At $330, the DA1650 certainly isn't cheap, but if you're looking for a PSU to power not one, but two RTX 3090 cards, $330 isn't a lot to spend to ensure $3,000-worth of graphics cards get all the power they demand. However, if an 80Plus Gold PSU isn't good enough for you, SilverStone is also planning to launch an 80Plus Titanium model in the near future.