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Quiet power supply for this build
Posted: Sun Sep 14, 2008 4:10 am
I came here a few months ago to ask this question but then put the build on hold until the HD X4870 X2 became available to the UK.
My build looks as follows:
Antec Solo case problably with replaced outtake fan
Core 2 Duo 3.33Ghz 45nm w/ HR-01 PLUS using 120mm duct to outtake fan
2x 4GB RAM
ATI HD 4870X2 - just starting to look into cooling for this
Asus Xonar DX
Measuring power draw is not my forte, and in the past I have simply lent towards overkill. I believe the Enermax Modu82+ 625W is popular here, but at that rating may be overkill for my needs. On the other hand I suspect that at the very least the GPU may be replaced two generations down the line, or if suddenly quad computing becomes a gaming must within four years then that also could be replaced.
So, should I stick with an Enermax Modu82+ 625W, or is there a better choice for my needs?
Posted: Sun Sep 14, 2008 5:03 am
There have been reports that the Enermax82+ isn't doing well with a 4870X2.
And even if copes with the high load (264W according to Xbitlabs) it would ramp up significantly.
Link to Xbitlabs article, page 6: http://www.xbitlabs.com/articles/video/ ... html#sect0
My advice would go for a PSU with 140 mm fan that keeps the rpm low upto 400W, like the Zalman 850W.
Link to SPCR review, page 4: http://www.silentpcreview.com/article834-page4.html
That PSU however is big and heavy, but the Coolermaster Silent Pro, also made by Enhance, entered the market.
BTW, do you realize that the 4870X2 won't fit in the Solo, unless you cut into the drive bay?
And if you'll be able to find an aftermarket cooler for the 4870X2, you'll dump all that heat into the case.
This would ruin your ducted setup for the CPU.
Posted: Sun Sep 14, 2008 5:52 am
I didn't know it didn't fit the Solo. That's... a pain.
Posted: Sun Sep 14, 2008 8:19 am
I've been steered towards the P182 as an alternative to the SOLO and as I'm someone looking to do minimal work on the case itself this looks like a good choice.
I looked at your PSU and certainly it looks to be a solid choice. I was surprised that, with the noise coming in as low as it does, that it isn't on the recommended PSU page. I love that it's putting so much power into the box but staying so damn quiet with absolutely no customisation, and the kind of head-room that means you don't need to understand power load.
There appear to be quite a few in the ZM #-HP range, do you know if they are all equivalent in terms of noise?
Another question would be whether the cables will be long enough to work with the P182's two-tier design?
I am not that knowledgeable on the workings of PSUs, if I have a kilowatt PSU does that mean it is permanently pulling that much power, or does it respond to system demand? In other words, ignoring up-front costs, would it cost more to run a more powerful power supply?
Posted: Sun Sep 14, 2008 9:59 am
A PSU outputs approximately the amount of power that your system draws plus some procent. The quality of the PSU determines how efficient it is.
For example, an 80+ certified PSU draws power from the wall equivalent to what the system needs + ~20%.
The efficiency of a PSU degrades the hotter it gets. Most PSU's are rated at a certain output at a certain temperature. The output of the PSU degrades significantly for every 10 degrees celsius the temperature rises in the PSU.
Posted: Sun Sep 14, 2008 10:26 am
OK, so really the rating represents maximum draw, while the effeciency is how much it will cost me to run over time. So an 80% efficient 750 power supply is cheaper to run than a 70% 650 PSU, approximately.
Posted: Sun Sep 14, 2008 10:48 am
Quitch wrote:OK, so really the rating represents maximum draw, while the effeciency is how much it will cost me to run over time. So an 80% efficient 750 power supply is cheaper to run than a 70% 650 PSU, approximately.
That sounds about right. An 80+ PSU are 80% efficient at almost any realistic load. A low quality non efficient PSU can fluctuate a lot all over the spectrum and will also degrade faster/get hotter.
Posted: Sun Sep 14, 2008 10:51 am
In that case I'll probably go with the ZM 750-HP, since I assume it should, pretty much, share the same characteristics as the ZM 1000-HP, while being cheaper and providing all the power I need.
Posted: Sun Sep 14, 2008 10:54 am
Quitch wrote:In that case I'll probably go with the ZM 750-HP, since I assume it should, pretty much, share the same characteristics as the ZM 1000-HP, while being cheaper and providing all the power I need.
note the ZM 750-HP is supposedly based on a different PCB from the 850 and 1000W versions. (see the review of the ZM-600 which was not very favourable). you're probably better off with something like a Corsair TX750.
Posted: Sun Sep 14, 2008 10:57 am
I thought the ZM-600 wasn't part of the HP range?
EDIT: My bad, it clearly is. I think I'll just play safe and invest the additional money in the 1000 then.