Is it safe to use an i5 4690k and GTX 970 on a 450 watt power supply?

Elf_Knight

Honorable
Nov 9, 2013
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I want to upgrade to a Mini-ITX Power Supply because I am going to get either a 1060 or 1070 mini and transition into full mini-itx as opposed to partial ITX. My current PSU is a 500 watt EVGA ATX power supply but it is quite big and taking up a lot of room in my Nano S. I wanted to get a mini-itx power supply since I plan to either mod my current case or design my own or get another ITX case in the future that is more portable. I am currently looking at the SilverStone 450 watt SF power supply since it is within my budget. Otherwise I would save up more and get the Corsair SF 600 watt PSU and overclock my rig. Here are my full system specs:

i5 4690k (non-overclocked)
8gb ddr3 ram
gtx 970 4gb zotac
evga 500 watt psu
msi mini itx lga 1150 motherboard
crucial 525gb ssd
1tb wd blue hdd
corsair h100i v2 on CPU
5 fans (2 on CPU cooler, 1 exhaust, other 2 intake)
1 red LED strip

The case is the Fractal Design Nano S. I used the Cooler Master power supply calculator and it turns out my system only uses 329 watts approximately, so would it be fine on a 450 watt PSU? or should I wait and get a 600 watt one? The main reason is because there's not a lot of room between my graphics card and PSU and also because I want to get a different ITX case in the future and a smaller PSU would help save room. I was looking into a pico power supply but that seems more complicated and risky then its worth.

Many thanks in advance!