Should I get a power supply that is far over my estimated wattage or a little bit above it?
The PSU has to have at least and preferably more the required amps on the 12v rail. Also consider that a PSU runs at its highest efficiency when at 50~80% capacity. in you build in the other thread, for the 770 you need at least 42 amps on the 12v rail and a with an OC'd i7 you'd want a 650W PSU. Always get a little more than you need for load headroom and higher efficiency. This will suit it well:
Ideally you want psu to be 25-50% over your full load. Anymore your just wasting electricity. So to answer the age old question: bigger isn't better.
Bigger is almost always better. If you buy 1200W PSU you wont waste electricity but most likely save so all it comes to PSU efficiency not watt ratings. Also PSU working at 50% load will have better efficience and pruduce less heat then PSU working at 90%.
If money are not a problem the best for like 400-450W system is something like 850W gold+ PSU
No bigger isn't better at all, usually the opposite in most cases.
Your understanding of PSU efficiencies isn't correct either, which is why you never see pc's with over 850 watts unless they sli. For example an oversized psu running at 10% capacity is not efficient at all. No more than running a school bus with 4 passengers would be.
Did you ever look at any PSU review? Lets compare XFX 550W vs 850W.
550W with 70W load =76% 420W load 83% eff
850W with 70W load =76% 420W load 85% eff
Also I said if money are no problem and you are not on tight budged the higher wats will be better because it will run cooler and more silently.
550W 445W load 33 decibels and +8C temp
850W 450W load 30 decibels and +4C temp
If you ever look on eff. charts and temps you will know the best spot is arround 50-60% load.
And even if you get better eff. at idle you will save like 5 wats but loose like 20W at load.
Majority of sites say 25-50% above full load. Not 100-150% like a 1200 watt would be, which case your efficiency wouldn't be good. And this has nothing to do with being on a tight budget ($1500-3000 builds are not using 1200 watts psu), so your not right here either.
Also my 760 watt hybrid seasonic is always silent. The fan only comes on when needed, which is never since I don't overclock. When I switch it to on mode, the fan is half as loud as my cpu fan anyways, so you wouldn't hear it.
The person asked if its bad to have higher watt PSU and the only bad part is price.
Im not forcing nobody who dont play games to buy 1200W PSU but decent pc load is around 400-450W so you saying 550W PSU is better then 850W just because its cheaper?
25-50% above full load is fine but above 50% is better not worse it will just cost more money but it will be better.
Also if you have 760 platinum PSU and use 330W while gaming you are at 43% load so that's 130% over and you recommended 25-50%.
I didn't recommended getting 1200W PSU but 750-850 is perfect for high end gaming and leaving a option to go SLI in the future.
haha nice analogy at the end
Take the 12v rail amps and multiply it by 12. For example: corsair cx600 46 amps on 12v rail.
(46A x 12 = 552 watts available for gpu/cpu/motherboard/ram)
The calculator on pcpartpicker website is fairly accurate. So you want to at least have 50w-100w over the calculator and if sli/ crossfire then 100w+ extra.
What CPU and GPU do you have?
If you have something like a $300-$400 GPU and a haswell i5, I would get a 650W or a quality 600W.
My CPU is an i5 4670K and my GPU is an nvidia GTX 770
Then I would also recommend this unit: