Looking for a PSU on a budget

D

dragoon38900

New Member
Ok, Ive been trying to figure out if my current COOLMAX CP-500T would be able to power my system:

CPU - Core 2 Duo 6600 Conroe 2.4GHz
MOBO - GIGABYTE GA-965P-DS3
RAM - CORSAIR XMS2 2GB (2 x 1GB) DDR2 800
VIDCARD - EVGA 8800GTS 320mb
HD - Western Digital Caviar 250GB 7200 ATA150
2 Case Fans
2 DVD Drives

And I finally concluded that NO it cannot. I even emailed COOLMAX about it and they said:

not enough, this video card will draw 21a by itself single or dual rail. Cp-500 is upto 29a, not enough to support your ram if its 2gb too .

I suggest the cw-650t minimum or ctg-700 and cug-700 max

You can wait till tomorrow or Friday sale with buy.com on our PSU
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Also, a person from Tomshardware forums said:

The CT line from Coolmax are not all that great. If you like coolmax then stick with there CTG line. I would not advise sticking with that PSU when you upgrade to the 8800.

Consider this. Your CPU is the only item that sits on that 1st +12v rail rated at 16A. While the rest of the system's items that needs 12v is on the 2nd rail rated at 18A. Now the 8800 alone will be using about 8A, motherboard pulls about 2, then each drive is pulling about 2A. We also want to add in 1A or 2A for every 2 fans you have in the system and that includes the CPU cooler. So already you are at about 16A with just the basics running under a heavy load. Add in the small power draw of a couple of extra HDDs, and other miscellaneous power being drawn from other items and you are seriously stressing that PSU. You could be looking at peak loads up around 20A to 22A. Granted that peak loads only last a split second but it's still pushing an otherwise mid quality PSU. You might see instability problems due to the PSU's heavy load.
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Now my problem is, I am in a budget. I have roughly $90 left in my account,
and I need to buy a new one (including the shipping...thats about a $10 shipping so, I only have $70-$80 to spend). Can anyone recommend me a budget PSU that will be able to run this system. If there is no such thing in that price range, I will need to refund the PSU, and I will only get about $30 back... so by then Ill have about $110 to spend. However, returning it will be my last resort.

Thank you.
 
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Would it be impossible to try to get 20 dollars from somewhere? Look in all your old pants/shirt pockets, look for coins in the house? lol. If you go a little higher than 80 dollars itd be a lot easier.
 
OK, let's put things in perspective here:
not enough, this video card will draw 21a by itself single or dual rail. Cp-500 is upto 29a, not enough to support your ram if its 2gb too .

I suggest the cw-650t minimum or ctg-700 and cug-700 max

You can wait till tomorrow or Friday sale with buy.com on our PSU
Click to expand...
I'm sorry, but whoever told you that hasn't got a clue what they're saying.
  • That video card cannot and will not draw 21A. That's almost twice what's permitted under the spec
  • 2x1GB of RAM will not draw more power than 2x512MB. RAM only draws a very small amount of power, all from the 3.3V rail. I suppose I could give him/her the benefit of the doubt and assume he/she is talking about avoiding a RAM bottleneck that would prevent the GPU from achieving its full performance and thus power consumption, but it's still not a strong argument.
  • That PSU is rated for [email protected], not 29A
  • A 650W+ PSU is certainly not required for a single video card system

Consider this. Your CPU is the only item that sits on that 1st +12v rail rated at 16A. While the rest of the system's items that needs 12v is on the 2nd rail rated at 18A. Now the 8800 alone will be using about 8A, motherboard pulls about 2, then each drive is pulling about 2A. We also want to add in 1A or 2A for every 2 fans you have in the system and that includes the CPU cooler. So already you are at about 16A with just the basics running under a heavy load. Add in the small power draw of a couple of extra HDDs, and other miscellaneous power being drawn from other items and you are seriously stressing that PSU. You could be looking at peak loads up around 20A to 22A. Granted that peak loads only last a split second but it's still pushing an otherwise mid quality PSU. You might see instability problems due to the PSU's heavy load.
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This argument has a little more merit, but those numbers aren't realistic. If that were the case it wouldn't be just that Coolmax that wouldn't run an 8800, but any compliant dual rail PSU. This is quite obviously not the case.

Now I'm not going to argue that the Coolmax is a great quality PSU, but it should be sufficient for your system. Keep in mind that the official recommendation for a system with an 8800GTS is only 400W with +12V@26A. If you do decide to replace the PSU, the Corsair is unbeatable at that price.
 
That video card cannot and will not draw 21A. That's almost twice what's permitted under the spec
2x1GB of RAM will not draw more power than 2x512MB. RAM only draws a very small amount of power, all from the 3.3V rail. I suppose I could give him/her the benefit of the doubt and assume he/she is talking about avoiding a RAM bottleneck that would prevent the GPU from achieving its full performance and thus power consumption, but it's still not a strong argument.
That PSU is rated for [email protected], not 29A
A 650W+ PSU is certainly not required for a single video card system
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Funnny thing is, I emailed them back about this before. I told him that he mixed up the CP-400t model with the CP-500t model. He replied to me saying:

You are right, sorry about that

Yes, this is sufficient enough


http://www.extreme.outervision.com/psucalculator.jsp
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It looks like he was using that psucalculator to determine everything, which is why he said 21A... Im not sure though.

I think I will do this: Try using the COOLMAX for now, and then if problems appear, I shall immediatly buy another one, most likely the Corsair or an Antec TruePower Trio 550W.
Question: What are the "symptoms" of insufficient power that I should watch out for? What are the ways of testing the power?
 
official recommendation for a system with an 8800GTS is only 400W with +12V@26A
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So my Antec EA380 could run it, it has 33V on the 2 12V rails?
Also, Thanks for the help Ceewi1, the Antec is running my new system fine :)

IF it wasn't enough you'd get random restarts.
 
EA380 is +12V@27A, you can't just add the rail numbers. It should run it, but is pushing it a little further than would be ideal.

Random restarts are the most common symptom. You can also occasionally have your GPU driver telling you that the GPUs are receiving insufficient power, and extremely rarely you'll just find a huge drop in framerates when gaming.

It's always worth keeping an eye on the voltages on each of the PSUs rails, particularly the +12V. If they're dropping towards or below the minimum permitted under spec (5% below their ideal figure, e.g. 11.4V for the +12V rail), it's a strong indication that the PSU is being very heavily worked.
 
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