Need help buying a new PSU

usually these kinds of problems are caused by the motherboard, but if its working, its probably the PSU. while the corsair unit will probably fix it, it's WAY overkill, and a regular 600-750 80+ gold unit will be a much better value:
https://pcpartpicker.com/part/seasonic-power-supply-ssr750rm

You want a quality PSU. Your best bet is getting a GS 650w from EVGA.

PCPartPicker part list / Price breakdown by merchant

Power Supply: EVGA SuperNOVA GS 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($59.99 @ NCIX US)
Total: $59.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-05 14:13 EDT-0400

Agreed that the 860w Corsair is way overkill as well as way overpriced.

600-650w unless you intend to run SLI in the future in which case 800-850w is recommended. The Corsair is still a poor value.

Look for Seasonic, XFX, Antec, or EVGA's B2, G2, or GS units

550w quality unit will be sufficient for your build. in case you would like to SLI in the future 750w will be enough.

PSU tier list : http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html

These are great deals :
550w EVGA SuperNOVA GS 550W 80+ Gold - http://pcpartpicker.com/part/evga-power-supply-220gs0550v1 - tier 1 unit.
750w EVGA 750W 80+ Gold - http://pcpartpicker.com/part/evga-power-supply-220g20750xr - tier 1 unit.

Take a look : http://www.guru3d.com/articles-pages/geforce-gtx-980-sli-review,4.html

So... just to toss a different perspective on things in here — your system won't actually draw more than 350 watts even when stress testing. A quality 450-550 watt PSU would be just fine for you. You'll notice 650 watt PSU's often have 4x PCIE connectors - because they're designed with SLI systems in mind. I do not have a good explanation for why people are constantly recommending PSU's which are twice as powerful as is needed. They usually say something like "If they want to add a second GPU" or something. I tend to think of SLI as something maybe 1 in 30 gamers actually do — with most preferring to pick up the latest and greatest single GPU when it's time for the next upgrade.

I do not agree that 450w enough for this " i7 4790k 4ghz, 16gb ram, geforce gtx 980 4gb, 3 hdds, 1ssd."

550w is the minimum I would recommend. I recommended 600-650w in case he wanted to overclock the i7 as high as possible.

Well, I just put the system together on pcpartpicker.com and it estimates the wattage at 403, which I can pretty much guarantee is high, considering that when similar systems are reviewed (with a typical 4.2-4.4Ghz overclock) they draw about 300 watts during gaming. Even if it were drawing 400 watts, though, I'd be curious as to why you would want an extra 200-250 watts available for overclocking the CPU. I can understand an extra 50, but if this were the kind of guy who was after 5+ Ghz overclocks the chances are he wouldn't be here asking for advice on picking a PSU (especially without making any mention of overclocking).

For example:
http://www.anandtech.com/show/8526/nvidia-geforce-gtx-980-review/9 (test system with higher TDP CPU at 4.2 Ghz)
http://www.anandtech.com/show/8526/nvidia-geforce-gtx-980-review/21 (idle and load power, temp and noise figures barely exceed 300w)

Hello AndyJF3000,

Take the following example setups:

Wattage Breakdown with single GTX 980:

Component Estimated Wattage
ntel Core i7-4790K 4.0GHz Quad-Core Processor 11W - 88W
Corsair H100i GTX 70.7 CFM Liquid CPU Cooler 10W - 15W
Gigabyte GA-Z97X-UD3H-BK ATX LGA1150 Motherboard 17W - 70W
G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1600 Memory 18W - 18W
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive 4W - 20W
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive 4W - 20W
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive 4W - 20W
Samsung 850 EVO-Series 250GB 2.5" Solid State Drive 1W - 5W
MSI GeForce GTX 980 4GB Twin Frozr Video Card 41W - 165W
Total: 110W - 421W

The above setup with single GTX 980 needs only 421W max.

Wattage Breakdown with 2 x GTX 980 in SLI:

Component Estimated Wattage
Intel Core i7-4790K 4.0GHz Quad-Core Processor 11W - 88W
Corsair H100i GTX 70.7 CFM Liquid CPU Cooler 10W - 15W
Gigabyte GA-Z97X-UD3H-BK ATX LGA1150 Motherboard 17W - 70W
G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1600 Memory 18W - 18W
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive 4W - 20W
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive 4W - 20W
Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive 4W - 20W
Samsung 850 EVO-Series 250GB 2.5" Solid State Drive 1W - 5W
MSI GeForce GTX 980 4GB Twin Frozr Video Card 41W - 165W
MSI GeForce GTX 980 4GB Twin Frozr Video Card 41W - 165W
Total: 151W - 586W

The above setup with 2 x GTX 980 in SLI needs only 586W max.

The first most important thing in selecting a PSU is to see how many Amps it can deliver in its +12V rail, besides wattage. A single GTX 980 only require a quality 500/520W PSU that can deliver 30Amps on its +12V rail.

All you need is solid quality "Tier 1" or "Tier 2" 80+ Gold/Bronze Certified 550/650/750W PSU.

So consider either of these quality PSUs:

For single GTX 980 and have no plans to get another GTX 980 in future:

PCPartPicker part list / Price breakdown by merchant

Power Supply: Antec High Current Gamer 620W 80+ Bronze Certified Semi-Modular ATX Power Supply ($64.99 @ NCIX US)
Total: $64.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-05 14:51 EDT-0400

The Antec 620W can deliver 48Amps on its +12V rail, which is more than enough for your rig with single GTX 980.

For single GTX 980 and have plans to get another GTX 980 in future:

PCPartPicker part list / Price breakdown by merchant

Power Supply: SeaSonic G-750 750W 80+ Gold Certified Semi-Modular ATX Power Supply ($104.99 @ NCIX US)
Total: $104.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-07-05 15:02 EDT-0400

The Seasonic 750W can deliver a mammoth 62Amps on its +12V rail, which is more than enough for your rig with 2 x GTX 980 in SLI.

Both these quality Semi-Modular PSUs comes with 5 year warranty.

Cheers!

Take a look at the i7 4770k/4790k's average power consumption under load

http://www.tomshardware.com/reviews/core-i7-4790k-devils-canyon-overclock-performance,3845-9.html


Now lets's take a look at the GTX980's average power consumption

http://www.tomshardware.com/reviews/nvidia-geforce-gtx-980-970-maxwell,3941-12.html



The i7 + 980 alone can use almost 450w under load

The first chart you linked was total system power draw over a series of tests with a GTX Titan installed, so the average includes not only a lot of idle time for multiple cores, but also feeding the Titan during segments which required GPU contribution. It was only really useful for comparing the CPU's they were testing against one another, not for determining the total draw of a CPU. The main difference between their build for that test and this build is that the OP's has 3 extra HDD's and a GPU which uses far less power.

So yes, if you look at the tip-top spike of the GTX 980 somehow pulling 300 watts for a brief moment, then estimate 150 watts for the CPU/Memory/Motherboard, you get to 450 watts. With all 3 HDD's working at once (RAID 5?) you'd be up to 510 watts as a maximum split-second spike. In that case yes, a 550+ watt PSU may be the safer option, but if it were me I'd happily put that system on a Seasonic Platinum 460 Fanless if that's what I had sitting around (granted that PSU made no complaints when tested at 110% load).