- 66 months ago
Here we have a guy using a 620W power supply with 970s running in SLI (Factory OC'ed) running at around 96% usage each card. His TDP is around 530-540. I believe these watts are being pulled from the wall.
This reminded me that a lot of people believe that a good 1000W Power supply will only give about 800-900W (80-90% efficiency) which is simply not the case. A 1000W (good one) will deliver 1000W to your computer, but the draw from the wall depends on the efficiency. That means a 100% Efficiency would draw 1000W, while a 50% would take 2000W from the wall (excuse my math atm, but the point is the PSU will deliver its rating).
All this post is saying is that if you are worried about spending money on a new power supply in certain cases, you don't have to. You really only have to upgrade if you are throwing in a 4-way SLI system with a huge rad/pump config.
Edit: another guy using SLI 970s and switched to 980s: https://www.youtube.com/watch?v=mdBIZb6VJ_w with a 600w PSU. His PSU was a very good one, but it still shows that an upgrade won't be a problem. (Though I would not recommend buying a 600w PSU when buying a setup for Dual 980s, perhaps a bit bigger).