Really clever (or really stupid) technical question?

[bpm75]

For my HTPC set up the online calculators are quoting a PSU of around 900W. Now my primary concern for my HTPC is noise so........

If I buy a much higher rated PSU (ie 1000, 1200W, etc) so that it never reaches full load, will it be quiter than buying a 900W unit that will occasionally reach full load???

 

[Silverion77]

wth is in ur HTPC that needs 900watts?!?!

I dont even know gaming PCs that require that much....
Can u please post ur specs?

 

[bpm75]

Case : Zalman HD160XT Plus
CPU : Intel i7 940
MB : Asus P6T6 WS Revolution
RAM : Triple Channel 6GB OCZ Gold
5.25" : Blu Ray Writer
3.5" : 4 * Western Digital Black 7.2k 1TB
2.5" : 1* Western Digital Velociraptor 10k 300GB
Graphics : Radeon HD 4870 1GB
TV Card : Haupaugge HVR 4000 Quad Tuner
Wireless : D Link Wireless N Extreme
Cooling : 3* 80mm Silenx IXPs, 1* 92mm Silenx IXP, Acousipack Ultimate,
CPU Cool: Zalman CPS9900 LED
VGA Cool: Zalman GV1000

Hope this helps!

 

[Silverion77]

It does....

That PC needs nowhere near 900Watts...thats just ridiculous
U could really run that thing easily on a 600watt...750 would be comfortable
In terms of noise, just don't get a PSU with a small fan. Get one with a larger 120, 135 or 140 fan.
I highly suggest the Corsair TX 750, Seasonic M12D 750 (pretty expensive), or the new Antec Truepower "New" (weird name) 750 which showed to be a very competent Seasonic built PSU

But in terms of ur question....yes a larger PSU would be quieter do to lower loads and stress on the components

 

[bpm75]

I added it up to be about 600W but going online to these PSU calculators gave me my 900W figure, the 2 culprits being 200W to cover the HD 4870 graphics card and a staggering 500W to cover the quad core i7 chip!

So are ther any 135mm / 140mm fan sized PSUs at around the 750W marker that are particuarly known for their lack of noise?

 

[Silverion77]

500W for the i7 is just crazy....
What calculator are u using. Use the Outervision calculator (just google it). It generally over calculates to accommodate lousy PSUs.

From the reviews ive read, the New Antec isnt the quietest
I'm sure ud be fine with the Corsair 750

 

[cjl]

To repeat what I have said in the other thread, my entire computer uses 550-600W full load. I have measured this. With a power meter. From the wall.

I have an i7 @ 4GHz, a 4870x2, 3 hard drives (incl. 2 velociraptors), 12 gigs of RAM, a bunch of add in cards (x-fi, dual tuner TV card, wifi card, etc), and it still only uses 550-600W full load. Unless you're telling me that a 4870x2, 3 hard drives, 12 gigs of RAM, a motherboard, an x-fi, a dual tuner card, and more all can be run on 50-100W full load, the i7 won't even take anywhere close to 500W when overclocked. This also makes sense with the idle to load differential on the processor - the difference in power between running prime95 and complete idle is about 190W, indicating that the CPU needs around 190 watts full load at 4GHz. Note that the Intel thermal design power of the CPU is only 130W. Why would it ever use 4 times the TDP?

 

[bpm75]

In that case I know that 600W is enough! may still go for a 750 so I never reach full load (and therefore full noise!)

Thanks for the help guys! When I reach my next blank spot I know where to come! Just need to find A 750W PSU now that runs at 30db or less at about 75% loading.

 

[geofelt]

900w is wrong, you must have must entered wrong data into the calculator.

A normal system with a 4870 needs 500w and two pci-e 6 pin connectors.
http://ati.amd.com/products/Radeonhd4800/requirements.html
Add a small bit more for 5 hard drives.

A psu operates most efficiently in the middle of it's range, and will be quieter there also, so a bit more wattage than you need is not bad.
For a discussion of quiet computing and some quiet pc recommendations go to www.silentpcreview.com .
http://www.silentpcreview.com/article699-page1.html

You will see a number of qualiity psu's from seasonic, and corsair there.
The antec signature might be a good bet:
http://www.silentpcreview.com/Antec_Signature_650

You might get the 920 instead, with a mild overclock it will be like a 965 and cost half as much.

 

[cjl]

The Corsair 750W is pretty quiet, IIRC. I know my Corsair HX1000 is quieter than everything else in the computer at all load levels.

 

[bpm75]

Actually you are spot on! I was just on the calculator re doing it! I entered Quad socket under the first header thinking it was quad core. Schoolboy error. D'oh!

If people agree I should buy a higher than necessary wattage, to minimise noise by keeping it at lower loadings. Any suggestions for super quiet ones? Ive been looking at these combo heatsink / fan types where the fan only kicks in after a certain temp.

 

[cjl]

Quad socket i7?

Yeah, that changes things a bit...

What new wattage is it recommending, now that you have that corrected? Somewhere in the neighborhood of 400-500W or so?

I'd still recommend Corsair. Excellent PSUs, and I've had great success with them.

 

[Silverion77]

heh, just a bit...

They are coming with dual sockets soon though
At least what i saw from Cebit...
but yea, grab the Corsair. Large fan, quiet, reliable

 

[bpm75]

What do you think to the heat pipe combination ones from Dark Power and Zalman?

 

[Silverion77]

Dark Power = not reliable

Zalman is fairly good from what ive seen

 

[bpm75]

Excellent, I was looking at the zalmans anyway, they have the standard HP series then an XT series. Im making the assumption that the XT is better but looking at the specs the 750HP and 770XT are almost identical. The XT is a touch more efficient but uses less rails and obviously pushes out 20 more watts!

Anything else I should be looking out for?

 

[Silverion77]

I mean there havent been many reviews on the Zalmans like the Corsairs, but the few (like 1 or 2) i saw were pretty good.

I dont kno what OEM they use, so i don't even have a general idea on their quality

 

[rock1987]

I have the Corsair TX750W. Its a great PSU. Has a 140mm yate fan and is virtually silent.

 

[bpm75]

Doing more psu research, to minimise noise I wanted to try a heatsink / heatpipe fan combo but needed a really silent fan. The zalman has good reviews but no noise data. The Xilence XP600-FL is only rated at 12db for half load and 25db for full load. Then the cooler master silent pro has 17.5db for half load and 19db for full load which sounds almost too good to be true!

Im now more concerned that manufacturers are quoting these amazing figures by reducing fan speeds at the expense of cooling power anf cfm output! Therefore lowering my computers performance by increasing my operating temperatures!

 

[cjl]

Honestly, the Corsair PSUs are very nearly silent, especially at partial load. I'd just get a Corsair 750 and not worry about it any further than that.

 

[Silverion77]

^^exactly

Who cares what ratings manufactures put out? Not like that number is real under actual conditions....
Imo, Xilence and CM do not make "good" Psus like Corsair and others like Seasonic, Antec etc.

 

[bpm75]

Think Ill stick with that then, Ive been reading reviews for fans under the same principle of lowest db figures. The lower it goes the worse the fan review and the less people say its true! Antec seem to make some good case fans and corsair seem to do good everything, so i thik Ill stick with some well known and established brands!