Hi guys,

I'm new to building and I want to do it right first time. I realise that the PSU is one of the most important parts of the build so please help a noob out - Im a single dad of a 2yr old so I can only afford to do this once lol.

Okay so here are the details of the build im about to do (feel free to advise on the list as i have not yet bought any of them YET)

CHASIS: Master Cooler Storm Scout



GRAPHICS CARD: ATI Radeon HD 4890[/b

HARD-DRIVE(S): 2X 500gb WD Caviar (7200rpm)

MEMORY: CORSAIR 3X 2gb DDR3-1600 PC3-12800 CL9 PC (two kits =12gb)


MONITOR: Best Value 23" L-2362WD 5ms DVI HD LCD TFT with speakers

The Keyboard, Dvd-ROM/DVD-RW and mouse are already sorted. WHat Im confused about is this......

If I buy a 1000W PSU, will it work or will it blow he machine up, like wise if I buy a 400W PSU will it just die straight away or will it work okay ?

I understand that I need a Power supply in the range of roughly 550W-750W (I think - please correct me if Im wrong) What Im trying to say is....does the wattage of the psu just mean the max and the psu will work up to that limit or do I have to get a psu that is specific to the amount of wattage I will be using?

I dont want to buy a psu that wont even power the machine up, but also I dont want to buy a really good, high wattage psu and turn it on only to watch the whole thing blow up!!

Im completely new to builds, so Im a little worried about doing ti myself, but I really want to get into this, and I really want to build my own rig.

4 answers Last reply
More about power supply confusion help
  1. to big will not damage your computer, but if you have a 1000w psu putting out 200w then it is not going to be operating as efficiently as it could.

    to small will cause many and varied inconsistant issues.

    the psu you have selected will work fine for what you have selected
  2. If you plan on adding another graphics card for Crossfire down the road, you might want to look at a higher rated PSU--maybe 750w or so. Corsair is a very good brand, nice choice.
  3. The general rule of thumb is a high quality 500 to 500 watt power supply with sufficient current (amps) on the 12 volt rail(s) can easily power a system with any single video card made. A high quality 700 to 750 watt power supply with sufficient current (amps) on the 12 volt rail(s) can power a system with two video cards operating in dual mode. There are a few exceptions like the new ATI Radeon HD 4770, 5850, and 5870 cards which use a little less power due to their energy efficiency.

    Before purchasing a new psu you will need to decide whether you will evdentually have a pc with one or two video cards.

    Corsair, PC Power & Cooling, and Seasonsic are some of the brands that have a reputation for high quality power supplies that consistently earn high marks in technical reviews. They are reliable, stable, and come with a 5 year warranty. Lately we've been seeing a few other brands offering some high quality units.

    The Corsair VX550 you selected is an excellent choice.
  4. Try this:


    Pop your components into this tool, use 85% TDP, 90% load and 25% capacitor aging in the appropriate drop downs.

    Make sure to include case fans and other components and any extras you may be considering for the future.

    When you get the result, that's what your PC will be drawing. For best efficiency and long life, multiply that answer by 1.5.

    The Corsais HX series and Antec Signature series are the "cream of the crop" in my opinion, at least within the realm of what I would consider spending on a PSU. There are advantages in getting case and PSU from same vendor sometimes....at the very least you can be reasonably sure, all the cables will reach where they gotta go.

    A step down from the Corsair HX / Antec Signature are the Corsair TX and Antec TP and I wouldn't go lower than that if you see a 2nd video card in your future. For a single card, the VX series, ir th Antec Neopower series, is just fine however.

    I'd check Tom's HD charts and see if ya can't find a more modern HD w/ better specs. Use benchmarks that are appropriate for your intended usage and don't forget to check the sound and temperature stats.


    I don't think that extra 6 GB or RAM is going to help you any....money be better spent upgrading to a 5850 or 5870.

    Finally, I'd opt for a non stock heat sing / fans ..... especially of you wanna get the most out of that 920 by overclocking it to a moderate 3.67 GHz or so.

    The Prolimatech Megahalems is probably the easiest aftermarket heat sink to install and you can find buy locations here:

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