Cracking sound in powesupply

[Hydrah]

So I was on my pc this morning and all of a sudden it shut down out of nowhere and the power supply made a cracking noise untill I unplugged the powerchord. When I plugged it back in , and pressed the power button again it made another cracking sound for about 3 seconds then stopped. I have a "Silverstone SST-ST1200-G". Is my powersupply broken? Or is my power chord by any chance broken?

 

[Aeacus]

Is the cracking sound similar or same as heard from this video?,
link: https://www.youtube.com/watch?v=Ezk9OA7aKOE

I got to ask, what kind of system you're running that needs to have 1,2KW PSU?

 

[Hydrah]

Is the cracking sound similar or same as heard from this video?,
link: https://www.youtube.com/watch?v=Ezk9OA7aKOE

I got to ask, what kind of system you're running that needs to have 1,2KW PSU?

I took out the PSU and it smelt really burnt. I did sort of hear that yes. Probably only the PSU that's broken.
To answer ur second question, I have dual GTX 780 TI with a 4960x Intel core processor and an Asus IV Extreme motherboard.

 

[Aeacus]

If you're lucky, only thing that is fried is your PSU. Though, we don't know that before you get yourself a new PSU.

Your Silverstone PSU is Strider series and most Strider series PSUs are mediocre quality (Tier three) PSUs.
Silverstone Strider ST1200-G specs: http://www.silverstonetek.com/product.php?area=en&pid=321
PSU Tier list: http://www.tomshardware.co.uk/forum/id-2547993/psu-tier-list.html

For a new PSU, i suggest great quality (Tier one) PSU: Thermaltake Toughpower DPS G RGB 1250W
specs: http://www.thermaltake.com/products-model.aspx?id=C_00002785
newegg: http://www.newegg.com/Product/Product.aspx?Item=N82E16817153270
and reason why: http://www.tomshardware.com/reviews/best-psus,4229.html

If you feel 1,25KW might be too less then go for 1,5KW Corsair AX1500i,
specs: http://www.corsair.com/en/ax1500i-digital-atx-power-supply-1500-watt-fully-modular-psu
pcpp: http://pcpartpicker.com/product/cn3RsY/corsair-power-supply-cp9020057na
reason why is same as above.

 

[Hydrah]

If you're lucky, only thing that is fried is your PSU. Though, we don't know that before you get yourself a new PSU.

Your Silverstone PSU is Strider series and most Strider series PSUs are mediocre quality (Tier three) PSUs.
Silverstone Strider ST1200-G specs: http://www.silverstonetek.com/product.php?area=en&pid=321
PSU Tier list: http://www.tomshardware.co.uk/forum/id-2547993/psu-tier-list.html

For a new PSU, i suggest great quality (Tier one) PSU: Thermaltake Toughpower DPS G RGB 1250W
specs: http://www.thermaltake.com/products-model.aspx?id=C_00002785
newegg: http://www.newegg.com/Product/Product.aspx?Item=N82E16817153270
and reason why: http://www.tomshardware.com/reviews/best-psus,4229.html

If you feel 1,25KW might be too less then go for 1,5KW Corsair AX1500i,
specs: http://www.corsair.com/en/ax1500i-digital-atx-power-supply-1500-watt-fully-modular-psu
pcpp: http://pcpartpicker.com/product/cn3RsY/corsair-power-supply-cp9020057na
reason why is same as above.

So my last question is, as I don't know as much about a pc as to wich components need what power, both the 1.25kw and the 1.5kw can work with my rig? I want to be sure, since I don't plan to buy a PSU that doesn't work with my pc !
Full specs:
RAM: Crucial ballistix Tactical 4x 8GB DDR3-1600
SSD Samsung 840 Evo 500GB (At first i had two of these, but one broke so I just use this one SSD)
Processor: Intel Core i7-4960X 3.6 Ghz
Motherboard: Asus 2011 Rampage IV Extreme
Graphic cards: 2x Nvidia GTX 780 TI 3GB

 

[Aeacus]

1,25KW and 1,5KW PSUs will work just fine in your rig.

When to think about it, those two PSUs are probably too much for your system. Your system may do fine with 850W or 1KW PSU.
To know how much power your system uses, fill out the Outervision's PSU calculator as best as you can,
link: http://outervision.com/b/SVDixX

I already put in the components i know. Since i don't know the cooling and USB devices you use, add those too to get more accurate reading. Just click on the "edit part list in PSU calculator" button to add more components and post the result link here.

For best efficiency, it's best when the load on PSU is between 50% to 80% of total PSU wattage.

An example. Here's power draw of my Skylake build with medium OC on CPU and GPU,
link: http://outervision.com/b/ZYUMdM
Got load wattage at about 481W. Since i have Seasonic PRIME 650 in my system with total wattage of 650W, the 481W is 71% of total wattage of my PSU.