imported_Dmitheon

Junior Member
Jan 7, 2005
4
0
0
Can any one recommend a PSU guide? I'm in the process of building a machine, and after doing a fair amount of research on a quality PSU, I find it may not be enough. Simple watt ratings don't seem to be enough and I don't know what else I need to keep in mind. It does help that manfacturers seem to be changing their recommendations either. Case in point: eVGA's 7800GT has a recommendation of 450Watt, where as in various reviews the recommendation is 350Watt.
 

JEDIYoda

Lifer
Jul 13, 2005
33,986
3,321
126
OKIA 650 watt PSU!!!

Dual Quad 12 rails!!

Yes thats right count them-- dual Quad equals 8 -- 12 volt rails!!!

OKIA the name legends are made from!!!
 

GalvanizedYankee

Diamond Member
Oct 27, 2003
6,986
0
0
For a start go to www.tomshardware.com and half way down the page you will find PCs and How To.

They full load test 19 PSUs for 6 weeks, noise at idle and full load is also noted.

My needs are met with a FSP400-60PFN, its under rated as it tests at 435watts. I'm only up-grading to
a 6800 at present. This unit had a very loud fan and because I have more than enough intake air into
the case, I changed out the PSU fan for a quieter one.

For what FSP offers the price point is very good. FSP also offers Fortron w/o the FSP in the name.
Many consider the FSP superior. There are better PSUs but not at the price imho.
The more efficient a PSU is the less waste heat it generates and can get by with a quieter fan.
The FSP Group Inc. is near the top in efficiency.
EDIT#2 The above unit has PFC and can be had new at Newegg for $59. Whatever you get, shop around.

jj


EDIT: Welcome to Anandtech. Your very first post. Glad to have you aboard enjoy your stay.

Be sure and click on guides at the top of our site and go to FAQ. Andy does a good job of
keeping it current. Lots of good non-fanboy info there.
 

Zepper

Elite Member
May 1, 2001
18,998
0
0
Welcome to the AT Forums.

One doesn't need to fret so much over the choice of a PSU. We know from empirical data that most systems actually use 250W or less from their PSUs. So a QUALITY 350-400W PSU is adequate for most systems (even high-end ones) as long as the power is properly proportioned among the rails for them. Having 20-25 Amps available on the +12V rail(s) (I prefer and recommend single rail over split rail for flexibility) should be adequate for systems that run their CPUs off the +12 rail (use the P4-12V connector for CPU power). After that, it's just a matter of selecting a reliable brand. And that has been rehashed here and elsewhere ad nauseam.. Suffice to say that if you are spending much less than $50. for a new 350W PSU, the you are likely not getting a good one. One can often get good buys in used and/or refurbished PSUs.
. The feature called "active PFC (Power Factor Correction)" is a good one to look for as it is generally only found in a given brand's higher line products. aPFC usually comes in tandem with another feature, full-range voltage compensation, that can tolerate from ~100 - ~240VAC at ~50-60Hz. This also makes your system fairly immune to a lot of AC line side garbage thus yielding a more stable system. These features are well worth their cost, IMO.

.bh.
 

Bona Fide

Banned
Jun 21, 2005
1,901
0
0
Sorry to hijack this thread, but I've seen several of those "Wattage Calculators". Does anyone have any of those on hand?
 

KoolDrew

Lifer
Jun 30, 2004
10,226
7
81
Originally posted by: Bona Fide
Sorry to hijack this thread, but I've seen several of those "Wattage Calculators". Does anyone have any of those on hand?

Here is one:
http://www.extreme.outervision.com/index.jsp

However I must note that just because that calculator says you may need a certain wattage PSU means very little. The fact is PSU specs mean very little. Some cannot supply what it is rated and some (Fortron) routinely exceed their specifications. The reality of the situation is that it is much more complex then just some intigers are going to indicate. You have to move to actual knowledge of the supply itself.
 

Operandi

Diamond Member
Oct 9, 1999
5,508
0
0
Originally posted by: Bona Fide
Sorry to hijack this thread, but I've seen several of those "Wattage Calculators". Does anyone have any of those on hand?

Those are not worth your time, horribly inaccurate.

To the OP Zepper has some good information there, I agree with all of it. The only thing will mention is dual 12v rails are now part of the ATX standard which means most/if not all quality future PSU's will be adhering to it.

For some further reading check out SPCR's Power Distribution within Six PCs to see how much power a typical PC really consumes and just how inaccurate those power calculators are. SPCR also has some of the best reviews around as far as proper testing, give them a read.
 

imported_Dmitheon

Junior Member
Jan 7, 2005
4
0
0
First off, thanks for all the welcomes. I find it kinda funny that I started reading this site back when Tom was THE authority and Sharky was still extreme. :)

Also, thanks for the Watt calculator.

Originally posted by: KoolDrew
What is the specs of your system?
My System:

MSI K8N SLI (not the platinum, just normal SLI),
AMD Athlon X2 3800
2x 512MB DDR memory (TWINX1024-4400C25 1GB Kit DDR550 XMS4400 Memory)
eVGA 7800GT
1HDD: Western Digital Caviar 250GB Serial ATA II 7200RPM w/16MB Buffer
1 DVD Rom Pioneer slot, don't recall number, it's left over from last machine.
1 Plextor CD-RW, don't recall number, it's left over from last machine.

My ordered PSU:
Seasonic S-12 430Watt power supply. I went with Seasonic because it's gotten alot of good reviews from the HTPC crowds for quality and being quiet, and ultimately when the sun sets on this machine, it'll get moved to HTPC. That was before I read the eVGA forums.

I'm not even looking for recommendations so much as find a real listing for system requirements. When it was just "Get enough Watts, and from a reputable manufacturer", that was fine. Now with things like recommended Amps on the 12V rail, and any other similarly subtle requirements that aren't typically found on the box of either the PSU or the video card itself, I think a reference guide would be useful.

I'm thinking about just going to a compusa or best buy and getting a well reviewed ~500watt psu as a back up incase the Seasonic fails.

 

imported_Dmitheon

Junior Member
Jan 7, 2005
4
0
0
Found this off of that Watt calculator

http://forums.extremeoverclocking.com/showthread.php?t=136602

I think this is what I was looking for.

I've seen a number of recommendations for around 25Amp on the +12V rail, unfortunately the Seasonic I ordered (and actually just showed up), is lacking that:

SeaSonic S12-430 ATX12V 430W
Type ATX12V
Maximum Power 430W
Fans 1
PFC Active
Dual +12V Yes
Efficiency Up to 80%
Input Voltage 100 - 240V
Input Frequency Range 50/60Hz
Output +3.3V@30A, +5V@30A, +12V1@14A, +12V2@15A, -12V@0.8A, +5VSB@2A
MTBF >100,000 Hours
Approvals UL, CE, DEMCO, NEMCO, SEMCO, FIMCO, CB, FCC, CCC

I'm guessing I don't get to add those to a nice 29, do I?
 

cronic

Golden Member
Jan 15, 2005
1,782
0
0
do yourself a favor and buy a pc power and cooling power supply. they are simply rock solid!
 

Operandi

Diamond Member
Oct 9, 1999
5,508
0
0
Originally posted by: Dmitheon
Found this off of that Watt calculator

http://forums.extremeoverclocking.com/showthread.php?t=136602

I think this is what I was looking for.

I've seen a number of recommendations for around 25Amp on the +12V rail, unfortunately the Seasonic I ordered (and actually just showed up), is lacking that:

SeaSonic S12-430 ATX12V 430W
Type ATX12V
Maximum Power 430W
Fans 1
PFC Active
Dual +12V Yes
Efficiency Up to 80%
Input Voltage 100 - 240V
Input Frequency Range 50/60Hz
Output +3.3V@30A, +5V@30A, +12V1@14A, +12V2@15A, -12V@0.8A, +5VSB@2A
MTBF >100,000 Hours
Approvals UL, CE, DEMCO, NEMCO, SEMCO, FIMCO, CB, FCC, CCC

I'm guessing I don't get to add those to a nice 29, do I?

I guess I?ll just repeat myself?. Try to listen this time.

Those power calculators are completely useless; don't waste your time with them. Read my first post look at the SPCR and you will see what a real systems draws, it's no where near what those calculators will tell you.

FYI, the Seasonic you purchased will be more then enough.
 

Zepper

Elite Member
May 1, 2001
18,998
0
0
The Seasonic has a total of 29A of +12V. Way more than you'll ever need, but the S12 series are excellent PSUs with all the good features: aPFC, full range voltage, etc.. They will eventually pay for themselves in power savings alone.

.bh.
 

JEDIYoda

Lifer
Jul 13, 2005
33,986
3,321
126
Originally posted by: KoolDrew
Originally posted by: Bona Fide
Sorry to hijack this thread, but I've seen several of those "Wattage Calculators". Does anyone have any of those on hand?

Here is one:
http://www.extreme.outervision.com/index.jsp

However I must note that just because that calculator says you may need a certain wattage PSU means very little. The fact is PSU specs mean very little. Some cannot supply what it is rated and some (Fortron) routinely exceed their specifications. The reality of the situation is that it is much more complex then just some intigers are going to indicate. You have to move to actual knowledge of the supply itself.

Sad another vieled plug for Fortron....rofl.......heheeeeee

Again as was stated by Zepper---

One doesn't need to fret so much over the choice of a PSU. We know from empirical data that most systems actually use 250W or less from their PSUs. So a QUALITY 350-400W PSU is adequate for most systems (even high-end ones) as long as the power is properly proportioned among the rails for them. Having 20-25 Amps available on the +12V rail(s) (I prefer and recommend single rail over split rail for flexibility) should be adequate for systems that run their CPUs off the +12 rail (use the P4-12V connector for CPU power). After that, it's just a matter of selecting a reliable brand. And that has been rehashed here and elsewhere ad nauseam.. Suffice to say that if you are spending much less than $50. for a new 350W PSU, the you are likely not getting a good one. One can often get good buys in used and/or refurbished PSUs.