Is 450W PSU enough for this PC?

[SuperBaby]

QUESTION 1:
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I wonder if a 450W power supply unit enough for the following PC:

CPU - Intel i5 3550
Motherboard - Gigabyte Z77M-D3H
Graphic card - Asus HD6670 1Gb DDR5
SSD - Intel 330S 120Gb (Use as primary drive with Windows 7 and other software)
HDD - Western Digital 1TB Caviar Blue
RAM - Kingston KHX1600 DDR3 4Gb
Fan - 2 x 120mm (including one already attached to PSU)
ODD - Liteon 24X DVD-RW
Monitor - Only one 21.5" LED monitor

I seldom use this PC for game. I am not a gamer. It is more for Photoshop and occassion video editing.

Should I get 450W or 500W? What is the disadvntage if I get 500W if 450W is already enough? Do I have to pay more for the elctricity bill or will it burn the parts?

QUESTION 2:
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I want to get Windows 7 Home Premium and the computer shop sells the OEM and RETAIL versions. The RETAIL version is much more expensive. May I know what the difference is?

 

[andrewcarr]

A 450W PSU is more than enough for that computer. If I was buying one I'd get this http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026&Tpk=corsair%20430
Proof that it is enough power for the computer.
http://extreme.outervision.com/psucalculatorlite.jsp
There isn't really a disadvantage getting a 500w since it would allow you more upgrade options in the future (although those are mainly GPU upgrades and since you only want to do photo and video editing it really isn't needed). The difference in power consumption at only 50W difference would be almost insignificant only difference would be initial price.
Since your only using photoshop that GPU you picked should be fine but if you want one slightly better you can pick up a 7750 for only about $10 more and it should be a bit better for photoshop and other video editing software.

For windows 7 you only get the OEM version this includes one install for a computer without any operating system on it. The retail version has three upgrades on it so you need an older version of windows on it already.

Hope that cleared up your questions.

 

[SuperBaby]

Thanks for the reply. I really appreciate it. But I am a bit confused about the OEM and RETAIL Windows 7 disc. The retail version is more expansive while it is only for upgrade? My main concern is whether I can do fresh reinstallation (usingthe same disc) of the W7 OS if my system crashes or infected by virus?

 

[andrewcarr]

If you buy the OEM it will re-install as many times as you want as long as you don't switch out the motherboard. I've had to re-install it a few times and haven't had a problem registering it again.

 

[SuperBaby]

OK. Thanks.

 

[SuperBaby]

Best answer selected by SuperBaby.