Grinder said:
It just seems crazy to me that you're thinking about soldering on your
video card. With Paul I might pop some popcorn and pull up a chair, but
for you and I, an ambulance to should probably be summoned if we're to
seen making these sorts of plans.
What leads you to believe that you need to put more juice into this card?
A few crazy thoughts start to bounce around my head, when a question
like this comes up. I don't think there is any cause for concern, but
you should at least be aware of the background info for future reference.
*******
( This link should give you "Electromechanical_Updates.pdf" - see page 9 )
http://www.pcisig.com/developers/ma...c_id=fa4ec3357012d69821baa0856011c665ac770768
From page 9...
* The +12V delivered from the standard x16 edge
connector and the additional +12V(s) delivered via the
dedicated 2x3 and/or 2x4 auxiliary power connector(s)
must be treated as coming from independent separate
system power supply rails.
* The different +12V input potentials from different
connectors must not be electrically shorted at any point
on a PCI Express 225W/300W add-in card.
* The power pins of a single 2x3 or 2x4 auxiliary power
connector can be shorted together.
* No specific power sequencing between the slot, 2x3 and
2x4 connector power can be assumed. A PCI Express
225W/300W add-in card must handle all possible
combinations.
Now, while that references high power card design issues, the
same rules apply to lower power cards, with respect to the
various power inputs.
What those rules are intended to support, is an ATX power supply
with multiple rails, which are truly independent of one another.
Such a power supply might have separate transformers for 12V1,
and two more rails intended for PCI Express #1 and #2.
Now, a lot of modern supplies, don't work that way. On a regular
low end 12V1/12V2 supply, all the video card power comes from 12V1,
so soldering extra 12V1 wires from say a disk drive connector, won't
hurt anything.
Similarly, on some of the nice, unified rail supplies ("12V @ 52A")
type supplies, they have one giant transformer feeding 12V1, 12V2, 12V3
and so on. If 12V1 powered the slot, 12V3 happened to power a 2x3,
then again, no harm done.
You'd need a more obscure situation, where you had one of those
longish supplies with a bunch of independent transformers inside,
then 12V1 feeds the slot, and soldering a connection from 12V3 to
the auxiliary connector, you'd have to think about it.
Ok, now let's think about the video card end. To meet the four
bullets in that Powerpoint slide above, you need to plan the
video card switching regulators, so that they meet the requirement.
Let's say, for example, that I'm building a regular 9800 GT, not
the ECO version. In that case, I solder the 2x3 in place. The
regulators are likely to look like this.
12V1_from_slot -------- Vreg #1 ----- GPU_Core_voltage
PCIE_2x3 -------------- Vreg #2 ----- Memory chips perhaps
Now, if you forget to plug in the 2x3, the card would have logic
to check Power_Good from the regulators, before it would do anything.
Now, let's build the Zotac ECO version. We use the PCB from the
regular card, and decide to not solder in the 2x3. What do we need ?
A strap wire, running between regulators. (I looked, and I can't find
something like that in pictures.)
12V1_from_slot ---+---- Vreg #1 ----- GPU_Core_voltage
|
PCIE_2x3 --/ +---- Vreg #2 ----- Memory chips perhaps
Now, John comes along, and wants to solder a wire in place on his ECO.
12V1_from_slot ---+---- Vreg #1 ----- GPU_Core_voltage
|
PCIE_2x3 ---------+---- Vreg #2 ----- Memory chips perhaps
Now, strictly speaking, we've violated bullet points (1) and (2)
in the Powerpoint slide. But that is only important, if we have
a supply with truly independent output rails.
If John's supply has a unified output, or the supply is a smaller
one with 12V1 and 12V2, and all video card power is coming from 12V1,
that shorting strap is a non-issue.
In this case, I think it's safe to do, as John's supply likely isn't
one of those truly independent supplies from five years ago.
But in general, you'd better think pretty carefully, about where
the power is coming from, and what kind of power supply you've got,
before doing it.
In this case, a person would typically consider adding extra power,
if overclocking their ECO. For example, the regular 9800 GT in this
article, draws 83 watts max (it also has a 2x3 connector). If you
managed to boost the ECO version, it might manage to pass the 75 watt
limit of the slot. Normally, when they design video cards, they're
pretty conservative. To do what they did on that Zotac, normally
the engineer would limit card consumption to 48 watts (12V @ ~4amps),
so they don't usually push all the way to 75 watts. That card must
use considerably less power, than the MSI video card in this article.
http://www.xbitlabs.com/images/video/msi-9800gt/msi9800gt_power.gif
*******
With my power supply (a lower end one), I think it would be
safe to solder 12V and GND wires to that connector, since all my
peripheral power (motherboard and disk drive connectors), comes
from 12V1.
I'd probably take an ohmmeter, and buzz from the 2x3 12V pins, to the
12V pins on the PCI Express connector. They should be shorted in this
case, by whatever Zotac is using for a strap wire. To get a pinout for
PCI Express, use the Tomshardware picture. This will show you where the
12V pins are on the slot.
http://media.bestofmicro.com/A/L/101469/original/pcie-slot-big.gif
If the 12V pins on the video card slot connector aren't shorted to the
12V pins on the 2x3 connector pattern, then there is no point soldering
wires to it! There could be a de-populated strap somewhere else on the
card, separating the connector. It would only be worth soldering
wires to it, if it was bolstering the slot connector pins. So the
2x3 pattern should be common with the PCI Express slot contacts.
And then, soldering the wires, would make a difference.
If I thought you could buy a proper connector, I wouldn't even have
mentioned soldering wires. I don't know where I'd look, to buy one.
Radio Shack won't have one
Maybe you could chop up some kind
of cable assembly, but do they make PCIE to PCIE adapter cables ?
(That would give you a source of male and female connectors.)
They make Molex to PCIE, but that would be the wrong sex. You
could also just fit a 1x4 Molex to it, as long as you
bridged the three 12V pins to the 12V wire, and bridged the
rhree GND pins to the GND wire. I repaired my old ATI video card
with Molex connector on it, by soldering half of a Molex cable
assembly to it (the connector burned, and that's how I fixed it).
You buy a 1x4 Molex "Y" cable, to get both male and female
connectors plus wire. They're handy for hacks like this.
Molex ------- +12V --------------> to the three 12V pins
------- GND ----+---------> to the three GND pins
------- GND ----+
------- +5V
Paul
