JHmackem
Winger
It can never be overkill. Power in watts is drawn not pushed. So if a PSU that can supply 800w and the CPU/GPU only pulls 600w, that's all that will be used. You'll often see the smoothness of the voltage fluctuate if you pull power near a PSU's rating as well as drop-outs. It gets even more complicated when you have overload on a particular rail when others have little load on them.
Took your advice and amended my order to get the CORSAIR 750W CS SERIES™ MODULAR 80 PLUS® GOLD, ULTRA QUIET, better safe than sorry. I also went for a better CPU Cooler, Corsair H80i V2 Hydro Cooler w/ PCS Liquid Series Ultra Quiet Fans.
My build actually looks vastly different from original one I paid for, but as it's not through to the building stage, I've been able to make amendments. This is my current and hopefully final build...price is about £24.00 more expensive than original, as the saving from removing 16gb of Ram, and dropping the wireless networking card resulted in about £130.00, which was then used on the better mobo, hard disk's, psu, and cooler.
Canny few promotional items out of it as well. Should arrive in about a week.
Case
GAME MAX FALCON BLACK GAMING CASE (RGB LED)
Processor (CPU)
Intel® Core™i7 Quad Core Processor i7-7700k (4.2GHz) 8MB Cache
Motherboard
Gigabyte AORUS Z270X-Gaming 7
Memory (RAM)
16GB Corsair VENGEANCE DDR4 2666MHz (2 x 8GB
Graphics Card
11GB NVIDIA GEFORCE GTX 1080 Ti - HDMI, 3x DP GeForce - GTX VR Ready!
1st Hard Disk
2TB SEAGATE FIRECUDA 3.5" SSHD - UP TO 5X FASTER THAN HDD!
M.2 SSD Drive
128GB SAMSUNG SM961 M.2, PCIe NVMe (up to 3100MB/R, 700MB/W)
DVD/BLU-RAY Drive
12x BLU-RAY ROM DRIVE, 16x DVD ±R/±RW
Power Supply
CORSAIR 750W CS SERIES™ MODULAR 80 PLUS® GOLD, ULTRA QUIET
Power Cable
1 x 1 Metre UK Power Cable (Kettle Lead)
Processor Cooling
Corsair H80i V2 Hydro Cooler w/ PCS Liquid Series Ultra Quiet Fan
Thermal Paste
ARCTIC MX-4 EXTREME THERMAL CONDUCTIVITY COMPOUND
Sound Card
ONBOARD 6 CHANNEL (5.1) HIGH DEF AUDIO (AS STANDARD)
Wireless/Wired Networking
10/100/1000 GIGABIT LAN PORT (Wi-Fi NOT INCLUDED
Warranty
3 Year Standard Warranty (1 Month Collect & Return, 2 Year Parts, 3 Year Labour)
Promotional Item
FREE VR Game Bundle
Promotional Item
FREE FOR HONOR or GHOST RECON: WILDLANDS
Promotional Item
FREE Halo Wars 2
Promotional Item
FREE Steam Voucher!