GTX 690 in MacPro4,1 with no external PSU

[5050]

Looks like the setup would sync the external PSU with the MP's PSU although it could be a mess to route the cables. Unless you have plans to use your external PSU to power two GTX 690's, what I don't understand is why didn't you choose the booster X5 like most others did? It is more compact and can be easily installed in the second ODD bay, and has a built-in molex plug to sync with the main PSU.

I had initially considered this internal PSU, but having read dozens of threads on getting the GTX 690/Titan to work on their Mac Pro's, more users just seemed to advocate the use of an external PSU, especially a high-quality one. One of the most important considerations was that I couldn't come up with a decent solution to run the power cord from the Booster X5 (i.e. from the optical bay) out of the MacPro4,1 enclosure. Lastly, the GTX 690 being a 300W card, I thought would have the option to power an additional GTX 690 in the future if I decided to scale into another one (although please correct me if I'm wrong here that 660W is enough to power two GTX 690s).

Have you used the Booster X5 successfully with any cards?

 

[5050]

From a quick google search, it looks like the GTX 690 requires:
38 Amps on the +12v Rail
TDP: 300 Watts

38amps x 12Volts = 460Watts, yet the card has a TDP of 300watts.

If you go by Amperage you need a PSU that has 76 Amps on the +12v Rail (912 Watts on +12v Rail)

If you go by Wattage\TDP you need a PSU with 600 Watts on the +12v Rail
(50 Amps on the +12v Rail)

Very Confusing

Actually, I forgot about this response I got back from EVGA:

Hello, The TDP for the card would be 300w but the actually power usage of the card would be higher. I would recommend something along the lines of 400w and above. If you have any further questions or concerns please feel free to let us know. Regards, EVGA Technical Support

 

[Tesselator]

A couple of things.

1) once you know what pins to jump you can make it more permanent and safer (than the stupid paper-clip way) just by using a little ingenuity. Like, instead of going into the front of the connector you can enter thru the rear. You can use a piece of shielded solid core electrical wire like they use to wire a house. You can also remove the pins in question, strip the ends, and solder and/or twist them together and then shield them with electrical tape. The adaptors you linked to below look like they would work too, yes. The system function of those two pins is typically a push-on/off switch that shorts those two pins and thus starts the power up. It's a little more complicated but that's basically it.

2) Do not try to supply the 75W thru the 6-pin connector (to the GPU card) by using a SATA power connector which is rated at about one third of what you need. I can't remember if the SATA power is rated at 20W or 40W but it's NOT 75W so don't do it. It may even work for a year or something but you will be running your system very inappropriately and overdrawing thru/from some components not made or rated to support that. Those SATA Power to Molex Power adaptors are made for drives that don't happen to have a SATA power connector. I dunno of any drives that draw more than about 20W - peak - and typically it's about half that. You could probably run a fan or something but no way would I connect it up to the GPU in any way for the supply of power.

Can either of these adaptors be used to "jump two PSUs" using "one" MacPro4,1 motherboard?

http://cablesaurus.com/Dual-PSU-24-Pin-Adapter-Cable
http://www.amazon.com/Phobya-2-Way-...sr=8-6&keywords=Dual+PSU+24-Pin+Adapter+Cable

Also, where would I locate the 24-pin Connector on the MacPro4,1? Had a look inside the case and can't seem to locate it . . .

Yeah, as others have mentioned it doesn't actually connect to the Mac. There will be a bunch or connectors that will be left hanging like that. All you will need to use is the 6/8 pin connectors. The 6-pin is designed to supply 75W and the 8-pin is designed for 150W.

The GTX 690 (typically) is a 300W card. So you probably have two connectors; one 6-pin and one 8-pin. The Card Slot supplies 75W too so it probably looks like:

One 6-pin: 75W
One 8-pin: 150W
Card Edge: 75W
--------------------
Total pwr: 300W

And if it were me I would supply both the 6-pin and the 8-pin to such a card from your auxiliary PSU. If the card is two 8-pin connectors you have to supply both from the aux PSU.

You probably already know most of that but I thought I might reiterate a little.

 

[5050]

A couple of things.

1) once you know what pins to jump you can make it more permanent and safer (than the stupid paper-clip way) just by using a little ingenuity. Like, instead of going into the front of the connector you can enter thru the rear. You can use a piece of shielded solid core electrical wire like they use to wire a house. You can also remove the pins in question, strip the ends, and solder and/or twist them together and then shield them with electrical tape. The adaptors you linked to below look like they would work too, yes. The system function of those two pins is typically a push-on/off switch that shorts those two pins and thus starts the power up. It's a little more complicated but that's basically it.

2) Do not try to supply the 75W thru the 6-pin connector (to the GPU card) by using a SATA power connector which is rated at about one third of what you need. I can't remember if the SATA power is rated at 20W or 40W but it's NOT 75W so don't do it. It may even work for a year or something but you will be running your system very inappropriately and overdrawing thru/from some components not made or rated to support that. Those SATA Power to Molex Power adaptors are made for drives that don't happen to have a SATA power connector. I dunno of any drives that draw more than about 20W - peak - and typically it's about half that. You could probably run a fan or something but no way would I connect it up to the GPU in any way for the supply of power.




Yeah, as others have mentioned it doesn't actually connect to the Mac. There will be a bunch or connectors that will be left hanging like that. All you will need to use is the 6/8 pin connectors. The 6-pin is designed to supply 75W and the 8-pin is designed for 150W.

The GTX 690 (typically) is a 300W card. So you probably have two connectors; one 6-pin and one 8-pin. The Card Slot supplies 75W too so it probably looks like:

One 6-pin: 75W
One 8-pin: 150W
Card Edge: 75W
--------------------
Total pwr: 300W

And if it were me I would supply both the 6-pin and the 8-pin to such a card from your auxiliary PSU. If the card is two 8-pin connectors you have to supply both from the aux PSU.

You probably already know most of that but I thought I might reiterate a little.

Hi Tesselator, thanks for your reply. Never intended to use the SATA 15-pin power connector to power the GTX 690, but to use in conjunction with the external PSU to make it "power aware" so that it can power up and down in sync with the internal MacPro4,1 PSU. See my post today (April 28) at 5:09 PM . . .

Seem viable?

 

[Tesselator]

Hi Tesselator, thanks for your reply. Never intended to use the SATA 15-pin power connector to power the GTX 690, but to use in conjunction with the external PSU to make it "power aware" so that it can power up and down in sync with the internal MacPro4,1 PSU. See my post today (April 28) at 5:09 PM . . .

Ya, I know. I was offering a word of caution as I have seen people who decided to try it that way.

Seem viable?

It's probably OK. I've never looked into it myself so I dunno exactly. I wouldn't do that myself tho. For one it gobbles up a SATA bay and I use them all. For another I dunno the power-up timing sequence well enough to know if it's going to power up the GPU too late and therefor surge the MP PSU every time I cold-start or even restart. For yet another reason I dunno what is being connected to what in order to simulate that push-on switch I mention previously.

I personally would investigate how the Mac is doing it and then piggy-back the aux PSU onto that system. But I haven't looked into that either so I dunno what's involved. I assume it would be a few solder connections or some line splicing.

I remember skimming a post (I think it was here) some time ago where the guy did just that and spliced the aux PSU into the Mac's system. I'll try to find it and link ya up if you're interested.

 

[Tesselator]

Ah, here's what I read:

http://latewire.com/MacProPSU
​

But that uses a SATA connector as well so I wouldn't go about it in the same way as this either. I'd find out what jumps the MP PSU and piggyback onto that if possible.

 

[handheldgames]

Don't forget there is another power tap at the front of the motherboard that feeds the optical bay.

 

[5050]

Ah, here's what I read:

YouTube: video
http://latewire.com/MacProPSU
​

But that uses a SATA connector as well so I wouldn't go about it in the same way as this either. I'd find out what jumps the MP PSU and piggyback onto that if possible.

Thanks for the vid above. I think I started to read this guy's thread last week but was COMPLETELY intimidated by all the custom wiring and soldering. Kudos to you if you have the experience to pull this off!

 

[5050]

It's probably OK. I've never looked into it myself so I dunno exactly. I wouldn't do that myself tho. For one it gobbles up a SATA bay and I use them all. For another I dunno the power-up timing sequence well enough to know if it's going to power up the GPU too late and therefor surge the MP PSU every time I cold-start or even restart. For yet another reason I dunno what is being connected to what in order to simulate that push-on switch I mention previously.

I personally would investigate how the Mac is doing it and then piggy-back the aux PSU onto that system. But I haven't looked into that either so I dunno what's involved. I assume it would be a few solder connections or some line splicing.

Found this thread. Nanofrog has a great breakdown of how to set this up using the Add2Psu.

https://forums.macrumors.com/threads/1290225/

 

[TheEasterBunny]

I've not done this build, but I have done many other applications similar to this.
Personally, I would use a 12V molex on the Mac PSU to power a relay. Placing the relay inside the Aux. PSU.
The power for a relay is negligible, so it could be just a tap.
This way when the Mac PSU powers up, it powers the relay, which turns on the Aux. PSU.
All this should post before the MB even has power, so at boot the card would be fully powered.
I also would clip all unnecessary wires and cap them with shrink tube, but do this INSIDE the Aux. PSU, this prevents cabling running all over the place, potentially affecting cooling.
Just my .02