MAC PRO and Geforce GTX 980 ti

I would contact MacVidCards directly to have them address this issue, but i would venture to guess that it's an insufficient power issue? Did you connect both PCIe power cables to both the motherboard and the video card?

To the point of my own question: Is there any significant advantage to going with the 980Ti 6GB and its potential power problems (like perhaps piazza is experiencing) over the less power-hungry 980 4GB?

The 980Ti needs at least an 8-pin and 6-pin power source; I've seen videos where the existing dual 6-pins are merged via adapter to the 8-pin port on the card, and then a SATA power source is used to power the 6-pin port on the card. But from what I can tell, the Mac flashed 980Ti's being offered by several sources appears to just rely on the existing dual 6-pin PCIe power connectors.

Can anyone clarify this?

Yes, the 980ti needs both cables, the 6 pin and the 8 pin. A T-shaped adapter cable that splits one motherboard connector to both power connectors on the video card will overload the connector on the motherboard. So you allways need two distinct cables to operate the 980ti.

To say it precisely, according to specifications, the 980 ti at its highest performance level will use a few watts more then the mac motherboard can supply. But ... i have my mp 5.1 / 2010 and the 980 ti for a year now, and even with some gpu hungry games at the bootcamp / windows side the system never crashed.

greetings from germany

Chris

Thanks for corroborating what I've watched on a video that drew additional power from a SATA source, and other user experiences posted elsewhere that also have not yet bumped up on the max power draw of the Ti that would cause a shut down of the Mac.

As I have all 4 drive bays populated with 4TB (Green) drives, plus two Samsung 850 Pro SSDs RAID'd on a Tempo SSD Pro, an Apple Fibre Channel card connected to an Xserve RAID, and finally a Sound Blaster Titanium card (for PC games), the only "free" SATA source is my second optical bay. But I think with all those power-drawing add-ons, I should stick to the 4GB 980 version as I may be more susceptible to overloading the MP PS.

There is no need to use the second optical as power source, on the motherboard of the mp there are two power connectors for the gpu.

Hmm, has there been a problem with 6 to 6 and 6 to 8 pin cables?, ask at macvidcards which cables you need. It is about a year ago i inserted the 980 ti, memory can be misleading.

greetings from germany

Chris

I thought the 2 motherboard 6-pin PCIe power connectors merge into the 8-pin connector on the card, therefore another power source must be located for the 6-pin...?

That's how this person did it: https://www.youtube.com/watch?v=D7FoB-bSNV0

He used two drive bay SATA power connectors merged into a single 6-pin PCIe that plugged into the 6-pin connector on the card.

So are you telling me that you simply used a 6-pin PCIe to 8-pin PCIe adapter to connect one of the motherboard PCIe ports to the 8-pin plug on the video card, while connecting the other 6-pin PCIe directly to the 6-pin plug on the video card?

FYI, I currently have a Radeon 5870 that uses both PCIe power connectors on the motherboard.

No. There are 6 to 6 cables, and 6 to 8 cables.

The 6 to 8 are a emergency solution, but they work.

greetings from germany

Chris

... and now ... i must prepare for silvester ... and a happy new year ... shall the firecrackers make kabooom 🙂, and not thy motherboard 👿

I'm actually having problems with the 4gb version. Not the ti. It came with two cables, a 6 to 6+2 and a 6 to 8. I connected both, of course only using the 6 and not the +2 on the first cable as there isn't even a place for the +2 on the card. Macvidcards has asked me to send clear images of the back of the card. Not sure what he is looking for but hopefully he will be able to figure out what's wrong.

@piazza: Yea, I'd definitely keep at it with MacVidCards, especially as it hasn't worked at all from the box.

It's interesting that MacVidCards supplied a 6-to-6+2 and a 6-to-8 pin PCIe power cables. Standard 4GB 980's come with two 6-pin connectors, but special edition (e.g. Kingpin) and factory over-clocked versions (all still 4GB VRAM) come with at least one 8-pin connector; some with two 8-pin connectors. Thus, those special 980's would require at least the same power capacity as a Ti version.

I'm assuming if you connected both cables, including the 6-to-8 pin cable (meaning you have an 8-pin connector on your card), your 980 probably is a special edition/over-clocked version...

some more information about cpu and ram upgradability, scroll down to mac pro 4.1, 5.1

https://forums.macrumors.com/threads/mac-pro-cpu-compatibility-list.1954766/

greetings from germany

Chris

Thanks mate :-)