Advice needed on PSU

P

Porky Josling

I've short-listed a number of items that will go into a new computer
but unsure about the PSU. Used a number of on-line calculators with
mixed results varying between 380W to 750W, my own gut feeling is to
purchase either a "Antec TruePower New TP-550" or a Thermaltake TR2 RX
Cable Management (W0134) 550W.

Items for new computer are;
CPU: Intel core i7-920 2.66 GHZ 8mb Cache Quad Core 2000 MHZ Socket B
(LGA1366).
Motherboard: Asus P6T SE.
Memory: Consair XMS3 Triple Channel Kit 3x2GB. Two kits making a total
of 12GB.
Video card: Gigabyte GV N96TSL-1GI - Graphics adapter - GF 9600 GT -
PCI Express 2.0 x16 - 1 GB GDDR3
Case: Lancool K58 with (4) fans.
Harddrives: (2)Seagate Barracuda 7200.12 - Hard drive - 1 TB
Monitor: 26" Wide Screen (minimum).
DVD Drives (2) Sata
Fan Controller.
Card reader.
Flash cards.
Keyboard and Mouse.
As well as the above there would be a number of USB items (printers +
scanner + external HD's + cable modem + speakers all of which have
their own power supply.

Any advice, or comments, in regards the PSU wattage would be most
welcome. The purchase price of the PSU is not too important but I
don't wish to waste money:)
 
P

Porky Josling

Though the 550 watt supply will probably be just fine...
there's never any harm in buying a supply larger than your actual needs.

BTW: with that much RAM I assume you are planning on going with a 64 bit OS
Click to expand...

Yes, Windows 7 64-bit. I have no problem in purchasing a larger PSU if
needed, and maybe it would be better to err on the safe side and go to
a 650W or even 750W, it's just as i mentioned before I don't wish to
waste money if not needed.
 
P

Paul

Porky said:
Yes, Windows 7 64-bit. I have no problem in purchasing a larger PSU if
needed, and maybe it would be better to err on the safe side and go to
a 650W or even 750W, it's just as i mentioned before I don't wish to
waste money if not needed.
Click to expand...

i7-920, TDP 130W, (130W/0.90) / 12V = 12.03 amps from 12V2 (assumes 90% eff Vcore)

9600GT (roughly 60W/12V = 5 amps from 12V1)

http://www.xbitlabs.com/articles/video/display/gainward-bliss9600gt-512gs_7.html#sect0

Hard drive 12V @ 0.6A each, 1.2A total
DVD drive 12V @ 1.5A each, when media present and spinning.
Fans 12V @ 0.5A estimated

Total 12V2 = 12.03 amps
Total 12V1 = 5+1.2+(1.5? + 1.5?)+0.5 = 9.7 amps with both DVDs loaded

Total power = (12V rails) + motherboard&ram + HDD_+5 + ODD_+5 + +5VSB_load
= 12 * (12.03+9.7) + 50W + 2*5W + 2*7.5W + 10W = 346W

So you want a power supply with enough amps on 12V1 and 12V2,
and an overall power rating of 350W or more. It's not likely
you'd be gaming, running Prime95, and copying DVDs all at the
same time, but I suppose it could happen :) That is what that worst
case calculation is assuming.

I recommend a minimum of 3.3V @ 20A and 5.0V @ 20A, mainly because
it isn't possible to compute values for those rails, and those
are likely safe minimum values. That helps cover the 50W to
run the motherboard chipset (includes 2W per DIMM), and a few watts for
various peripheral chips like Ethernet.

The TruePower New 550W has 45A max spread over all 12V rails, and 20A
max per rail, so the 12V is covered. It also meets the recommended min
for 3.3V and 5V. 3.3V and 5V combined are limited to 140W, and you
aren't likely to reach that limit. The above calculation suggests
about 75W loading combined for the two rails.

http://www.antec.com/Believe_it/product.php?Type=MQ==&id=MTc1OA==

According to this, the TruePower New is made by Seasonic under contract.
With Antec, they can change their source at any time (because they
buy units from others and don't make their own stuff).

http://whirlpool.net.au/wiki/?tag=PSU_Manufacturers

Paul
 
P

Porky Josling

i7-920, TDP 130W, (130W/0.90) / 12V = 12.03 amps from 12V2 (assumes 90% eff Vcore)

9600GT (roughly 60W/12V = 5 amps from 12V1)

http://www.xbitlabs.com/articles/video/display/gainward-bliss9600gt-512gs_7.html#sect0

Hard drive 12V @ 0.6A each, 1.2A total
DVD drive 12V @ 1.5A each, when media present and spinning.
Fans 12V @ 0.5A estimated

Total 12V2 = 12.03 amps
Total 12V1 = 5+1.2+(1.5? + 1.5?)+0.5 = 9.7 amps with both DVDs loaded

Total power = (12V rails) + motherboard&ram + HDD_+5 + ODD_+5 + +5VSB_load
= 12 * (12.03+9.7) + 50W + 2*5W + 2*7.5W + 10W = 346W

So you want a power supply with enough amps on 12V1 and 12V2,
and an overall power rating of 350W or more. It's not likely
you'd be gaming, running Prime95, and copying DVDs all at the
same time, but I suppose it could happen :) That is what that worst
case calculation is assuming.

I recommend a minimum of 3.3V @ 20A and 5.0V @ 20A, mainly because
it isn't possible to compute values for those rails, and those
are likely safe minimum values. That helps cover the 50W to
run the motherboard chipset (includes 2W per DIMM), and a few watts for
various peripheral chips like Ethernet.

The TruePower New 550W has 45A max spread over all 12V rails, and 20A
max per rail, so the 12V is covered. It also meets the recommended min
for 3.3V and 5V. 3.3V and 5V combined are limited to 140W, and you
aren't likely to reach that limit. The above calculation suggests
about 75W loading combined for the two rails.

http://www.antec.com/Believe_it/product.php?Type=MQ==&id=MTc1OA==

According to this, the TruePower New is made by Seasonic under contract.
With Antec, they can change their source at any time (because they
buy units from others and don't make their own stuff).

http://whirlpool.net.au/wiki/?tag=PSU_Manufacturers

Paul
Click to expand...

Wow, this will take awhile to penetrate the old noggin but just the
type of information I wanted, thanks.
Now, just to push my luck a little further, could/would you recommend
a PSU (make and model)that you feel would be suitable for me.
 
P

Paul

Porky said:
Wow, this will take awhile to penetrate the old noggin but just the
type of information I wanted, thanks.
Now, just to push my luck a little further, could/would you recommend
a PSU (make and model)that you feel would be suitable for me.
Click to expand...

You can use the reviews on Newegg.

http://www.newegg.com/Product/Produ...rk=False&ActiveSearchResult=True&Order=RATING

To be statistically significant, there should be enough reviews, so
that nobody can "ballot box stuff". What you're looking for, is
reviews where there are lots of DOA units or units where the
supply only lasts a few months.

Paul
 

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