Is my 600w PSU overkill for this system...??

PSUs: The source of DC power for all components in the PC & often a big noise source.

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kylo
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Is my 600w PSU overkill for this system...??

Post by kylo » Mon Sep 21, 2009 2:10 pm

i just got this system..
the PSU and Case where a Combo!!

Specs.............................................................................................
NEW SYSTEM- running windows XP pro 32bit
CPU - AMD Athlon II X2 245 Regor 2.9GHz 2 x 1MB L2 Cache Socket AM3 65W Dual-Core Processor -- running the cpu with the stock fan and HS
Memory - G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500)
MoBo - GIGABYTE GA-MA785GM-US2H AM3/AM2+/AM2 AMD 785G HDMI Micro ATX
HD - 500GB 7200 RPM 32MB Cache SATA
PSU - 600watt
Monitor - 20inch flatscreen
1x80mm case fan
1xDVD/RW drive
1xusb mouse and keyboard
also i am using headphones.. (so there are no speakers)

thats all that is running!!! i think its about 350ish watts??
I might add a 120mm fan later.. on and maybe PCI.E graphic's card...

So is it bad to only use 55% of the PSU??
Shouldn't less work make it last longer and its overall temp lower??
Last edited by kylo on Mon Sep 21, 2009 2:23 pm, edited 1 time in total.

kater
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Post by kater » Mon Sep 21, 2009 2:17 pm

Overkill? Naaaah ;)

I'd say you'd be perfectly fine with a 200W PSU, and have plenty of headroom for OC. If you add a discrete VGA then this will change, depending on the VGA.

650W is good enough for a v strong CF/SLI & i7 rig.

barefootzero
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Post by barefootzero » Mon Sep 21, 2009 2:31 pm

To give you a point of comparison...

With a 90W AC-DC brick and electrodacus's DC-DC adapter I am running the following.

CPU AMD Athlon II X2 240 w/stock HSF
Mem 2x2 GB DDR3
MB MSI 785GM-E65
HD 3.5" Seagate SATA 250GB 7200RPM drive (just about to replace this)
DD NEC IDE DVD-RW

With Prime95 running I reach about 65W. I think I might have seen the system peak into the 70W range once. The system Idles close to 40W. I still need to find out what programs to use to stress the HD, CPU, GPU, DVD all at the same time.

I hope that helps answers your question. 90W might be a little close for comfort for some people but the brick seems really over engineered. I think you would be fine with 100W easily. A 200W PSU would put your system idle right above the key 20% mark.

kylo
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Post by kylo » Mon Sep 21, 2009 2:52 pm

Sooo is having a 600w for this system going to be BAD (any negative effects on the system) or is it just really going to be underused...?

Slso how do u tell how much power your pc is currently drawing from the PSU? Are there programs that show this or do u just check the specs of the hardware and add it up?

tehfire
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Post by tehfire » Mon Sep 21, 2009 3:46 pm

You don't mention what brand it is...a good-quality 600W PS would definitely be overkill.

The only "bad" thing about using a higher-power PSU is that generally speaking, PSUs are not at their peak efficiency at low loads. It isn't very noticable, however, so I wouldn't worry about it too much.

There are a few good PSU calculators out there, but the best way to do it is to buy a wattmeter that you plug into the wall and plug the PSU into the wattmeter. The Kill-A-Watt is a very popular one, and is under $20.

kylo
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Post by kylo » Mon Sep 21, 2009 4:20 pm

Its a Rosewill.. is that a good or bad brand?
I mean it looks great and runs great!!!

MikeC
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Post by MikeC » Mon Sep 21, 2009 4:57 pm

barefootzero wrote:I still need to find out what programs to use to stress the HD, CPU, GPU, DVD all at the same time.
Why would you try to do such a thing? There's no real-life combination of applications that can possibly achieve this; totally unrealistic. Even just Prime95 + Furmark gives higher power demand than I've ever seen in real apps, which remains peaks in in 3D games. Even the most demanding 3D games don't give you steady-state high power like Prime95 + Furmark but vary up & down, and the peaks don't match P95+FM.

barefootzero
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Post by barefootzero » Mon Sep 21, 2009 5:20 pm

Much below 20% capacity it is normal for a normal PSU to be ~70% efficient. There are three factors here. Extra heat means extra noise from the CPU. Extra heat means your computer room might be a little warmer during the summer. Extra heat means extra dollars from the power company and during the summer that also includes pumping extra heat out of your house (wish I knew how to calculate that last one).

Concerning electricity cost. If your system only need 60W and your PSU is 70% efficient then you are burning on extra 25W that you don't have to. Depending on where you live and how much you leave your computer on this can add up. Between my wife and myself our media computer is on 12 hours a day at .15kW/hr (Tracy, Ca. price). So 10W extra costs us $6.57/year. You should measure your consumption then look up the cost per a kW/hour where you live and make a decision.

The only real way of telling how much energy your system is using at the outlet is measuring it with a Kill-a-Watt or similar power meter. I got a Seasonic Power Angel for $50 including shipping but at Fry's I saw a similar Kill-a-Watt for $20.


@MikeC
I just wanted to do it so when someone asked I could say my PC has xxx peak power consumption and this PSU is totally bullet proof.

I guess I can try future mark + prime95 instead.

barefootzero
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Post by barefootzero » Mon Sep 21, 2009 10:24 pm

Follow Up
Running Furmark + Prime 95 I got a maximum draw from the outlet of 88W. If the brick is 90% efficient then the system power would be 80W giving a head room of a little over 10% plus whatever factor of safety was engineered into the brick (I am guessing this is a good quality brick from previous experience with NEC and is therefore accurately labeled).

lm
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Post by lm » Fri Oct 02, 2009 5:29 am

Why can't anyone answer the OP's question?

Since you already have the PSU, there's absolutely no point to change it in this situation.

Even if some other PSU would be marginally more efficient at the PC's idle load, the cost of such a new PSU would not pay itself back in saved energy costs in the likely lifetime of the system.

Also, having a PSU that can handle high max power does not hinder the operation of the system in any way and does not reduce the lifetime of any part of the system.

The best reason to change the PSU would be if you actually perceived any non-imaginary problem on it, like it being too loud (which needs to be checked by temporarily stopping one fan at a time by gently pushing the eraser end of a pencil on the central hub of the fan so that the friction stops it).

mcoleg
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Post by mcoleg » Fri Oct 02, 2009 3:38 pm

OK, I'll answer the OP questions :P

"thats all that is running!!! i think its about 350ish watts??" - you are maxing at under 90W right now, if that, depending on how hot the system is.

"So is it bad to only use 55% of the PSU??" - it's from 10 to 15% that you are using. As long as the system boots, it's not bad at all (all other considerations except the operational one aside).

"Shouldn't less work make it last longer and its overall temp lower??" - no one cares, really. You are not going to use the same PSU for 10 years. It's simply a good excuse for people to buy bigger PSUs than they'll ever need. Ppl in the know save money or invest in better brands.

That brings us to the last bit - you haven't asked it but - for the next build get something better than Rosewill - there are plenty of recommendations around here for a good PSU.

As for now, unless it makes noise or something, just leave it be. If there's no defective parts in it, it should work just fine.

I hope this answers your questions :P

MikeC
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Post by MikeC » Fri Oct 02, 2009 9:23 pm

kylo wrote:Its a Rosewill.. is that a good or bad brand?
I mean it looks great and runs great!!!
Rosewill is Newegg's house brand. Made for them, or more likely, bought from some ODM's stock PSU lineup. Never seen, heard nor tested one, so no comment.

bendit
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Post by bendit » Wed Oct 07, 2009 5:57 pm

yes it's overkill. but you have it so why not use it? if you can sell it and want to start over, I would get an efficient 80+ 300w psu.

SebRad
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Post by SebRad » Thu Oct 08, 2009 1:42 am

Hi, as another data point I'm running an E6600 OC'd to 3GHz with GTX260 video card on Seasonic 330w PSU. Running heavy load of Folding@Home on the CPU and GPU gets up to ~240w from the wall which would be 200-210w DC load from the PSU.
Regards, Seb

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