MP 1,1-5,1 ATI Radeon HD 5770 AND 5870 inside Mac Pro 5,1?

[FirDerrig33]

Hi everyone! I have my trusty Mac Pro 5,1 (12 core 2.66) and wondering if having the 5870 in slot 1 and the 5770 in slot 2 would work fine or if it is even advisable. My current 5770 is starting to not perform well and my 27" mDP ACD shuts off and then comes back on from time to time while my 2005 23" ACD with DVI isn't affected (and that's connected vi mDP-DVI adapter).

Thanks in advance for any assistance!

 

[MarkC426]

The 5870 needs 2 power connectors, and the 5770 needs 1, so you do not have enough power.

 

[FirDerrig33]

The 5870 needs 2 power connectors, and the 5770 needs 1, so you do not have enough power.

I guess I should have sen that coming btu I was still looking for a way around it. :-|

Basically I'm trying to find the least expensive gpu upgrade that will continue to support my 2 displays. My hope was to have the 5870 support the 27" MDP and the 5770 support the 23" ACD.

Do you thik the Nvidia GeForce GT 120 from the 4,1 would work? It's a single lane card that doesn't require extra power and that is capable of supporting the 23" display for sure.

To be clear I use my MP as mostly a home computer. I do some Steam gaming but nothing really very demanding and I burn a lot of Blu-rays to put import into my iTunes.

I also am not very interested in upgrading to Mojave so a Metal capable card is not something I really care about since that would also make me have to get adapters to work with my mDP display.

 

[MarkC426]

Why not connect both monitors to the 5870?

 

[FirDerrig33]

Why not connect both monitors to the 5870?

I don't have the 5870 yet and was trying to figure out if it was worth it or not. Lately my 5770(I'm asuming) has been glitching. My mDP display will shut off and then all my windows will move to my ACD. Then it will come back on.

I removed it, cleaned it, made sure that it was plugged into power slot A, reconnected it and even after that it still exhibited the same behavior. It hasn't happened so far today but that's what I'm thinking the problem is.

 

[MarkC426]

Have you tried a different cable?

 

[FirDerrig33]

Have you tried a different cable?

No I only have the one. I just recently got this Mac Pro after wanting it for some time. I contacted the seller and they said that their staff and techs normally flash every GPU to make it work with Mojave. I thought that easing the HDD and reinstalling Mac OS High Sierra with the 5770 in there would have reverted whatever flashign they did. It was enough for them to offer a $100 refund for me to replace the card.

Right now it has been working mostly fine. I just feel like I need to find either an additional card to take the load off of this one or replace it completely and not sure if I want to do that due to the cost.

 

[Nguyen Duc Hieu]

Get a PC card, then.
AMD: R9 280x will work fine. No boot screen.
Nvidia: GTX960 will need nvidia web driver installed before plugging in the card, but it work fine in High Sierra. No boot screen.

They have both the port you need: Display Port and DVI