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Less known- How 2 6pin works perfectly for GTX580 or HD5870 eyefinity

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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
153
As title, I don't think I have seen anywhere that used my way for GTX 580 or HD 5870 2gb working in mac pro. I have used it for 2 years, I felt guilty for not sharing with you folks. Here it is with photo.

It's easy and hassle free (for me at least) as long as you can find a copper wire ( size as shown, not too big not too small like people used to say it ), like making a spring. Plug it in the two holes make it contact both pins inside. That's it. Use your two 6 pins from mac pro. Don't be afraid, if you are not burning your mac pro with battlefield 3 for 24 hours a day. It's safe for you.

I used the card with tessellation benchmark software before, not a problem at all. (don't need to be a copper wire, any wire that can make good contact for the pins will do the same job)

Enjoy it!
 

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All Taken

macrumors 6502a
Dec 28, 2009
780
1
UK
Can you purchase an app called HW monitor and tell us how much power is being drawn via the 2x 6 pin?

You say Battlefield 3 24 hours a day isn't something you do, understandable but what do you run? An average work load in your day?

How many drives do you have in your system? PCIe cards?

Thanks
 
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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
153
No, I don't have that software to tell wattage consumed. You are right, I don't play that battlefield 3 game. What I use with my mac pro daily is premiere pro and after effects CS6, also playing VLC for blu-ray quality movies. I have only one blu-ray drive, two SSDs, one USB 3.0 pcie card only.

But using HD5870 eyefinity (2gb version) I played Unigine Heaven benchmark for mac pro without issue, if that can alleviate your concern.
 
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All Taken

macrumors 6502a
Dec 28, 2009
780
1
UK
Right so we're talking about a 250w max draw, can that benchmark produce that kind of load? 75w a piece on the 6 pin connectors and 75w from the PCIe slot is giving a 225w total. The reason this is working is either the total power consumption isn't getting above 225w or if it is the extra 25w is fairly easily covered by the 2x 6 pin connectors.

The reason I mention the above is that many of us want to know how much 'extra' load the tracers on the back plane board are capable of handling. Thanks for the info.
 
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goMac

Contributor
Apr 15, 2004
7,662
1,694
I'm no expert, but wiring a card's ground into itself doesn't seem like a bright idea.
 
ActionableMango

ActionableMango

macrumors G3
Sep 21, 2010
9,612
6,907
This appears to be doing the exact same thing that the 8-pin to 6-pin adapters do (jumping the two extra grounds).
 
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maxmaut

macrumors regular
Nov 13, 2011
134
4
I've seen this discussed before.
8-pin is there for some reason. It might work for 99 users, and then fail for one unlucky guy. MacVidCards had lots of posts about this.
I don't think that anyone who is using MP for work should take a risk like this.
 
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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
153
Ok, folks,

As some one already point out, this works same way as you purchase a 6to8 pins converter. So aren't you happy this can save you money for it? Also it's neater in your mac pro case.

In addition, I think most people if you are not heavy gamer, 99% of the time, your GPU is running half or even less of its capacity. If you know what a two years running safe (for me) mean to you, there is a way to try like this. For people who dare not, this is not your dish. So make your own judgement!
 
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ghislain

macrumors member
Apr 22, 2009
98
12
modern GPU

Depending on applications used, modern GPU like 5870 can run at full speed, medium speed or at low speed in the so-called low energy saving mode, as can be seen under bootcamp with GPU-Z. I guess that with 2 6pin connectors, GPU will always stay in the low energy saving mode...and low performance..Therefore, this may ennoying for applications that rely on heavy GPU load such as 3D games. Otherwise, it will probably works decently as stated above..
 
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All Taken

macrumors 6502a
Dec 28, 2009
780
1
UK
ghislain said:
Depending on applications used, modern GPU like 5870 can run at full speed, medium speed or at low speed in the so-called low energy saving mode, as can be seen under bootcamp with GPU-Z. I guess that with 2 6pin connectors, GPU will always stay in the low energy saving mode...and low performance..Therefore, this may ennoying for applications that rely on heavy GPU load such as 3D games. Otherwise, it will probably works decently as stated above..
Click to expand...

What is it you're trying to add to the discussion? The card is pulling 250w at most and the Mac Pro by design can deliver 225w. The extra 25w is being drawn via the 2x 6 pin at 12.5w per connection. The card is not 'aware' of the extra draw being made, it 'thinks' it has a 6pin and 8pin connected.

It is not in a 'crippled' state as you suggest above.
 
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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
153
The only time that GPU will draw 250w is when doing gaming along with max GPU fan speed. So even when I am doing Premiere Pro and After Effect CS6 rendering, which use higher GPU utilisation, it's not drawing full 250w at all. (It's still wont be reaching to the point like continues gaming). However, as I have used my HD5870 Eyefinity for the Heaven Unigine benchmark for couple of times before. I am pretty much confident to share with you guys.
 
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initialsBB

macrumors 6502a
Oct 18, 2010
688
2
Thanks Prince134 for the 8 pin ground jump trick ^^
I got a R9 280X and despite the seller assuring me the 6 to 8 adapter was included in the box, it wasn't... This got the card running while I wait for a real adapter I got on order, just to make it cleaner inside :p
 
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Asgorath

macrumors 68000
Mar 30, 2012
1,573
479
Ahh great, this discussion again. I'd encourage you to get HWSensors to track the power usage on your system, it's free and should give a lot of relevant information.

Couple points of clarification:

1) Shorting that connector is exactly what the 6-pin to 8-pin adapters and real 8-pin connectors do. All the power comes in on the other pins, so shorting this connection just signals to the GPU that it's safe to pull up to 150W on that connector.

2) The critical, unanswered question revolves around the traces on the motherboard that connect to the small 6-pin auxiliary power connectors. We're all sure that they've been engineered with some amount of tolerance, but whether that tolerance is literally more than double the expected power draw, I don't know.

3) The power won't be pulled evenly across both connectors in a 6-pin and 8-pin configuration. The rated power on those is 75W and 150W respectively, so if the card needs to pull 250W total, it would come in as 75W (slot) + 75W (6-pin) + 100W (8-pin) as opposed to 75W (slot) + 87.5W (6-pin) + 87.5W (8-pin) because the latter is over-drawing from the 6-pin connector.

So yeah, I'd encourage you to get HWSensors and run Ungine Heaven or Valley for a while and see what the power draw looks like. I believe HWSensors can create graphs for you, so you can track the values over time.
 
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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
153
3) The power won't be pulled evenly across both connectors in a 6-pin and 8-pin configuration. The rated power on those is 75W and 150W respectively, so if the card needs to pull 250W total, it would come in as 75W (slot) + 75W (6-pin) + 100W (8-pin) as opposed to 75W (slot) + 87.5W (6-pin) + 87.5W (8-pin) because the latter is over-drawing from the 6-pin connector.

So yeah, I'd encourage you to get HWSensors and run Ungine Heaven or Valley for a while and see what the power draw looks like. I believe HWSensors can create graphs for you, so you can track the values over time.[/QUOTE]

Thanks for the info. It's a good stuff.
I do see the boaster cable draw different wattages.
In my modified HD 7970. 8pin looks like draw 72W at load while 6 pin only draws about half of that and PCIE even lower at around 30W. Given the uneven power draw, I now changed how I arranged for the two HD7970s with internal power from two SATA ports.

But are they accurate enough in the HWsensors app? Because the total wattage draws from one HD7970 at load to be only 135W at Unigine Valley test as I explained. It's 50W lower from what I expected it to be.

Also how do you read the total power consumption (of the Mac PRO) from the HWmonitor? It seemed missing that number or properly categorised. And why the 12v power supply wattage are always similar to the Memory module? Is there any place to see a description of the app?

I would appreciate if some one give inputs.
 
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EdDuPlessis

macrumors 6502
Nov 23, 2014
339
8
Prince134 said:
Thanks for the info. It's a good stuff.
I do see the boaster cable draw different wattages.
In my modified HD 7970. 8pin looks like draw 72W at load while 6 pin only draws about half of that and PCIE even lower at around 30W. Given the uneven power draw, I now changed how I arranged for the two HD7970s with internal power from two SATA ports.
Click to expand...

are you still using the pin trick or also power from the SATA ports?
 
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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
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There is no difference with the pin trick or put a 6 to 8 pin converter for me. I do both. Now on my other thread, if you want to do the dual HD7970 using internal power, you have to put the 2 on-board 6pin to power the 8 pin on both cards since they draw more currents. Therefore the 6 pin on both cards have to connect to two SATA sockets on board.
 
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EdDuPlessis

macrumors 6502
Nov 23, 2014
339
8
Prince134 said:
There is no difference with the pin trick or put a 6 to 8 pin converter for me. I do both. Now on my other thread, if you want to do the dual HD7970 using internal power, you have to put the 2 on-board 6pin to power the 8 pin on both cards since they draw more currents. Therefore the 6 pin on both cards have to connect to two SATA sockets on board.
Click to expand...

Yes thanks I was wondering about that. Is it safe to do for a long time? Do you still run the card like that?
 
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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
153
EdDuPlessis said:
Yes thanks I was wondering about that. Is it safe to do for a long time? Do you still run the card like that?
Click to expand...

Yes, they run fine with FCPX and pretty fast. Dual HD7970s work the same way as the nMP. Two cards work substantially faster than one. Aproximately between 1.5-2.0 factors.
 
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goMac

Contributor
Apr 15, 2004
7,662
1,694
The downside of this approach is if the card ever sends power out through the ground pin, it will be returned through the ground pin, blowing out your card. Possibly taking your computer with it.

So if you don't value your equipment, have at it. The extra ground pins aren't there just to look pretty.

These pins being tricked aren't at all for power pull. So worrying about power draw or load isn't the problem here.
 
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Prince134

macrumors 6502
Original poster
Aug 17, 2010
338
153
goMac said:
The downside of this approach is if the card ever sends power out through the ground pin, it will be returned through the ground pin, blowing out your card. Possibly taking your computer with it.

So if you don't value your equipment, have at it. The extra ground pins aren't there just to look pretty.

These pins being tricked aren't at all for power pull. So worrying about power draw or load isn't the problem here.
Click to expand...

I probably can understand what you mean here.
But the fact is that it has never happened for the past 4 years.

What can I say...:)
 
Macsonic

Macsonic

macrumors 68000
Sep 6, 2009
1,706
97
Prince134 said:
I probably can understand what you mean here.
But the fact is that it has never happened for the past 4 years.

What can I say...:)
Click to expand...

Another consideration is maybe certain computer tasks are more CPU bound than GPU bound. Like some After Effects tasks. There is also the Cinema 4D by Maxxon that is also more CPU bound on some tasks. Maybe only certain specific tasks are GPU heavy. Probably for certain tasks the GPU is using below 200 watts.

http://www.tomshardware.com/answers/id-2119559/adobe-effects-100-gpu.html
http://www.c4dcafe.com/ipb/topic/85492-the-roles-of-the-gpu-and-the-cpu/

One time an electrician was fixing our kitchen wiring and I borrowed his Watts Meter gadget and hook it up to my Mac Pro. I was using a flashed Nvidia 770 gtx which had a 6 pin to 8 pin connector too. It was connected via adaptor, 8 pin to 6 pin adaptor. That time I was playing an After Effects movie and the reading I got was around 297 watts. This reading is for the whole computer. I have no way to telling how much power is the GPU using. So far the 770gtx card works fine in my Mac Pro.
 
mikeboss

mikeboss

macrumors 68000
Aug 13, 2009
1,517
790
switzerland
goMac said:
The downside of this approach is if the card ever sends power out through the ground pin, it will be returned through the ground pin, blowing out your card. Possibly taking your computer with it.

So if you don't value your equipment, have at it. The extra ground pins aren't there just to look pretty.

These pins being tricked aren't at all for power pull. So worrying about power draw or load isn't the problem here.
Click to expand...

the two extra pins aren't for grounding. these are sense pins, just telling the card that there's enough juice coming through the 6 other lines.

http://www.tomshardware.com/reviews/power-supply-specifications-atx-reference,3061-12.html
 
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