How the Power Supplies, Motherborads and PC cases are related to each other? And how they are compatible?

xyzx

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Feb 3, 2014
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Hi guys,
After a long time with laptops, I decided to buy a desktop computer.
Everything was fine until the moment when I start to think is that the right power supple or I have to get the more powerful, is that power necessary. So, the things become more and more confusing.
My ideology for choosing one to another is to match their similarities, for example:
CPU socket: 2011 => motherboard with socket 2011.
However, these Power Supplies doesn't seem right to me, what is the difference between 500 or 750 Watts supple? I mean the CPU eats 130 watts, the GPU eats around 100 and all other component eats 100-200, so what is the idea of 500+ watts?
One more thing that bothering me is the PC case:
Is there a difference between all PC cases, some of them have USB 2.0 but other have 3.0. So, when the motherboard supports 3.0 and the case only 2.0 is there a way to use the 3.0 but at the back of the PC?

Finally, my decision was to get an average power supply, the most cheap PC case and GPU, but with a good CPU, SSD, Motherboard and RAM.

CPU
http://ark.intel.com/products/77781

Motherboard
http://www.gigabyte.com/products/product-page.aspx?pid=4050#ov

Power Supply
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139048

Memory
http://www.crucial.com/store/partspecs.aspx?IMODULE=BLE4G3D1608DE1TX0

PC Case
http://www.plaisio.gr/ypologistes-anavathmisi/anavathmisi-ypologisti/pc-cases-koutia/Turbo-X-Case-A13-Piano-Black-Midi-A1013.htm

GPU
http://www.sapphiretech.com/presentation/product/product_index.aspx?pid=316&lid=1

SSD
http://www.amazon.com/Samsung-Electronics-Series-2-5-Inch-MZ-7PD256BW/dp/B009NB8WRU

Are these components will fit?
Thanks in advance!

Update:
Thanks to @Illumynization and @Cons29. I found my solution in their both answers because they are answering a different parts of the question.
 
Solution
these things are standard (unless you are trying a 10yr old psu on a new motherboard)

for the power, 500-600w is enough for a typical setup. Around 750-800 for those that have SLI/XFire (using 2 gpu's)
a typical setup eats around 300-400w of power. yes 500w is more than enough but we don't want to push it to the limit, also, capacitors do age (i just read this somewhere), so we take that into account also. Good brands are Corsair, seasonic, among others. Stay away from those that come with the case

even for the case, the screw holes for example, these are standard as well. So you really don't have to worry about them.
about usb, they are backward compatible.
these things are standard (unless you are trying a 10yr old psu on a new motherboard)

for the power, 500-600w is enough for a typical setup. Around 750-800 for those that have SLI/XFire (using 2 gpu's)
a typical setup eats around 300-400w of power. yes 500w is more than enough but we don't want to push it to the limit, also, capacitors do age (i just read this somewhere), so we take that into account also. Good brands are Corsair, seasonic, among others. Stay away from those that come with the case

even for the case, the screw holes for example, these are standard as well. So you really don't have to worry about them.
about usb, they are backward compatible.
 
Solution

Illumynization

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Nov 12, 2013
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A motherboard with a USB 3.0 header means that if you buy a case with USB 3.0 ports on the front or top, you will be able to use them by connecting the front/top panel I/O to the motherboard. Regardless of what motherboard you get, you will be able to use the ports in the back.

The higher wattage power supplies are for builds that require a lot of power. GPU's and multi GPU builds tend to eat up a lot of power so the users would need a large wattage power supply. In your case, a small typical wattage will do as your parts don't draw too much power.
 

xyzx

Honorable
Feb 3, 2014
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10,510


I'd like to pick your answer as solution too. Thank you!