Mac Pro 3.1 (2008) Metal Graphics Cards Power Cable Issues

[hojkoff_101]

Hello,

I have a Mac Pro 3.1 and am looking to instal macOS Catalina. This will require a Metal enabled graphics card. However, the cards listed all require an 8 pin power lead (with the exception on the K5000). The Pro only has two 6 pin jumpers from the motherboard.

I saw an eBay listing for a GeForce GTX 680 which said, “just plug a 6 pin cable into the 8 pin slot on the card.” Does anyone have any experience doing this? I don’t want to fry my Pro.

I bought a RX 580 without checking properly and it has a 6 pin and an 8 pin slot. I’m reluctant to try two 6 pin power leads at risk of damaging the card, the computer, or both.

I have the K5000 Quadro which is on the list, but it is the Windows version and I don’t get a boot screen which is annoying and something I’d like to rectify.

The alternative is to flash my K5000 with a Mac BIOS. There was on old thread about this from about 8 years ago if I remember correctly which got very heated and didn’t turn up a BIOS. Does anyone know if there is a K5000 Mac BIOS anywhere or is anyone with a Mac card willing to dump and upload it?

Thanks.

 

[pigoo3]

Hello hoof_101,

I can't directly say what you saw on eBay will work or not. I will say that I've seen some of the same spec requirements for installing Catalina on older Mac Pro's requiring a metal enable video card (older technically unsupported Mac Pro's).

Don't know if you've come across this...but here a website where the guy claims to be able to install Catalina on older unsupported Apple computers...and older Mac Pro's. It doesn't seem to require the metal enabled video card....via using his patcher to do the install.

Here's the link...he has a 25 minute video (I didn't watch all of it):

How to Install MacOS Catalina on Unsupported Macs

Want to run MacOS Catalina 10.15 on a Mac, but that computer isn’t on the official list of Catalina supported Macs? Then you may be interested in a third party tool that allows advanced uses …

osxdaily.com

If you give it a try...please let us know how things worked out.

Thanks,

- Nick

 

[hojkoff_101]

Don't know if you've come across this...but here a website where the guy claims to be able to install Catalina on older unsupported Apple computers...and older Mac Pro's. It doesn't seem to require the metal enabled video card....via using his patcher to do the install.

The patcher that links to is exactly what I’ll be using to upgrade. I have used his other patchers to upgrade to Mojave which is technically unsupported on the 3.1. However to go any higher I need a metal enabled graphics card.

I used the Catalina patcher to upgrade in the past. I was only able to use one monitor which is what tipped me off to needing a metal enabled card. That was using a very old graphics card though before I upgraded to a K5000.

It will work with the K5000 I have, but I would like the boot screen back which is why I’m looking to change my current card or flash it if possible. I’d ideally like to flash it actually as I do like the K5000.

 

[pigoo3]

It will work with the K5000 I have, but I would like the boot screen back which is why I’m looking to change my current card or flash it if possible.

I see...thanks for clarifying. You saying Catalina works fine on your Mac Pro 3,1 with the K5000 video card...just missing the boot screen? If so...sounds like you're doing pretty darn good running an OS version (Catalina) that's 4 OS version's beyond Apple's official maximum of macOS 10.11 "El Capitan".

I happen to have a Mac Pro 3,1 sitting right next to me that I don't use that much (has El Capitan installed). I need to find a cheap metal enabled video card so I can try some installs of newer macOS versions.

If you can't find a definitive answer/solution with the current situation...no boot screen seems to be a small price to pay to be able to run Catalina on a Mac Pro 3,1. But I totally understand the desire to overcome that hurdle if there's a solution out there somewhere!

- Nick

 

[hojkoff_101]

I happen to have a Mac Pro 3,1 sitting right next to me that I don't use that much (has El Capitan installed). I need to find a cheap metal enabled video card so I can try some installs of newer macOS versions.

I would definitely recommend the K5000. I managed to pick one up for £95 which is not a bad price to get a good boost for a 3.1. I did get lucky though as that sees to be slightly lower than market rate.

...no boot screen seems to be a small price to pay

You‘re right, and compared to other HW issues, it barely qualifies as a problem. My only desire for a boot screen comes from wanting to enable FileVault. You need the boot screen to see the password being typed in. You can just give it 30 seconds then type it and it’s probably fine, but it is a bit fiddly.

Like you say, small price. It would be nice to fix it though.

I don’t feel comfortable having an unencrypted HDD. If the computer gets stolen, your data is completely vulnerable.

 

[MarkAllread]

I saw an eBay listing for a GeForce GTX 680 which said, “just plug a 6 pin cable into the 8 pin slot on the card.” Does anyone have any experience doing this? I don’t want to fry my Pro.

Hi.
To my recollection you can’t just plug a 6 pin into an 8 pin socket without doing a mod to the cable as the square/round pins don’t match up.
I’ve used a simple 6 to 8 pin adapter on my Mac Pros, (2.1, 3.1 and 5.1) with no issues.

If you do an eBay search you will find them..
Example...
"6 Pin to 8 Pin PCI Express "

 

[hojkoff_101]

I am having lots of issues with this.

I cannot get any output from the K5000 through the display port interfaces at all on either Mojave or Catalina. I also cannot get any output from the DVI ports on the card either. High Sierra is fine. My post above should have stated I have been running High Sierra, not Mojave.

I'm seeing conflicting reports on the internet that Apple have dropped support for display port beyond High Sierra. Is this correct?

I am also having to run both the K5000 and the original ATI card in it. I'm aware this is unorthodox. Is there a way to tell the computer to push the output over the K5000 and not the original card?

 

[hojkoff_101]

The answer to my original question (which Mark has already eluted to) is to use an adaptor which takes the two 6 pin headers on the motherboard to one 8 pin slot for the graphics card, and use a card that only requires one 8 pin power jack.

The consensus on eBay seems to be to use the Sapphire Pulse Radeon RX 580 8G graphics card as shown below taken from a recent auction. You can clearly see the two 6 pin heads being funneled into one 8 pin at the card. Most of the specced out Mac Pros being sold seem to have this in common.

The version of the Sapphire RX580 I have looks to be slightly different and requires an additional 6 pin power input. My one does have a light up go faster Sapphire logo. I wonder if that's what the additional power slot is for....

 

[pigoo3]

My one does have a light up go faster Sapphire logo. I wonder if that's what the additional power slot is for....

I would look at some of the video cards that Apple officially supplied with Mac Pro's (such as the Radeon 5770 and 5870)...and how many pins they needed. If there are some that required all 8 pins...did they have logo's that lit up. Then compare to this Sapphire RX580.

- Nick

 

[MarkAllread]

The answer to my original question (which Mark has already eluted to) is to use an adaptor which takes the two 6 pin headers on the motherboard to one 8 pin slot for the graphics card, and use a card that only requires one 8 pin power jack.

Actually, my input was to use the adaptor to convert a 1X6 cable to a 1X8 cable so you can use two 6 pin cables for those cards that have 1x6 and 1x8 sockets. Sorry if I misread your issue of joining two cable to one.