Resolved MAC PRO 4,1 and 5,1 PCIe AUX Power

[Reindeer_Games]

@h9826790
I installed the powerlink a couple of days back and all is in order. I did, however, notice my PSU stopped buzzing (from time to time) after installing the powerlink which is super great!! Can someone with the powerlink installed confirm this?

I wasn't getting any audible sounds, but I have logged considerably less voltage spikes after installing mine. I will note that I have observed the route the GPU draws power (between either via PCIe boosters or the PCIe slot), depends on how the Powerlink is connected as well as whether the GPU is in slot 1 or 2.

When my card is in slot 1 and looking at the Powerlink w/ push tabs up:
PCIe Booster A 6-pin routed to 8-pin Jumper 2 (R)
PCIe Booster B 6-pin routed to 8-pin Jumper 1 (L)
...power is primarily drawn from the PCIe Slot (Slightly higher slot use at idle with spikes, booster spikes are minimal under load).

When my card is in slot 1:
PCIe Booster A 6-pin routed to 8-pin Jumper 1 (L)
PCIe Booster B 6-pin routed to 8-pin Jumper 2 (R)
...power is primarily drawn from the PCIe Boosters (Low slot use at idle minimal spikes, booster spikes are considerable, but smoother than prior to Powerlink).

I'm noticing only about .5 A variance at idle-but under load there are considerable differences (over 2 A).

Based on what I can remember of Ohm's Law is why I am presuming that it will be inverted vice versa if my GPU where sitting in slot 2, but can anyone confirm my observation?

 

[w1z]

I wasn't getting any audible sounds, but I have logged considerably less voltage spikes after installing mine. I will note that I have observed the route the GPU draws power (between either via PCIe boosters or the PCIe slot), depends on how the Powerlink is connected as well as whether the GPU is in slot 1 or 2.

When my card is in slot 1 and:
PCIe Booster A 6-pin routed to 8-pin Jumper 2 (R)
PCIe Booster B 6-pin routed to 8-pin Jumper 1 (L)
...power is primarily drawn from the PCIe Slot.

When my card is in slot 1 and:
PCIe Booster A 6-pin routed to 8-pin Jumper 1 (L)
PCIe Booster B 6-pin routed to 8-pin Jumper 2 (R)
...power is primarily drawn from the PCIe Boosters.

Based on what I can remember of Ohm's Law is why I am presuming that it will be inverted vice versa if my GPU where sitting in slot 2, but can anyone confirm my observation?

I haven't noticed any difference and the power draw is spread out evenly. I noticed from your setup that you connected 2 x mini 6-pin to 8-pin cables to the powerlink while I went with 2 x mini 6-pin to 6-pin cables to avoid overloading the PCIe boosters.

My card requires an 8-pin and a 6-pin connection.

 

[Reindeer_Games]

I haven't noticed any difference and the power draw is spread out evenly. I noticed from your setup that you connected 2 x mini 6-pin to 8-pin cables to the powerlink while I went with 2 x mini 6-pin to 6-pin cables to avoid overloading the PCIe boosters.

My card requires an 8-pin and a 6-pin connection.

Doesn't matter just as h9826790 said, it's all going through the 2x 6 pins at the source-but meant it as reference to the 8-pin Jumpers. My current 770 has a 6 and 8 pin port as well, you won't as long as stay below a 230w GPU but even my 770 has been causing odd PSU heat and I think this is the culprit since I haven't had any issues since swapping to the first setup I listed.

The Powerlink is awesome-good choice-just trying to offer a suggestion on what may have been causing your noise since it would be worse prior to installing a Powerlink due to the completely separate A and B power channels never meeting.

 

[Eweie]

I got an MSI gaming x rx 580 with 185 W power requirement and many of the posts here suggest I should be able to run it with just one six pin to 8 pin adapter but that's clearly not the case. the card boots into mac os with no hardware acceleration and in won't even boot at all in windows.
this seems indicative that it is in fact correct the the 6 pin slots regardless of cables will only output 75 watts.
I currently don't have a proper two six pin to one eight pin adapter but I recon that should fix my issue.

 

[Reindeer_Games]

I got an MSI gaming x rx 580 with 185 W power requirement and many of the posts here suggest I should be able to run it with just one six pin to 8 pin adapter but that's clearly not the case. the card boots into mac os with no hardware acceleration and in won't even boot at all in windows.
this seems indicative that it is in fact correct the the 6 pin slots regardless of cables will only output 75 watts.
I currently don't have a proper two six pin to one eight pin adapter but I recon that should fix my issue.

Dual mini 6-pins to single 6+2 pin (or 8 pin) will work to power a Pulse 580. The RX 580 design draws more heavily on the 8-pin booster than on the slots, which is why it can cause a shutdown with only one booster connected under heavy load.

A GPU would have to be below ~120w to be able to run full render without the danger of a shutdown on a single slot/booster.

 

[tsialex]

A GPU would have to be below ~120w to be able to run full render without the danger of a shutdown on a single slot/booster.

Mac Pro 5,1 PCIe AUX is rated to 75W. You can use it over the specified rating, some people noticed the power cut is around 120W, but this will drastically reduce the backplane useful life.

 

[Reindeer_Games]

Mac Pro 5,1 PCIe AUX is rated to 75W. You can use it over the specified rating, some people noticed the power cut is around 120W, but this will drastically reduce the backplane useful life.

Understood, thats why I said slot and booster-which would peak ~90w in the most drastic of cases of 3:1 ratio pulling on the booster over the slot power, but their RX580 is well above 120w. I agree pushing any power limit for long will reduce the lifetime expectancy of the backplane, and why I suggested they connect both boosters for their RX580; I'm sorry if I was not clear and you are correct, I should have elaborated (and be better about nomenclature). I apologize.

My calculations include using a basic 3:1 ratio for a 185w RX580 that could theoretically peak at 138.75w; and on a single PCIe auxiliary that will definitely trigger a shutdown and add additional PSU/Backplane electrical wear and tear you want to avoid. Divide that by two PCIe auxiliary and you have a theoretical 69.375w draw, slightly below the rated spec; both boosters are needed for long-term workloads on a RX580.

 

[Eweie]

Dual mini 6-pins to single 6+2 pin (or 8 pin) will work to power a Pulse 580. The RX 580 design draws more heavily on the 8-pin booster than on the slots, which is why it can cause a shutdown with only one booster connected under heavy load.

A GPU would have to be below ~120w to be able to run full render without the danger of a shutdown on a single slot/booster.

I got the 6 pin to 8 pin adapter sadly my card does not work still. I'm wondering if I got a bad cable or a bad card.
one thing I noticed that the sense B in my adapter was connected to ground and one of the six pin female connectors is missing the sense A cable, is this normal? the other does have it and it connects correctly to the sense A of the 8 pin male plug.

 

[Reindeer_Games]

I got the 6 pin to 8 pin adapter sadly my card does not work still. I'm wondering if I got a bad cable or a bad card.
one thing I noticed that the sense B in my adapter was connected to ground and one of the six pin female connectors is missing the sense A cable, is this normal? the other does have it and it connects correctly to the sense A of the 8 pin male plug.

There may be a language barrier here so I'll do my best to assume what you are asking-and I am presuming you meant you received your dual mini 6 pin to 8 pin Aux booster cables.

All terminals should have wires from the mini-6 pin jumper to the 8 pin jumper side.

I'm not sure of how you described it, but if it's not in the described arrangement above- you may want to try another cable vendor-because my Pulse RX580 runs great OOTB off the dual mini 6 pins to 8 Pin.

EDIT: Removed incorrect portion of information, similar polarities of the 6 pins are blended to make the 8 pin power.

 

[Eweie]

There may be a language barrier here so I'll do my best to assume what you are asking-and I am presuming you meant you received your dual mini 6 pin to 8 pin Aux booster cables.

The 6 pin jumper is composed of 3 positive and 3 negative terminals, which are spilt on the top and bottom of the 6 pins (if looking at the backside of the jumper, clasp on-top). An 8 pin is composed of 5 positive and 3 negative terminals, arranged in the same fashion as the 6 pin-but with two more positives vertically on the left side of the jumper. The dual mini 6 pin-to-8 pin adapter blends these into a properly powered 8 pin jumper, all terminals should have wires from the mini-6 pin jumper to 8 pin jumper side.

I'm not sure of how you described it, but if it's not in the described arrangement above- you may want to try another cable vendor-because my Pulse RX580 runs great OOTB off the dual mini 6 pins to 8 Pin.

there is no language barrier, I speak perfect English. there is no other way to describe what I said.

sense B is connected to ground and sense A is missing on one female but not on the other.

can someone else verify this is correct?
[doublepost=1553057558][/doublepost]Here is the cable. Afaik everything else is correct.

 

[Reindeer_Games]

you may want to try another cable vendor

there is no language barrier, I speak perfect English. there is no other way to describe what I said.

sense B is connected to ground and sense A is missing on one female but not on the other.

can someone else verify this is correct?
[doublepost=1553057558][/doublepost]Here is the cable. Afaik everything else is correct.

Are you asking someone else to verify your cable is not wired correctly without showing a picture or something?

I don't know what a sense B is, I apologize if I offended you-but I thought you meant Aux Booster cable and really have no idea why you are referencing male/female connector types (unless you aree talking about pins?). I only made my cable myself from extra parts laying around-which is why I suggest you try another vendor, and ensure it's in the described design above; there are plenty available online.

 

[Eweie]

Are you asking someone else to verify your cable is not wired correctly without showing a picture or something?

I don't know what a sense B is, I apologize if I offended you-but I thought you meant Aux Booster cable and really have no idea why you are referencing male/female connector types (unless you aree talking about pins?). I only made my cable myself from extra parts laying around-which is why I suggest you try another vendor, and ensure it's in the described design above; there are plenty available online.

1: I did post a picture
2: "I don't know what a sense B is" have you looked at the schematic? it's right on the first page.

 

[Reindeer_Games]

1: I did post a picture
2: "I don't know what a sense B is" have you looked at the schematic? it's right on the first page.

1) My apologies didn't hit refresh fast enough.
2) Nope. It very well may be.
3) That wiring is not right; for sure. Track that exact wire from the 8 pin side and see if it crosses polarity anywhere, it should be bottom middle right (that could easily cause a shutdown). But def get a replacement long-term, IMO.

 

[Eweie]

1) My apologies didn't hit refresh fast enough.
2) Nope. It very well may be.
3) That wiring is not right: you don't have a good enough ground, for sure. Track that exact wire from the 8 pin side and see if it crosses to a positive anywhere, it should be bottom middle right (that could easily cause a shutdown). But def get a replacement long-term, IMO.

Everything is as it should be but maybe I missed something in the person's posts, if sense b is normally bridged to ground. I believe I've seen this in other cables.

as mentioned before my sense A is missing on one of the female ends but not in the other. I am wondering if this would somehow cause the computer to not power up that cable fully.

My card is exhibiting clear signs of being underpowered, the seller sustains the card was working perfectly before shipping.
It was tested in two different 5,1s so I would rule out any sort of PSU failure. one of them is running a more power hungry gtx 970.
[doublepost=1553061365][/doublepost]I just tried powering my 970 with that cable alone. the card has a 8 pin and 6 pin connector but I believe it should work with just the 8 pin connected. the 970 also did not work.
I think this cable just doesn't work.

 

[Reindeer_Games]

Removable power tabs from a Powerlink.

Everything is as it should be but maybe I missed something in the person's posts, if sense b is normally bridged to ground. I believe I've seen this in other cables.

I just tried powering my 970 with that cable alone. the card has a 8 pin and 6 pin connector but I believe it should work with just the 8 pin connected. the 970 also did not work.
I think this cable just doesn't work.

 

[Eweie]

View attachment 827268
Removable power tabs from a Powerlink.

ok so that's good. so I guess the only problem might be the missing sense A cable.
[doublepost=1553064434][/doublepost]I bridged the sense A to a ground and it still doesn't work. I've lost hope and I'm returning the card.
I ordered a complete cable from amazon, not an adapter but I dont have faith in the GPU. I'll get another rx 580 and hope it works.

 

[Eweie]

Hey. just wanna report that it wasn't the cable. so if you find a cable that is like mine missing that one connection and your GPU doesn't work, you need to re-install Mac OS. that fixed it for me.

 

[Hdalio]

i everybody, I got a TITAN X and I want to know the best way to install the power on the board!

This is the scheme I thought:
- 2 mini 6pin to 8pin - connected in 8pin card!
- power sata to 6 pin - connected in 6pin card + extender

I'll get the extra SATA connection next to the super drive.

Does this sata pass how many watts of power? Can I run with only 1 sata power or would it be better to use the sata power to super drive as well? so I would need a 2x power cable Sata to 6 pin + extender!

Thank you

 

[Pentaxer]

Does this sata pass how many watts of power? Can I run with only 1 sata power or would it be better to use the sata power to super drive as well? so I would need a 2x power cable Sata to 6 pin + extender

Look p. 3.9.1.
https://forums.macrumors.com/threads/gpu-compatibility-list-for-cmp.2174600/

 

[thornslack]

2 satas combined to single 6 is probably better. I ran my Tx off internal power only using a mini 6 to 8 pin without major issues until I eventually got a power link.

 

[Hdalio]

Okay, I get it, the only question is if I use the 2 SATA to feed the 6 pin or 8 pin of the card!
If I use the SATA to pin 6 can I use more than 75w? Can this be a problem?

Or would it be better to use the 6pin to 6pin and the 2 SATA to an 8 Pin? Would you give the required 100W that is missing for the card?

The card is 250W!

 

[zackkmac]

Quick question. This thread has a lot of good explanations but I just want to be sure I know what I'm doing to my cMP:

I've installed an RX480 8GB OC and used the stock 6-pin connector, does that mean it's running on 150w (75w from PCIe and 75w from the cable)? Do I really need the 8-pin adapter and if so, specifically which one?

I've got the card set to power efficiency mode (there's a physical switch on the card itself) and it seems to do fine with my current usage, which does include moderate gaming. But I don't want to be prematurely wearing out my backplane or GPU.

 

[h9826790]

Okay, I get it, the only question is if I use the 2 SATA to feed the 6 pin or 8 pin of the card!
If I use the SATA to pin 6 can I use more than 75w? Can this be a problem?

Or would it be better to use the 6pin to 6pin and the 2 SATA to an 8 Pin? Would you give the required 100W that is missing for the card?

The card is 250W!

If you want to be safe, you should use

Dual mini 6pin -> single 8pin
Dual SATA -> single 6pin

You will need 3 SATA ports to support a single 8pin, not 2.

 

[startergo]

Quick question. This thread has a lot of good explanations but I just want to be sure I know what I'm doing to my cMP:

I've installed an RX480 8GB OC and used the stock 6-pin connector, does that mean it's running on 150w (75w from PCIe and 75w from the cable)? Do I really need the 8-pin adapter and if so, specifically which one?

I've got the card set to power efficiency mode (there's a physical switch on the card itself) and it seems to do fine with my current usage, which does include moderate gaming. But I don't want to be prematurely wearing out my backplane or GPU.

Not really. The draw from the pcie slot is below 40 Wats. It is around 24W. So the rest has to be provided from the pins. I found that with a single 6mini pin furmark test in Windows under certain conditions leads to a shutdown. I recommend 2 mini 6 pins to 6 pin. This is what I use on mine RX-580 DELL OEM

 

[Hdalio]

If you want to be safe, you should use

Dual mini 6pin -> single 8pin
Dual SATA -> single 6pin

You will need 3 SATA ports to support a single 8pin, not 2.

So I thought so.
Sloth 75W
6 Pin> 6 Pin 75W
2 Power Sata> 8 Pin 100W
Total 250 W

the way you told me
Sloth 75W
dual mini 6 Pin> 8 Pin 150W
2 Power Sata> 6 Pin 100W ??
Total 325 W ??

and its only using 1 power sata for the 6 Pin?