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Smallest possible PSU for a HTPC with a HD 5850

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March 27, 2010 3:26:24 PM

I am currently planning a new HTPC with enough graphics horsepower to take it to the occasional LAN party. This is not my main gaming PC, but it will have a lot of "up-time" because my family will use it as media center, for this reason low power draw would be good.

Currently my planned specs are:

CPU: Intel Core i3 530
Mainboard: MSI P55M-GD45
Memory: Mushkin Stiletto 2x2GB, DDR3-1333
GPU: cheapest available HD 5850 at the time of the actual purchase
Hard Drive: Intel SSD 80GB + whatever old SATA drive I have around (I can probably recycle an old 500GB drive)
Disc Drive: LG CH08LS, BluRay ROM
Case: Silverstone SST-GD05B Grandia Desktop

Now all I need is the PSU to go with that to give me just enough juice to run this rig on full load, but keep the power draw to a minimum. I do not need any reserves for OCing or future updates.

From calculating the power draw on http://extreme.outervision.com/psucalculatorlite.jsp I get a little over 300W. So I was thinking about the Seasonic S12II-380 (SS-380GB) Bronze - 380 Watt PSU as a conservative choice. I am wondering if I can get away with using the even smaller 330 Watt version of the same PSU.

The PSUs above only have one 6pin PCIe power connector - I read somewhere that you can get around that by using an adapter on a different power connector, is that accurate?

Has anyone tried to build a setup similar to this and has some experience to share? Any input would be appreciated.

Cheers,
Illex

More about : smallest psu htpc 5850

a b ) Power supply
March 27, 2010 3:34:14 PM

380watts will not cut it the 5850 needs at least a 400watt PSU. On neweggs PSU calculator they say a recommended PSU of at least 450watts for your setup but I would go for a 500watt.

Now the 5850 is a little overkill for a HTPC setup If you went to a 5670 or a 5770 you could get away with using a 400 watt PSU.
a b ) Power supply
March 27, 2010 3:49:07 PM

This is a good reliable power supply with all the connectors you need.
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Currently $40 after MIR so why not? With MIR I got the 600W a few months ago. Overkill for my system but cheaper than most of the power supplies that were the minimum I needed.

I assume of course that it is money you are worried about and not power draw from the wall. I am assuming you know that the computer will only draw as much power as it needs and that a power supply is most efficient when about 60% of the max load is being drawn from it.

A 5805 will draw a maximum of 170W off the +12V rails. When buying, you need to make sure that the power supply has at least 300W combined output on the +12V rails. You can find this out from the manufacturer. That's to be safe. You might be able to scrape by with 270W. Note this is the total draw on the +12V rails only.
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a b ) Power supply
March 27, 2010 3:52:32 PM



a b ) Power supply
March 27, 2010 3:53:25 PM

saaiello said:


Now the 5850 is a little overkill for a HTPC setup If you went to a 5670 or a 5770 you could get away with using a 400 watt PSU.


+1 to that suggestion. Go for a slightly less powerful card but one that has better efficiency and requires less power. You don't need a top-end card to output in full 1080HD really so that card would still be overkill.
a c 248 ) Power supply
March 27, 2010 5:38:51 PM

Hmmm.... a combination home theater pc and LAN parties. Interesting combination.

HTPC's do not require much in the way of a video card or power supply. The ATI Radeon HD 4770 would have been an appropriate choice. LAN parties are another matter.

Here are the official ATI Radeon™ HD5850 System Requirements:

PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard

500 Watt or greater power supply with two 75 watt, 6-pin, PCI Express® power connectors.

The recommendation is for an entire pc system. That does not mean the power supply will always be drawing 500 watts. The pc will only draw as much power as the system requires. If you are in HTPC mode doing something that only requires the power supply to draw 100 watts from the wall outlet (mains), then that is all the psu will draw. It will not draw the full 500 watts. Power consumption for a typical gaming session averages somewhere around 300 watts or less for a system with one video card. That is just an average. However, there may be sudden power spikes of very brief duration during "intense" scenes in a game. It appears they occur when going from a near idle state to high power state. A power supply needs to be able to handle those sudden rapid surges in power.

I took a look at the specifications of the htpc case. It can accomodate an atx power supply up to 188mm (7.042 inches) in length which is very good.

Since the pc will be used primarily as a home theater pc I am going to make a recommendation that is overkill. HTPC systems should be as quiet as possible so I recommend the Seasonic X-650 Gold, 650 watt power supply which earned a gold certifcation for energy efficiency. It is silent during normal operation at lower loads which makes it ideal for home theater use. It's also more more than sufficient for LAN parties. In addition it is 100% modular so you only use the power cables you need. That would come in handy in a smaller pc case like yours. The unit comes with a 5 year warranty.

Here is a link to a very favorable technical review at Silent PC Review where the psu earned the Editor's Choice Award:

http://www.silentpcreview.com/Seasonic_X650

In addition here is a link to a competent technical review at jonnyguru.com. The psu earned perfect 10's for performance and functionality.

http://www.jonnyguru.com/modules.php?name=NDReviews&op=...

I just happen to have the X-650 in my newest system and can attest to it's silent operation at lower loads. The fan doesn't kick in unless the temperature climbs at high loads. It is a new design that combines passive and active cooling.
a b ) Power supply
March 27, 2010 5:49:32 PM

but then again a smaller power supply does not mean lower power consumption your psu could be 400 watts or 1500 watts if your pc needs 225 watts it wil get 225 watts from either one what you really need is a mid range(500-650) power supply that is very efficient between 30-50% capacity
a b ) Power supply
March 27, 2010 6:02:08 PM

5850 power requierement: 500 Watt or greater power supply with two 75W 6-pin PCI Express® power connectors recommended (600 Watt and four 6-pin connectors for ATI CrossFireXTM technology in dual mode).

Therefore, If you want the smallest one, this is my suggestion: ANTEC EARTHWATTS 500W.
This PSU has been made by SEASONIC. It's very quite, good price and gives you power enough.

a c 243 ) Power supply
March 27, 2010 6:38:41 PM

Henry Chinaski said:

This PSU has been made by SEASONIC.

"has been" being the key part of that statement.
They've been made by Delta for around 2 years.
a b ) Power supply
March 27, 2010 6:43:15 PM

delluser1 said:
"has been" being the key part of that statement.
They've been made by Delta for around 2 years.


That is not correct. You are speaking about the 500D . The 500 is from Seasonic .
a c 243 ) Power supply
March 27, 2010 6:45:46 PM

Illex said:
So I was thinking about the Seasonic S12II-380 (SS-380GB) .

The PSUs above only have one 6pin PCIe power connector - I read somewhere that you can get around that by using an adapter on a different power connector, is that accurate?

Not that I don't think that the 380 couldn't handle it, but for $10 more you can get a 430 watt model , that has both of the required 6 pin connectors

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
a c 243 ) Power supply
March 27, 2010 6:48:26 PM

Henry Chinaski said:
That is not correct. You are speaking about the 500D . The 500 is from Seasonic .


The EA500 that you can get from Newegg or off the shelf at Staples ( If they haven't all been cleared out yet ) is the 500D, as I stated Delta took over manufacture of the Antec EA500 almost 2 years ago.
a b ) Power supply
March 27, 2010 7:04:04 PM

There are two different models:

ANTEC EARTHWATTS EA 500 - EC: It's from Seasonic and you can buy it (I have bought a new one six months ago... and it's from Seasonic)

http://www.hardwaresecrets.com/article/526

ANTEC EARTHWATTS EA 500D Green - EC. That one is from Delta.

http://www.antec.com/Believe_it/product.php?Family=MTE=

Those are the EARTHWATTS models from Delta:

380D, 430D, 500D, 650 and 750

Delta is manufacturing the CP (850/1000) and the SIGNATURE (650/850) series too.

The truepower (550, 650, 750) and the EARTHWATTS ( 380, 430 and 500) series are from SEASONIC.

FSP manufactures the QUATTRO (850/1000/1200) and the BASIC series.
a c 243 ) Power supply
March 27, 2010 7:11:23 PM

If you got a Seasonic built EA500 6 months ago, you got lucky.
And thanks, but I already know the oems.
a b ) Power supply
March 27, 2010 7:13:33 PM

You are wellcome.
a b ) Power supply
March 27, 2010 7:18:25 PM

It's a joke...

We just have different information. Maybe you are right, but I think that what I'm saying is correct.
a b ) Power supply
March 27, 2010 7:22:11 PM

Henry Chinaski said:
There are two different models:

ANTEC EARTHWATTS EA 500 - EC: It's from Seasonic and you can buy it (I have bought a new one six months ago... and it's from Seasonic)

http://www.hardwaresecrets.com/article/526

ANTEC EARTHWATTS EA 500D Green - EC. That one is from Delta.

http://www.antec.com/Believe_it/product.php?Family=MTE=

Those are the EARTHWATTS models from Delta:

380D, 430D, 500D, 650 and 750

Delta is manufacturing the CP (850/1000) and the SIGNATURE (650/850) series too.

The truepower (550, 650, 750) and the EARTHWATTS ( 380, 430 and 500) series are from SEASONIC.

FSP manufactures the QUATTRO (850/1000/1200) and the BASIC series.

the basic 550 is a delta
actually the true power's are from CWT
the true power trio are from seasonic
the quattro's are from enhance
a b ) Power supply
March 27, 2010 7:24:30 PM

About the quattro ones you are right. I'm sorry. I wrote it wrong.
a b ) Power supply
March 27, 2010 7:50:13 PM

ignore, delete won't work
a b ) Power supply
March 27, 2010 7:51:09 PM

sorry the true power 2.0 are from CWT
a b ) Power supply
March 27, 2010 10:27:38 PM

Get a 5770 and a Corsair CX400
a c 140 ) Power supply
March 27, 2010 11:32:04 PM

If you are not going to OC, SilentPCreviews "Recommended List and a 9.0 at jonnyguru will do you just fine. I'd grab an EA-650 or EA-500

For comparison purposes , the list of 650 watters below contains performance ratings (10 scale) at jonnyguru.com / prices as per newegg on 02/26/2010 and ones w/ double asteris (**) made it onto silentpcreview.com's Editor's Choice List:

Note: Just because you see a brand name on this list, never make the assumption that their other lines are of matching quality. Silverstone for example has other models w/ 6.0 and 7.0 ratings.

Antec Signature 650W (10.0) OOS **
Seasonic X-650 650W (10.0) $160 **
Silverstone Olympia OP650 (10.0) NFS

Thermaltake Toughpower QFan 650W (9.5) NLA

Antec Earthwatts EA650 650W (9.0) $75

Antec True Power Trio 650W (7.5) NLA

XFX XPS 650W XXX Edition Power Supply (7.0) NFS

Antec NeoPower Blue 650W (6.5) NLA

BFG BFGR650PSU 650W (6.0) NLA

NorthQ Black Magic Flex 650W PSU (5.0) NFS

NFS - Not For Sale / NLA = No Longer Available / OOS - Out of Stock


March 28, 2010 7:22:45 AM

Thank you for all the answers.

My aim is to keep the power draw low without compromising gaming power too much. Certainly one concern is to safe money, but also trying to be at least a little bit "green" ;) 

I did read the minimum requirements from ATI, but in all the reviews of the 5850 I read the total system power draw was much less than that (300W or less). Adding to that, all reviews where done with much more power hungry CPUs than the one I intend on using.

Now I don't know about the power spikes mentioned by JohnnyLucky... does anyone have information on how much headroom in terms of power you would need to deal with this?

As to the rather smallish PSU I suggested: According to the "80 plus" specification the highest efficiency of the PSU is around 50% load. So I'm looking to use a PSU that fits this as close as possible for my system on low load (i.e. watching movies, internet surfing) - where it will spend to most time running!

The relatively few hours this system will spend on full system load should be possible, but are not the main point in picking the PSU. I am considering using a smaller GPU, but as I remain a gamer at heart that would be a painful ;) 
March 28, 2010 8:21:28 AM

Thanks for the input obsidian86 but I don't fully agree with you.

380W should be more than sufficient for full load - barring any power spikes

The low load / idle power draw of the system I can only estimate, but I would guess that it should be well below 200W (according to most reviews around 150W, but once again they use much bigger CPUs).

If I use a 550W PSU and estimate a 150W power draw I'm using less than 30% of the available power and will spend most of the operating hours in a bad efficiency range. If I go with the 380W I get much closer to a 50% use of the PSU while having enough power available to run the 5850 on full load if required.

On the other hand, I agree with you because you suggested a "80 plus silver" PSU. Here the efficiency at 20% is the same as the "80 plus bronze" one at 50% load that I had planned on using. So while I think 550 is overkill, by going up one category to a silver certified PSU more than makes up for it - this I hadn't actually considered up to now.

... now if only I could find a gold certified PSU at 380W ;) 
a b ) Power supply
March 28, 2010 8:25:42 AM

lowest gold rated is 600 watts

lowest platinum rated is 4000 watts
March 28, 2010 9:27:23 AM

I had already considered the new Enermax Pro-87+ at 500W which is also gold rated... if it just wasn't so damn expensive
March 28, 2010 10:12:24 AM

AS far as I can tell only one person on here has made the correct suggestion....

+1 to obsidian86

The power draw from the wall is essentailly the same regardles sof the size of the power supply.

What I do know is that the harder you push a powersupply to its max, the more likely it is to fail, and I bet the cost of a new mb, proc and 5850 is much more than the few %s you'll save on a more efficient supply.
March 28, 2010 10:38:45 AM

will_chellam said:
AS far as I can tell only one person on here has made the correct suggestion....

+1 to obsidian86

The power draw from the wall is essentailly the same regardles sof the size of the power supply.

What I do know is that the harder you push a powersupply to its max, the more likely it is to fail, and I bet the cost of a new mb, proc and 5850 is much more than the few %s you'll save on a more efficient supply.



This is what this whole thread boils down to for me: How much power can I save by using the appropriate PSU for the job? The difference in efficiency at varying loads is exactly what's interesting to me.

Just slapping in any 600W+ PSU is the boring (but safe) solution ;) 

With a quality PSU (Seasonic, Enermax etc.) I really don't expect it to fail just because of a few hours operating near full load. As I mentioned, my load profile will be stacked quite heavily to low load operation.
a b ) Power supply
March 28, 2010 11:21:14 AM

Illex said:
This is what this whole thread boils down to for me: How much power can I save by using the appropriate PSU for the job? The difference in efficiency at varying loads is exactly what's interesting to me.

Just slapping in any 600W+ PSU is the boring (but safe) solution ;) 

With a quality PSU (Seasonic, Enermax etc.) I really don't expect it to fail just because of a few hours operating near full load. As I mentioned, my load profile will be stacked quite heavily to low load operation.


you will save virtually nothing by getting a perfectly sized psu... psu's are most efficient between perhaps 50% and 80% of capacity, pushing up to 90% and the cooling system for the psu will get more stressed and generate greater losses, spin up the fan more (which uses power), and perhaps fail. PSU's fail quickly at full load, its not a case of 10hrs at full load is ok, but 20 is not, it'll go quickly.

I'll repeat what someone else has said, to within a few % the power at the wall is the same regardless of the psu size, and to give you a clue as to the cost, that few % will cost you maybe 10 watts per hour, so for every 100 hours that the pc is on at load you'll use an extra unit of power. You'd be far far better choosing a low power cpu and a lower powered gpu, and focusing on the mobo to choose a low power one, and low voiltage memory, fewer case fans, green HDD's. Perhaps ensuring that your tv is green, or perhaps not having a htpc, but using a dvd player hdd recorder which with less operating system overhead will be a lot cheaper to buy and run.

done some sums, at 10W extra losses due to a mis sized supply, at 5c per unit of electricity, on 24x7, will save you $4.60 per year. Is that worth the risk of killing your system, or the extra noise (in fact a 5w fan spinning at full as opposed to a near passive cooling would cost you another $2.30) so getting a bigger supply would probably only cost you $2.30. all at 5c/kwh multiply up the costs are more.
March 28, 2010 1:16:13 PM

13thmonkey said:
you will save virtually nothing by getting a perfectly sized psu... psu's are most efficient between perhaps 50% and 80% of capacity, pushing up to 90% and the cooling system for the psu will get more stressed and generate greater losses, spin up the fan more (which uses power), and perhaps fail. PSU's fail quickly at full load, its not a case of 10hrs at full load is ok, but 20 is not, it'll go quickly.

I'll repeat what someone else has said, to within a few % the power at the wall is the same regardless of the psu size, and to give you a clue as to the cost, that few % will cost you maybe 10 watts per hour, so for every 100 hours that the pc is on at load you'll use an extra unit of power. You'd be far far better choosing a low power cpu and a lower powered gpu, and focusing on the mobo to choose a low power one, and low voiltage memory, fewer case fans, green HDD's. Perhaps ensuring that your tv is green, or perhaps not having a htpc, but using a dvd player hdd recorder which with less operating system overhead will be a lot cheaper to buy and run.

done some sums, at 10W extra losses due to a mis sized supply, at 5c per unit of electricity, on 24x7, will save you $4.60 per year. Is that worth the risk of killing your system, or the extra noise (in fact a 5w fan spinning at full as opposed to a near passive cooling would cost you another $2.30) so getting a bigger supply would probably only cost you $2.30. all at 5c/kwh multiply up the costs are more.


Thank you for the example. I'm sure you're right about the potential savings - btw I live in Switzerland where the cost of electricity is around 4x that what you suggested... still, that won't make a huge difference.

As for the PSU, I think I will actually go with a gold rated one that's bigger than what I need. The efficiency of that operating at 20% load will still be quite a bit higher than the bronze rated Seasonic at 50% I was initially set on using.

So even thought I will be operating the PSU in a less ideal load profile it will still safe me power. Once smaller gold/silver rated PSUs (~400W) become available I might buy a new one and reuse the bigger one in a desktop PC.

a b ) Power supply
March 28, 2010 2:23:15 PM

wait for geil thortech power supplies
a c 248 ) Power supply
March 28, 2010 2:58:32 PM

Geil Thortech looks interesting - gold certified ony.
March 29, 2010 3:05:09 PM

I bit the (prize) bullet and ordered the new Enermax Pro-87+ 500W (gold certified).

Thank you all for your input!

Cheers,
Illex
!