You can't overclock the I5-6500 and if it was the gpu you we're planning on Overclocking, there's simply no point, it will simply throttle and destroy every part in your pc. My suggestion is to chuck out every part you have apart from the 1080 .... actually just chuck it too. Also what exactly is it you are wanting to do with this PC besides gaming (if any). SO here's what i would do, upgrade your I5-6500 to a I7-7700k and run it through a Liquid Nitrogen loop with a overclock of 7.5GHz. Next - upgrade your SHITTY Msi 1080 to a sick Gigabyte Gtx 660, buy a Watercooling backplate and shove on that God Given Card, Run the loop through it. Next Buy a Killer Z270-E motherboard, you dont need it for much but if you're wanting to OC your GPU, you will need it.... OBVIOUSLY. For RAM..... You dont need RAM for gaming, That's fake news. You also have too much Wattage so downgrade that card, you *** guzzler....Sorry.
Anyway Here's my suggested build for your $7999 Budget.
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Also - Go **** Yourself