will a 650w psu be sufficient?

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yes it will be fine you might want z97 board tho because k series cpu wont overclock on h97(it might but not supported by intel) here is what you should do in my opinion if you want to save $ mini ITX route is not the way to go thou.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£171.54 @ Aria PC)
Motherboard: Gigabyte GA-Z97N-WIFI Mini ITX LGA1150 Motherboard (£93.56 @ Scan.co.uk)
Memory: Crucial Ballistix Sport XT 8GB (2 x 4GB) DDR3-1600 Memory (£57.99 @ Amazon UK)
Storage: Crucial M500 120GB 2.5" Solid State Drive (£49.99 @ Amazon UK)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM...
yes it will be fine you might want z97 board tho because k series cpu wont overclock on h97(it might but not supported by intel) here is what you should do in my opinion if you want to save $ mini ITX route is not the way to go thou.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor (£171.54 @ Aria PC)
Motherboard: Gigabyte GA-Z97N-WIFI Mini ITX LGA1150 Motherboard (£93.56 @ Scan.co.uk)
Memory: Crucial Ballistix Sport XT 8GB (2 x 4GB) DDR3-1600 Memory (£57.99 @ Amazon UK)
Storage: Crucial M500 120GB 2.5" Solid State Drive (£49.99 @ Amazon UK)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive (£35.94 @ Aria PC)
Video Card: EVGA GeForce GTX 970 4GB ACX Video Card (£265.16 @ Scan.co.uk)
Case: Cooler Master Elite 130 Mini ITX Tower Case (£36.74 @ Amazon UK)
Power Supply: XFX 550W 80+ Bronze Certified ATX Power Supply (£46.35 @ Amazon UK)
Optical Drive: Lite-On iHAS124-04 DVD/CD Writer (£11.74 @ CCL Computers)
Total: £769.01
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2014-10-03 00:41 BST+0100
 
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