Application to estimate PSU needs?

littlebigman · Post by **littlebigman** » Fri Sep 03, 2010 4:07 am

Hello

I was wondering if someone knew of an application that would combine those two into a single Windows application...

1. www.piriform.com/speccy to get the list of hardware items that make up a PC
2. www.thermaltake.outervision.com/Power to estimate how much power is actually required to run the PC

... ?

Thank you.

littlebigman · Post by **littlebigman** » Fri Sep 03, 2010 4:15 am

For instance, for the following basic desktop, Thermaltake says that I should get a 240W PSU:

Operating System : MS Windows XP Professional 32-bit SP3

CPU : AMD Athlon 64 X2 5200+ 65 Â°C : Brisbane 65nm Technology

RAM : 2.0GB Single-Channel DDR2 @ 387MHz (6-6-6-18)

Motherboard : ASUSTeK Computer INC. M2N68-AM Plus (AM2)

Graphics : 19'' @ 1024x768 : 128MB GeForce 7025 / NVIDIA nForce 630a (ASUStek Computer Inc)

Hard Drives :
195GB Seagate ST3200822A (ATA) 44 Â°C
488GB Western Digital WDC WD50 00AAKS-00WWP SCSI Disk Device (IDE)

Optical Drives : HL-DT-ST DVD-RAM GH22NS30 SCSI CdRom Device

Audio : Realtek High Definition Audio

So I guess a 120W PicoPSU is out of the question?

quest_for_silence · Post by **quest_for_silence** » Fri Sep 03, 2010 4:34 am

littlebigman wrote:So I guess a 120W PicoPSU is out of the question?

It might even suffice but, if in case, barely: give a look (for a comparison purpose) there.

Regards,
Luca

littlebigman · Post by **littlebigman** » Fri Sep 03, 2010 4:47 am

quest_for_silence wrote:http://www.silentpcreview.com/article778-page4.html

Thanks for the tip. The test gives 87W top but only includes a single hard-drive and no optical drive, so I guess 120W should be OK for my setup.

I have two further questions:
1. Why does the Thermaltake applet recommend 240W, then?
2. How can I compute the requirements for the external part, ie. the power brick? Should I get a 80W/12V ie. about 7A?

ilovejedd · Post by **ilovejedd** » Fri Sep 03, 2010 5:01 am

littlebigman wrote:1. Why does the Thermaltake applet recommend 240W, then?

When I tried it with your parts, I got:
Minimum PSU Wattage: 138W
Recommended PSU Wattage: 188W

By the way, this one's more up to date than the link you're using:
http://extreme.outervision.com/

littlebigman wrote:2. How can I compute the requirements for the external part, ie. the power brick? Should I get a 80W/12V ie. about 7A?

I wouldn't. The system SPCR tested already consumes 87W. Granted, that's AC power but your CPU is a higher TDP part so it's possible you might exceed 80W under load. I recommend going with a 100W or higher brick to be safe.

quest_for_silence · Post by **quest_for_silence** » Fri Sep 03, 2010 5:19 am

littlebigman wrote:1. Why does the Thermaltake applet recommend 240W, then?

The Outervision app is widely used and widely overestimate the needs: the more, the better, they sue.
However, we say: 65W for the cpu, 40W for the drives at startup, 20W for ram and optical, 30W for the IGP under stress, and eventually 20W for the rest of motherboard lead to about 175W DC, still far from 240W.

littlebigman wrote:2. How can I compute the requirements for the external part, ie. the power brick? Should I get a 80W/12V ie. about 7A?

Afaik a simple trick could be your power requirement plus some room, if in case, in order to be safe.

Another simple choice could be the bigger you can afford to have some room to grow in the future.

My choice could be the Dell DA-2, which is also one of the favourites among SPCR readers (more probaby that not, it's not suitable for the PW-200).

Regards,
Luca

littlebigman · Post by **littlebigman** » Fri Sep 03, 2010 5:22 am

Thanks for the tip. I got a recommended 216W:

System Type: 1 physical CPU
Motherboard: Regular - Desktop
CPU: AMD Athlon 64 X2 5200+ 2600 MHz AM2 Windsor
CPU Utilization (TDP): 90% TDP
RAM: 1 Stick DDR2 SDRAM
IDE HDD 7200 rpm: 1 HDD
Regular SATA: 1 HDD
DVD-RW/DVD+RW Drive: 1 Drive
Keyboard and mouse: Yes
System Load: 90 %

Recommended Wattage: 216 Watts

ilovejedd wrote:I recommend going with a 100W or higher brick to be safe.

Thanks for the info. I admit I'm a bit confused as to why PicoPSU says a 120W model is OK, eXtrem Outversion says it's over 200W, and a 100W+ power brick is recommended. I never groked electricity

littlebigman · Post by **littlebigman** » Fri Sep 03, 2010 7:24 am

A picture being worth a thousand words...

http://img37.imageshack.us/img37/8082/psuchoice.png

I don't understand how a 100W brick can power a 120W PicoPSU which in turn can power a modest, two-HD AMD desktop that uses about 200W

lm · Post by lm » Fri Sep 03, 2010 7:42 am

Look, it's all really simple: rated max power for the brick must be larger than power drawn from it and same goes for the Pico part. However those calculators just don't give the correct numbers.

Do this: build your system using an old temporary psu that you maybe have lying around or borrow or whatever.

Then measure the true Max power while running cpuburn for all cores and furmark. Power meters are cheap so buy or borrow.

Now those numbers have some extra that is because of the inefficiency of the psu you used but since the Pico must have some headroom you can pretty much just use that number as is.

littlebigman · Post by **littlebigman** » Fri Sep 03, 2010 7:51 am

lm wrote:Look, it's all really simple: rated max power for the brick must be larger than power drawn from it and same goes for the Pico part. However those calculators just don't give the correct numbers.

In that case, if the PC components use 175W, the 120W PicoPSU clearly isn't enough, and the 100W power brick even less.

I'll find a power meter and use a standard PSU to check how much juice the thing uses.

Thank you.