SLI and power suppliy

Larry Stone wrote:
I have an 8800GTX and plan to add another. How critical is the power supply.
What happens if the PS is insufficient? The certified PS's at slizone all
cost at least $150.


WHY ON GOD'S GOOD EARTH WOULD SOMEONE SPEND 550+ DOLLARS FOR A VIDEO
CARD AND TALK ABOUT ADDING ANOTHER ONE AND COMPLAIN ABOUT A $150 POWER
SUPPLY. THE CHEAP POWER SUPPLIES THAT PEOPLE BUY ARE THE CAUSE OF AT
LEAST 60% OF THE OF THE "MYSTERIOUS" PROBLEMS THAT ARE REPORTED ON THIS
AND OTHER SITES. IF YOU ARE SERIOUS ABOUT TWO OF THESE CARDS I WOULD
CONSIDER LOOKING AT SOME OF THE POWER SUPPLIES IN THE 1 KW RANGE.

'Paul' wrote:
| While I don't have a reference that lists the exact part number for the
| PCI Express 2x3 power connector, pictures of it do suggest it is a member
| of the Mini-Fit Jr. family. Mini-Fit Jr. is used for a lot of the ATX
power
| connectors. The pins on Mini-Fit Jr. are rated to carry more than 4 amps,
| and the details are in a table here. Which raises the question as to why
| the 8800GTX has two 2x3 power connectors.
_____

Thanks for the additional information. I looked at the web page you cited,
and I agree that the 'Mini-fit Junior' looks to be what is used rather than
the Molex line that includes connectors like those used for ATA Parallel
drives (those connectors can't accept wires larger than 18 gauge, while the
'Mini-fit Junior' can accept 16 gauge). Like the 'Mini-fit Junior', the
8800 graphics board 6-pin power connectors have solid pins of smaller
diameter than the hollow pins on the Molex connectors used for ATA Parallel
hard drives,

I don't think the two 2X3 pin connectors for the 8800 GTX boards are to
annoy us, but a case of the reference board designer (nVidia) covering its
ass. If nVidia set the bar really high for power supply capacity and for
pin count, then there is somewhat less of a chance that marginal power
supplies will cause problems, manufacturing standards can be relaxed, and
improperly plugged cables will be less of a problem. Sort of like Intel
making CPUs that, with decent cooling, can be overclocked by a large
percentage. Intel builds in the extra margin to take care of minor quality
control problems and marginal system resources like power and cooling.

Also, look at the durability for the 'Mini-fit Junior'; 30 plug/unplug
cycles! I just got in the parts to build a system for overclocking Core 2
Duo CPUs; I'll probable go through 30 cycles in the first week! Extra pins
are going to extend the practical limit through redundancy. If a few pins
no longer mate well the others take up the slack.

I don't play games that need intense 3D acceleration and am more interested
in CPU/memory overclocking so my new overclocking system parts include just
one 8800 GTS.

I like the power consumption report xBit Labs wrote up a few years back.
It's time for a new one. With the new ATX 12V rev 2.2 power supplies with
modular cables it should be fairly easy to measure the power consumption
through the graphics 6-pin power connections; just cut the + 12 VDC leads on
an extra modular cable and insert a low value resistor across the cut (say
0.005 Ohms rated at 5 Watts) and measure the voltage difference across the
resistor.

Phil Weldon

"Paul" wrote in message ...
| Phil Weldon wrote:
..
..
..
| Molex connectors are specified for up to 4 Amps per pin. The 6-pin
Molex
| connector is limited to 12 Amps ( three + 12 VDC pins and three
earth/ground
| pins).
..
..
..
|
| While I don't have a reference that lists the exact part number for the
| PCI Express 2x3 power connector, pictures of it do suggest it is a member
| of the Mini-Fit Jr. family. Mini-Fit Jr. is used for a lot of the ATX
power
| connectors. The pins on Mini-Fit Jr. are rated to carry more than 4 amps,
| and the details are in a table here. Which raises the question as to why
| the 8800GTX has two 2x3 power connectors. If it really does average around
| 12 amps total of consumption, then one 2x3 connector should be plenty.
Now, if
| current software and applications cannot drive 8800GTX to the wall, then
| maybe we haven't seen the worst of it yet. It would almost seem two
connectors
| were used, to impress us (or annoy us), rather than solve a real problem.
| I'm still waiting for Xbitlabs to get of their duff and do some
measurements.
| They are the only enthusiast web site to have a clue.
|
| http://www.molex.com/catalog/pdf/5566VW.PDF
|
| Paul
|
|
|
| "Andi Cole" wrote in message
| ...
| | My 8800GTX's requires two 6-pin PCI-e connectors each, that makes the
| | picture clear as to how much power is required. I'm using an Etassis
850
| | which has four 6-pin connectors so no need for the adapters. I really
| | wouldn't skimp on the PSU.
| |
| | Andi.
| |
| |
| |
| |
| | "Larry Stone" wrote in message
| | newsZsQh.28585$oV.8460@attbi_s21...
| | I have an 8800GTX and plan to add another. How critical is the power
| | supply. What happens if the PS is insufficient? The certified PS's at
| | slizone all cost at least $150.
| |
| |
| |
|
|

'DaveW' wrote:
| Running TWO 8800 GTX cards in a computer requires a massive, expensive
PSU.
| They are not kidding. If you choose to use an economical lower power
rated
| PSU you can plan on burning out your cards due to low voltage.
_____

Please explain how "burning out your cards due to low voltage.' can happen.

Phil Weldon

"DaveW" wrote in message
. ..
| Running TWO 8800 GTX cards in a computer requires a massive, expensive
PSU.
| They are not kidding. If you choose to use an economical lower power
rated
| PSU you can plan on burning out your cards due to low voltage.
|
| --
|
| DaveW
|
| ___________
| "Larry Stone" wrote in message
| newsZsQh.28585$oV.8460@attbi_s21...
| I have an 8800GTX and plan to add another. How critical is the power
| supply. What happens if the PS is insufficient? The certified PS's at
| slizone all cost at least $150.
|
|
|

"DaveW" wrote in message

Running TWO 8800 GTX cards in a computer requires a massive,
expensive PSU.

Utter bull****. Any decent PSU with 40A or so on the 12v rails will cope
with SLI 8800GTX quite happily. It's been done.

"lkboop" wrote in message
...
Larry Stone wrote:
I have an 8800GTX and plan to add another. How critical is the power
supply. What happens if the PS is insufficient? The certified PS's at
slizone all cost at least $150.
WHY ON GOD'S GOOD EARTH WOULD SOMEONE SPEND 550+ DOLLARS FOR A VIDEO CARD
AND TALK ABOUT ADDING ANOTHER ONE AND COMPLAIN ABOUT A $150 POWER SUPPLY.
THE CHEAP POWER SUPPLIES THAT PEOPLE BUY ARE THE CAUSE OF AT LEAST 60% OF
THE OF THE "MYSTERIOUS" PROBLEMS THAT ARE REPORTED ON THIS AND OTHER
SITES. IF YOU ARE SERIOUS ABOUT TWO OF THESE CARDS I WOULD CONSIDER
LOOKING AT SOME OF THE POWER SUPPLIES IN THE 1 KW RANGE.

So sayeth the tech guru in caps lock.

Thanks to the group for the advice. My single 8800GTX runs fine with the no
name 550W PS that came with my case. I was pretty sure it would not be good
enough for the second card. I went to slizone.com and found a list of PS's
that are certified for two 8800GTX cards. I will buy one of them. What a
great thread!

"Larry Stone" wrote in message
newsZsQh.28585$oV.8460@attbi_s21...
I have an 8800GTX and plan to add another. How critical is the power
supply. What happens if the PS is insufficient? The certified PS's at
slizone all cost at least $150.

Larry Stone wrote:

Thanks to the group for the advice. My single 8800GTX runs fine with the no
name 550W PS that came with my case. I was pretty sure it would not be good
enough for the second card. I went to slizone.com and found a list of PS's
that are certified for two 8800GTX cards. I will buy one of them. What a
great thread!



What this thread has demonstrated is that the industry has failed to
produce meaningful yardsticks for the consumer as it relates to PSU's
and their applications, resulting in rampant misinformation even among
DIYers who are generally better informed.

Measuring a PSU's utility by Watts is as meaningless as measuring a
Vacuum cleaners suction power by Amps. Both are tangentially related to
the amount of 'work' they will be required to do.

The problem of amperage on rails is something that the industry has to
address, and a possible solution is to modify the packaging and
marketing materials to display what devices the PSU is meant to power.

SLI, RAID, a range of CPU's and memory configurations, even down to
specific models of video cards that a specific PSU is designed for. This
is what the consumer needs to know to make an informed purchase and
avoid costly returns which benefit no one.

'Mr.E Solved!' wrote, in part:
| What this thread has demonstrated is that the industry has failed to
| produce meaningful yardsticks for the consumer as it relates to PSU's
_____

It does nothing of the sort, and what you pose as a problem does not exist.
It is not the POWER SUPPLY specifications that need clarification, but
rather the DISPLAY ADAPTER specifications for power consumption. Read the
spec for ATX 12V rev 2.2; it is crystal clear.

Phil Weldon

"Mr.E Solved!" wrote in message
. ..
| Larry Stone wrote:
|
| Thanks to the group for the advice. My single 8800GTX runs fine with the
no
| name 550W PS that came with my case. I was pretty sure it would not be
good
| enough for the second card. I went to slizone.com and found a list of
PS's
| that are certified for two 8800GTX cards. I will buy one of them. What a
| great thread!
|
|
|
| What this thread has demonstrated is that the industry has failed to
| produce meaningful yardsticks for the consumer as it relates to PSU's
| and their applications, resulting in rampant misinformation even among
| DIYers who are generally better informed.
|
| Measuring a PSU's utility by Watts is as meaningless as measuring a
| Vacuum cleaners suction power by Amps. Both are tangentially related to
| the amount of 'work' they will be required to do.
|
| The problem of amperage on rails is something that the industry has to
| address, and a possible solution is to modify the packaging and
| marketing materials to display what devices the PSU is meant to power.
|
| SLI, RAID, a range of CPU's and memory configurations, even down to
| specific models of video cards that a specific PSU is designed for. This
| is what the consumer needs to know to make an informed purchase and
| avoid costly returns which benefit no one.
|

'Larry Stone' wrote:
| Thanks to the group for the advice. My single 8800GTX runs fine with the
no
| name 550W PS that came with my case. I was pretty sure it would not be
good
| enough for the second card. I went to slizone.com and found a list of PS's
| that are certified for two 8800GTX cards. I will buy one of them. What a
| great thread!
_____

Enjoy the results!

The Xbit Labs report on graphics card power consumption that 'Paul'
mentioned is at
http://www.xbitlabs.com/articles/vid...ption2006.html .

The report is now a year old, but the information is still valuable. I'd
expect Xbit Labs will soon post an update to include the 8800 series.

Phil Weldon

"Larry Stone" wrote in message
news:sQPQh.32675$oV.22865@attbi_s21...
| Thanks to the group for the advice. My single 8800GTX runs fine with the
no
| name 550W PS that came with my case. I was pretty sure it would not be
good
| enough for the second card. I went to slizone.com and found a list of PS's
| that are certified for two 8800GTX cards. I will buy one of them. What a
| great thread!
|
| "Larry Stone" wrote in message
| newsZsQh.28585$oV.8460@attbi_s21...
| I have an 8800GTX and plan to add another. How critical is the power
| supply. What happens if the PS is insufficient? The certified PS's at
| slizone all cost at least $150.
|
|
|

"Larry Stone" wrote in message
news:sQPQh.32675$oV.22865@attbi_s21
"Larry Stone" wrote in message
newsZsQh.28585$oV.8460@attbi_s21...
I have an 8800GTX and plan to add another. How critical is the power
supply. What happens if the PS is insufficient? The certified PS's at
slizone all cost at least $150.

Thanks to the group for the advice. My single 8800GTX runs fine with
the no name 550W PS that came with my case. I was pretty sure it
would not be good enough for the second card. I went to slizone.com
and found a list of PS's that are certified for two 8800GTX cards. I
will buy one of them. What a great thread!

What is your PSU's real 12v capacity? It may well have more than enough.