MP 1,1-5,1 Solved / Questions about powering R9 280x

[vworks]

Hello,




I just bought a r9 280x OC Powercolor second hand and flashed it for my mac pro 5.1. The flashing went fine, I have bootscreen.
Now my question is more about powering the card.


I use 1x6 pin and 1x6 pin+adaptor 6 to 8 pin cables. I have read a lot in the forums and it seems that this should work fine.
Indeed it works in Windows and OS X.
BUT.
I always test my cards under Furmark. The ones I owned before, never shut down the machine but this one did, after 3-4 mins 1600x900 stress test (and the card was very hot).
What I noticed is :

- strange noise like whistle or hissing, I think it is coming from the PSU
- the fans begin to spin at greater speed only when the card reaches 80 °C, until then they work at 30-40 % (also I noticed in a general way the card is very silent)

I opened the card, cleaned it, replaced the thermal paste and cleaned the fans as well and oiled them.
I retested in furmark, same whistle and I quit before the mac shuts down.



In OS X and normal use in Windows it is ok, I barely hear it. But I am getting the strange feeling something is not OK.
I ordered more cables (pci-sata) to feed the 6 pin with 2 sata ports and one 8 pin->2x6 minipins for the mini pci-e ports on the logic board, which should normally be the way to power the card.


OK now 2 questions :



1. I checked in VBE7 the original PC bios and found out the curve is different from the cards I had before. Indeed the curve make the fans speed up only after 70°C. If I modify this curve and save the bios and flash it afterwards, is OS X keeping these values or it is only Windows that uses that?

2. Do you think that this shut down is related to some problem of the card itself? I am sure the PSU of the machine is fine because I used it with several card and never had this problem. (Besides this furmark problem, the card is really , OK, no other problems so far, but I have it for a couple of days only).





Thank you for your assistance!

 

[MIKX]

Although this thread concerns powering a Sapphire Dual-X HD 7970 the R9 280X has the same 8 pin & 6 pin power sockets.
I highly recommend buying an EVGA PowerLink which will 'smooth out' all supplied power to the R9 280X and also a DUAL SATA to single 6 pin cable.

EVGA PowerLink with AMD GPUs

Just got the EVGA PowerLink working with my Sapphire Dual-X 7970 3gb. IMPORTANT : The power input sockets on the PowerLink are 2 X 8 Pin female and cannot be changed. The EVGA PowerLink ensures that exact power demanded by a GPU is supplied. That said, one must still supply enough power to...

forums.macrumors.com

 

[h9826790]

1. I checked in VBE7 the original PC bios and found out the curve is different from the cards I had before. Indeed the curve make the fans speed up only after 70°C. If I modify this curve and save the bios and flash it afterwards, is OS X keeping these values or it is only Windows that uses that?

OSX always obey the VBIOS's parameters for 280X.

You can downvolt the card, mod the fan curve, do whatever you want in VBE7. Then use the Netkas script to make the new EFI ROM. (You MUST obey this order, VBE7 will disable EFI. Of course, you can also manually re-activate the EFI part by hex editing the ROM. But in general, use the Netkas is easier, especially you know how to use it)

P.S. I owned few HD7950 / R9 280 before. All of them are seriously overvolted from factory. The worst one shipped with factory setting at 1.094V, but the card only need 0.888V to run stably. Downvolt the cards can make them run much cooler and quieter. Since you have Windows, I highly recommend you to find out the minimum stable voltage for your card, and downvolt the ROM in VBE7 accordingly.

2. Do you think that this shut down is related to some problem of the card itself? I am sure the PSU of the machine is fine because I used it with several card and never had this problem. (Besides this furmark problem, the card is really , OK, no other problems so far, but I have it for a couple of days only).

99% you triggered the shutdown protection because draw too much from ONE of the mini 6pin.

You new cables should work. But just let you know that this "power balancing method" also work.

How to - downvolt a Radeon VII

Can. However, my recommendation is balancing the demand between the mini 6pins. If you re-read my post #35 again, you should able the see that the power draw via each mini 6pin is very balanced. The reason is because I use a cable combination to balance the demand. "DUAL mini 6pin -> Single...

forums.macrumors.com

 

[MIKX]

vworks

it would help if you could tell us who makes your R9 280X.

Sapphire ? Gigabyte ? MSI / etc.

The XFX GPUs are generally not recommended as they often differ from the AMD reference standard.

Additionally, your R9 280X if it is true to teh AMD reference design has a BIOS SWITCH. This switch should be set to Position #2 prior to EFI flashing = shut down & change the switch to Position #2

NOTE : Some XFX R9 280X GPUS do not have te BIOS SWITCH

 

[vworks]

vworks

it would help if you could tell us who makes your R9 280X.

Sapphire ? Gigabyte ? MSI / etc.

The XFX GPUs are generally not recommended as they often differ from the AMD reference standard.

Additionally, your R9 280X if it is true to teh AMD reference design has a BIOS SWITCH. This switch should be set to Position #2 prior to EFI flashing = shut down & change the switch to Position #2

NOTE : Some XFX R9 280X GPUS do not have te BIOS SWITCH

Thanks! It is as mentionned in the first post POWERCOLOR OC (it is overclocked). It has also the dual bios switch, very helpful feature.
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Downvolt the cards can make them run much cooler and quieter. Since you have Windows, I highly recommend you to find out the minimum stable voltage for your card, and downvolt the ROM in VBE7 accordingly.

Thanx! That is the part I am not too familiar with - downvolting. I will check the link you posted, hoping it explains the downvolting. I am pretty sure this has been factory overover clocked for game purposes...
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Although this thread concerns powering a Sapphire Dual-X HD 7970 the R9 280X has the same 8 pin & 6 pin power sockets.
I highly recommend buying an EVGA PowerLink which will 'smooth out' all supplied power to the R9 280X and also a DUAL SATA to single 6 pin cable.

MIKX, this EVGA adapter is really necessary? It is some kind of transformator? I read the first page of the link, I will finish later because I have to go now...
Thank you!!

 

[MIKX]

Apologies, didn't notice that you had included "Powercolor" in your first post.

 

[h9826790]

Thanx! That is the part I am not too familiar with - downvolting. I will check the link you posted, hoping it explains the downvolting. I am pretty sure this has been factory overover clocked for game purposes...
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Post #1 step 1 in that link explain the simple way to find out minimum stable voltage. Same method also applicable for 280X.

If you have time, after downvolt in Unigine Heaven, you better also run Luxmark, Unigine Valley, Furmark, and OCCT to confirm stability.
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this EVGA adapter is really necessary? It is some kind of transformator? I read the first page of the link, I will finish later because I have to go now...
Thank you!!

It's not necessary, but make your life easier.

With the PowerLink, you can power pretty much power any 6+8 pin card on the cMP without any issue.

The PowerLink is just a bridge to merge all power source / demand together. No transformer inside.

e.g. 65W from the 6pin, and 130W on the 8pin from your card.

With the PowerLink, it become a single 195W demand via PowerLink.

And it demand 195W from BOTH mini 6pins, which means, each mini 6pin only need to deliver just a bit below 100W.

This is the key to keep you away from the shutdown protection.

Otherwise, the 8pin draw 130W from ONE of the mini 6pin, that will trigger the shutdown protection straight away (but the other mini 6pin is still under utilise, and only delivering 65W).

There is also capacitors build inside the PowerLink to smooth out power spike.

For 280X, that doesn't really matter. But for something like GTX 1080Ti, the power spike can also trigger the shutdown protection. And PowerLink help to avoid that.

 

[vworks]

h9826790,


That was pretty clear, thank you. As usual

 

[vworks]

Dear @h9826790,


I dont have the wattage/voltage option under my Radeon settings... Is there another method to do it?
May be in VBE directly putting less voltage each time and flash the bios until some artefacts appear? This is gonna be a lot of work but if there is no other choice...



Thanks
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Are these the tabs to "play" with?
If so, what would you change here to begin?
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I put also the fan speed scheme of the card

 

[h9826790]

Dear @h9826790,


I dont have the wattage/voltage option under my Radeon settings... Is there another method to do it?

Use MSI Afterburner to set the voltage

 

[vworks]

I got the cables and now everything is fine :

1 8 pcie pin -> 2x6 mini pcie (PCIe boost on the screenshot)
1 6 pcie -> 2 x Sata (connected to 2 sata ports HDD2 and 3 on the screenshot)


Card has been undervolted to 1070 VDDC and clock is running at 950 mhz.


iStat gives this, under load the 2xSata hit almost 1,70 A but not further.

Thanks!!!