How many Watts do I need to run my new setup?

MegaGherkin

Reputable
May 18, 2015
38
0
4,530
Intel i7 4790K
MSI Z97 GAMING 5 Motherboard
MSI NVIDIA GTX 970 GAMING Twin Frozr 5 Graphics Card
1 x Disc Drive
2TB HDD
256 SSD
2 x Cooler Master SickleFlow Fan

Anyone have any idea on how much I need? I have a a fairly new Zalman 500W from my old PC, is this any good or do I need a bigger one?