Power Supplies

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Beta member
Hi everyone i hope this is in the right section here >< anyway heres what im wondering. If i happened to buy a new case for my computer i would just be able to remove everything from my current case and put it inside the new one right ? As long as everything fitted ofcourse but what about the power supplies? cause they come with ones in them. My power supply at the moment is 350watts but the ones that come with new cases are like 400watts + would it matter running a higher power supply ? or would i just be able to remove that one and put in my original 350 watts ?


Fully Optimized
when it comes to power supplies, the more power, the better. if your computer doesn't need 450 watts, it won't use the full 450, it'll just use what it needs. if you use a power supply thats LESS power than you need, then you have problems. things can get damaged, etc..

depending on the quality of the power supplies, i would get hte more powerful one. powersupplies that come in cases tend to be crappy even if they're rated 500 watts or whatever (unless your case is Antec, and comes with an Antec powersupply, then its fine). if your 350watt powersupply is high quality, and the 450 isn't, then just stick with the 350 watts.

if they're both crap, i recommend you get a good quality powersupply from a good brand. powersupplies are often the cause of system crashes / damaged components. make sure you get a good PSU!

there's a sticky somewhere about good PSU brand names..


Fully Optimized
i found the sticky.. i'll just paste the relevant PSU stuff..

Static_11 said:
If buying a power supply unit

WRITTEN BY STE (inside the ~~~ area)
As was for mentioned, look for weight, if the product does not say how much it is look for the shipping weight that will be pretty close. Anything about 4-6 lbs is a good weight. The heavier the components of the power supply the better quality they are.

You don't have to spend a lot of money for a good power supply the most you would need, as in the cheapest I would go is around 50 to 55$, anything below that usually aren't made with "quality" parts or are very generic power supplies.

To find the right amount of wattage you will need for a computer you can go to a website such as this one and calculate your wattage needs. http://www.jscustompcs.com/power_supply/

However you can use this simple chart to easily figure out what you need.

High End System=520 Watts to 800 Watts Depending
Medium End System=400 watts to 500 Watts Depending
Low End System= 300 Watts to 400 Watts

High End systems
~This includes Servers, Video work stations and Top of the line gamming computers. Or computers with multiple HD and Burners for different needs.

Medium End systems
~systems much like high end but have mid quality parts and or single uses.

Low end systems
~only used for light light gaming, word processing, email and internet use.

With medium to higher end systems you will want to have PFC on your power supply. PFC stands for power factor correction. The power coming into the power supply is not always "clean" there can be variances with frequency and spikes that lower the life span of your power supply and can cause damage to parts if it is not corrected. Active PFC is more efficient then Passive but also is more expensive.

Other aspects of Power supplies, are hold up time and efficiency. Hold up time refers to how long a power supply will continue to produce voltages after the AC input has ceased, it is measured in milliseconds. The longer the better.
Efficiency in a power supply is determined how much of the energy it takes in is actually used and is not wasted in other forms, as with hold up time the higher the efficiency the better, 65 to 70 and higher is recommended, The more efficient power supplies save more money on the electric bill. The efficiency for most power supplies is when it is at highest workload or when the most energy is being drawn from it.

Voltage Rails
~Voltage rails should never straw more then 5% in either direction, that is also what is recommended. If a rail does drop or increase more then 5% of what it should be it can potentially damage and destroy components. This isn't something most companies tell you before you buy it, its something that is bested tested with a Digital Multi Meter (DMM) while the computer is active.

~Obviously Higher systems should have more amps on their rails, for low end systems, with power supplies with only 1 12V rail there should be from 15-17 amps on it, Medium end, 19-24, and 26-35 amps for high end systems. For computers that have a PSU with dual 12V rails or more, 12V1 @ 18-22 or more Amps and for 12V2 the same. The 12V rail is the main concern as it is drawn from the most and is directly connected to motherboard.

As for reliable Brand names
(more Expensive)
PC power and cooling
OCZ technologies

(Medium Priced)

(lower priced)
forton (FPS Fortron)

Some brands I mentioned have higher end power supplies and some lower end ones but for the most part it holds true.

The brands I stay away from and would never recommend. Ever.
~Thermaltake (TT)

The newer ones that I hear are said to be good are Seasonic and eTagean. I have yet to look into them and have heard few reviews and comments.

Generic ones that come with cases are usually listed at their peak wattage not their continuous wattage, which means the power supply may only be a 320 watt continuous but they list it as a 380 watt Power supply, which is its peak wattage. This way they make it look better then it really is.

Those power supplies that look sweet, that glow and flash and are brightly colored are that way for a reason, to sell, they make look awesome but as you will learn these power supplies are only this way cause just about everything else is bad, as in quality of parts, life span and efficiency. There are few power supplies that actually are good performers and look good. They are usually more expensive then people want which is why the cheap crappy ones that look so cool sell a lot. Stay away from these power supplies unless they are made by the name brands I mentioned under good brand names.


~When buying a psu, donÂ’t cheap out. Brand names = good quality even though there more expensive. PSUÂ’s work like this. (my attempt is probably vague but at least IÂ’m trying). If you buy a 500 watt generic PSU and compare it with a ,lets say, 350 watt brand name, the brand name would perform better and last longer. DONÂ’T CHEAP OUT WHILE BUYING YOURSELF A PSU!!!!


Beta member
i used that watts calculator that i got from the link you posted. it cam eup with 261 watts ? so i think the 350watts i have at the moment is enough anyway to handle what im using. its a brand called "omni" i dont know if you've heard of it but i havent had any problems with it so far. so even if the case i buy comes with a crappy power supply that says its like 450watts would it be bad enough to wreck my computer seeing as i would probably only be needing roughly 300 watts ? also a friend of mines power supply blew up once, just wondering what would that have been caused by ?


Fully Optimized
i wouldn't rely on those calculators too much.

omni doesn't sound like a very reliable brand. you'd be taking a risk. if you have high-end parts, i would not risk it!

give a link to the case you plan on buying, and what parts you have.


Daemon Poster
Yeah, those calculators are off. They don't include power spikes, decrease of capacitor power over time, and other factors that can and WILL come into play with a PSU and computer hardware.
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