I'm trying to decide if my current 750W power supply will be enough to support an upgrade to an Asus ROG Strix RTX 3090. Right now, I have an RTX 3080, a Ryzen 5 5600G CPU, and some pretty decent components like a B550 motherboard and 64GB of RAM. I'm planning on using the 3090 for AI image and video generation, not gaming. Some friends say it should be fine—even one friend is running a 3090 on a 650W PSU—but I've encountered mixed opinions online. Would undervolting help? Any advice would be much appreciated!
3 Answers
Ideally, I’d recommend an 850W PSU for a little more power headroom, but you could manage with 750W especially if you undervolt. The 5600G doesn’t draw much power, so you might be ok as long as you’re mindful of your total load.
A good quality 750W PSU can handle the RTX 3090 just fine. The GPU’s sustained draw is around 450W at peak, and your system won't pull more than about 150W. Just be mindful of power spikes, which can sometimes reach above that. Also, make sure you use two separate PCIe power cables for the GPU, and undervolting can help too!
Yeah, you should be alright, but I would advise you to undervolt the card. This not only helps with power consumption but can improve thermals. Just keep an eye on those power spikes, as 30 series cards can be known for that. A bit of caution can go a long way!

Thanks for the heads-up about the power spikes! I'll consider undervolting.