Have you looked at the power supply cables. There are 3 cables. ie a TWO 2x2 block used for the Main and CPU power. The third is a 7 pin inline for the PSU fan connector. You options to upgrade the PSU are not available.
This system is feedback driven thru Solution and Kudo flags. It's the only means of knowing if you have been served. Please click Accept as Solution, if your problem is solved. To say THANK YOU, press the "thumbs up symbol" to render a KUDO. You can render both Solution and KUDO..
HP Envy 8 5010 Tablet (2) HP DV7t i7 3160QM 2.3Ghz 8GB Printer -- HP OfficeJet Pro 8620 Legal Custom Asus Z97D, I7-4790k, 16GB RAM, WIN10 Pro 64bit, ZOTAC GTX1080 AMP Extreme 3 fan 8GB RAM, 500GB SSD, Asus PB287 4k monitor, Rosewill Blackhawk case and 750W OCZ PSU.