I thik I need more watts

  Jimijim 21:09 08 Jun 2009

Hi everyone

My computer died the other day. A man in a shop replaced the 400w PSU with a 300w PSU. Now it powers up when I disconnect one or other of my hard drives (one 160gb SATA, one 60gb non SATA... older), but will only boot up with one disconnected.

He claims it is not the fault of the PSU but I'm not convinced, having looked at forums etc. Here are my rough specs:

Dual core processor.
Nvidia 8500 gt graphics.
SoundBlaster Audigy Platinum.
DVD rewriter.
1gb ram.
Hard drives as above.

What does anyone think? I'm tempted to buy a half decent 400w PSU to see if that will make a difference. Both drives coexisted happily before the PSU fried.

Thanks for looking.

  OTT_Buzzard 21:20 08 Jun 2009

300W sounds very low indeed, especially if it's an unbranded generic PSU.

There's not enough info on your PC spec to tell for sure, but if you click here and fill in the details it will give an indication.

  Jimijim 21:44 08 Jun 2009

Hello there.

Thanks for your reply.

It seems that the minimum recommendation is 300-350w. Since he's put in a generic PSU, do you think it doesn't have enough juice to power both hard drives?



  OTT_Buzzard 21:49 08 Jun 2009

It's gonna be borderline if you're that close to the minmum recommended. If you can avoid running both hard drives off the same output from the PSU it *may* help.

All that said, not all generic PSU's are that bad, and the one's that are tend to be bad once they get hot, which is unlikely to be a problem on first boot up of the day.

  Jimijim 21:54 08 Jun 2009

Yes I see what you mean. I'm just a bit annoyed with the guy who 'fixed' it because when he gave it back to me, both drives were connected and so it wouldn't boot up.

I don't see how I can avoid running both drives from the same output... is there an alternative?

That said, changing a PSU seems pretty straightforward. If my laptop hadn't gone down in the same week I'd have Googled it and had a go myself.

I might just buy a better, quieter PSU and see what happens.

if it's running that close to the edge, something will give and it may cost more than a good psu. dont risk it put something good in.

  Fruit Bat /\0/\ 22:02 08 Jun 2009

If renewing a PSU check:

1. The physical size of your PSU, some are hard to replace due to being a non standard size.
2. The amount of power need from the PSU don't skimp.
3 The correct connections for your equipment

1. Physical Dimensions

Besides the specs and form factors, the physical dimensions are also important factors in selecting a compatible power supply. Here is an outline of the physical dimensions of most standard power supplies:

# ATX: 6x3.5x5.5", HxWxD. Most common. Uses 4 mounting screws.
# Mini-ATX: 5x3.5x5", HxWxD. Rare size. Uses 4 mounting screws. Can be used in a regular ATX case, but often not the other way around.
# MicroATX: 5x3x4", HxWxD. Use 3 mounting screws. Not interchangeable with ATX or miniATX.
# Flex ATX: Even smaller than Micro ATX. Various sizes according to case specs; often not interchangeable.

Use the data above to determine if a particular power supply would fit your case.

The quality of a power supply can be estimated by its weight. While this is not a true scientific or thorough measurement of the power supply reliability, it is nevertheless a very simple and easy way for ordinary PC users to estimate and compare the quality of a power supply. Why weight matters click here

2. Power supply calculator click here

3. Correct connections
Some boards have 20 pin connectors others 24 pin
There is often a 4 pin plug required to power Intel CPUs
Molex D plugs for IDE HDD and CD/DVD drives
SATA power connections for latest HDDs and DVD drives.

Guide to changing PSU
click here
click here

  citadel 22:07 08 Jun 2009

its best to get a quality psu with the 80% + logo, these waste less electricity and have better components.

  Jimijim 22:13 08 Jun 2009

Hello fellas

I can't thank you enough for your valuable input.

Tomorrow I shall boot up the desktop, do a proper power calculator, and hunt around for a quality 400w psu. Even if it doesn't fix the two hard drives problem, I'll feel better about the machine itself, efficiency and reliability wise.

Fruit Bat, I'll send you some fruit for your excellent response.

Cheers Adman and Buzzard.

Will repost when psu is changed over.

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