Can I run SLI with 380W PSU?

I have an Antec Sonata with a 380W PSU, Asus A8N-SLI, AMD64 3500+. 1 gig
Corsair ram, 120 gig HDD, DVD drive and a Leadtek 6600GT.

I plan on adding another 6600GT. Is my PSU sufficient?

Ron

In article , Ron Joiner
wrote:

I have an Antec Sonata with a 380W PSU, Asus A8N-SLI, AMD64 3500+. 1 gig
Corsair ram, 120 gig HDD, DVD drive and a Leadtek 6600GT.

I plan on adding another 6600GT. Is my PSU sufficient?

Ron

Page 2-25 of the A8N-SLI Deluxe manual contains a Power Requirements
table. It says 12V @ 17A minimum on the output of the power supply,
for a pair of 6600GT. An Antec Truepower is 12V @ 18A, so it just
squeeks by. The Asus table says 350 watts total power minimum, and
the Truepower is 380 watts.

The 6600GT draws 4 amps from +12V:

http://www.xbitlabs.com/articles/vid...00gt-oc_3.html

Whether the 3500+ is enough to drive the two cards to max power
is a good question, so they might not make it all the way to
4 amps.

A quick power calc:

http://www.amdcompare.com and list Athlon64. Check the part number
for your processor and see if it is 67 watts or 89 watts. At
89 watts, your +12V current is 89/12 * 1/0.90 = 8.2 amps at
90% efficiency conversion by the Vcore circuit.

Processor 8.2 amps (less if it is the 67 watt processor)
Video 2x4.0 = 8.0 amps (CPU limited most of the time, so 8 amps)
Disk drive = 0.5 amps
Fans 1.0 amps (or compute the exact number using fan labels)
Total 17.7 amps

The reason I didn't include the DVD, is you aren't likely
to be burning at the same time as gaming. If just reading
a game CD, you might throw in another 0.5A for 12V. Good data
is not available for most optical drives.

Modify the above calculation as you see appropriate :-)

Paul

Paul wrote:
In article , Ron Joiner
wrote:


I have an Antec Sonata with a 380W PSU, Asus A8N-SLI, AMD64 3500+. 1 gig
Corsair ram, 120 gig HDD, DVD drive and a Leadtek 6600GT.

I plan on adding another 6600GT. Is my PSU sufficient?

Ron


Page 2-25 of the A8N-SLI Deluxe manual contains a Power Requirements
table. It says 12V @ 17A minimum on the output of the power supply,
for a pair of 6600GT. An Antec Truepower is 12V @ 18A, so it just
squeeks by. The Asus table says 350 watts total power minimum, and
the Truepower is 380 watts.

The 6600GT draws 4 amps from +12V:

http://www.xbitlabs.com/articles/vid...00gt-oc_3.html

Whether the 3500+ is enough to drive the two cards to max power
is a good question, so they might not make it all the way to
4 amps.

A quick power calc:

http://www.amdcompare.com and list Athlon64. Check the part number
for your processor and see if it is 67 watts or 89 watts. At
89 watts, your +12V current is 89/12 * 1/0.90 = 8.2 amps at
90% efficiency conversion by the Vcore circuit.

Processor 8.2 amps (less if it is the 67 watt processor)
Video 2x4.0 = 8.0 amps (CPU limited most of the time, so 8 amps)
Disk drive = 0.5 amps
Fans 1.0 amps (or compute the exact number using fan labels)
Total 17.7 amps

The reason I didn't include the DVD, is you aren't likely
to be burning at the same time as gaming. If just reading
a game CD, you might throw in another 0.5A for 12V. Good data
is not available for most optical drives.

Modify the above calculation as you see appropriate :-)

Paul
Very helpful Paul.

Ron

--
And it really doesn't matter if
I'm wrong I'm right
Where I belong I'm right
Where I belong.

Lennon & McCartney