Hey, I'm interested in the GPU and have been planning to build a mining rig.
How many GPUs can be powered using EVGA 1600 watts PSU?
Also, I'm worried about the noise dB, as I've read on some forums it can get loud?
Depends on what GPU you are using, and what coin you intend to mine. As an example, a GTX 1060 can consume up to 120 W. A Radeon VII can consume up to 300 W. For Ethereum, if you tune it properly, you can usually cut 25%+ off the power usage, but you don't want to use that as a basis, you always want to leave an overhead so you can mine other coins as needed. Also, as a rule of thumb you don't want to use your PSU at more than 80% since it's not efficient that way. So a reasonable expectation is that a 1600W power supply will probably provide about 1200W power efficiently. That will be able to power 4x Radeon VII's (1200W/300W), or 10x GTX 1060's (1200W/120W).
If you have miners inside, noise can be a problem. If it's outside, it's usually not that noticeable.
Mining wattages and efficiency calculations for Ethereum can be found here:
https://docs.google.com/spreadsheets/d/1w6qQtpwzlKRPSx3hYIpTrO1d29SwAIhOV4CNGi3Jk6Y/edit?usp=sharingLet me know if it needs corrections. Thanks.