Graphics Grief

[Ajaycee]

I've got an Early-2008 Mac-Pro, 18GB RAM, Two Monitors (Cinema Display 30" and Cinema Display 20") and running El Capitan.

I've just replaced the original Graphics Card with an ATI Radeon 5770 and the 20" Monitor doesn't wanna play-ball; there is a signal reaching the monitor but it's corrupted, it's clearly getting something but nothing that can be recognised, it's a bit of a mess.

Is this a resolution issue ? if so, can anyone suggest how I can deal with it; technically, I belong in the 'Idiot' category so I'd appreciate words of one-syllable. Kind thanks, Ajaycee.

 

[MC6800]

It's possible. If you haven't already, you could try a lower-resolution setting (System Preferences>Displays>Display>Resolution: Scaled).

 

[Ajaycee]

It's possible. If you haven't already, you could try a lower-resolution setting (System Preferences>Displays>Display>Resolution: Scaled).

It still won't play but thanks for your suggestion.

 

[ActionableMango]

Does your post have a typo? You have to use a dual-link DVI-D cable with the 30" or it will display garbage/snowy picture. The 20" should be fine with any DVI cable. I can't think of what would cause a problem there. Are you using any weird adapters?

 

[jbarley]

I've got an Early-2008 Mac-Pro, 18GB RAM, Two Monitors (Cinema Display 30" and Cinema Display 20") and running El Capitan.

I've just replaced the original Graphics Card with an ATI Radeon 5770 and the 20" Monitor doesn't wanna play-ball; there is a signal reaching the monitor but it's corrupted, it's clearly getting something but nothing that can be recognised, it's a bit of a mess.

Is this a resolution issue ? if so, can anyone suggest how I can deal with it; technically, I belong in the 'Idiot' category so I'd appreciate words of one-syllable. Kind thanks, Ajaycee.

Make sure you have the 30" monitor connected to the DVI output and not the mini display port.

 

[Ajaycee]

Does your post have a typo? You have to use a dual-link DVI-D cable with the 30" or it will display garbage/snowy picture. The 20" should be fine with any DVI cable. I can't think of what would cause a problem there. Are you using any weird adapters?

[doublepost=1476056630][/doublepost]Thanks, although I'm not sure what you're reading as a typo . . . The cable from the 30" Monitor is the one that came with it, I've been using it since I bought the machine with the original graphics card and it's fine. The 20" Cinema Display is connected with the DVI Cable that came with it, it also worked with the old graphics card. The new card has two DVI Ports, I've connected one monitor to each.

An interesting side-comment is that when I start the system up, it briefly shows the 20" Wallpaper in the bottom left-hand corner of the 30" screen, on top of the 30" wallpaper and then disappears; it looks like the system is capable of generating the display output but it's getting corrupted somehow on the way to the smaller monitor; very puzzling. If I go into the settings for the machine, it's registering that there are two monitors; it's a bit of a pain because iTunes always opened to the smaller monitor so I lost all the iTunes controls; I'm working around it for the moment.
[doublepost=1476057005][/doublepost]

Make sure you have the 30" monitor connected to the DVI output and not the mini display port.

Thanks; both monitors are connected to the DVI ports on the graphics card. As sure as I can be, the monitors and the machine are configured exactly as they were with the old card, I literally pulled the old card out, put the new one in and connected it all back up again; as advised, I reset the PRAM and the SMS but the second monitor doesn't wanna play.
[doublepost=1476057070][/doublepost]

Make sure you have the 30" monitor connected to the DVI output and not the mini display port.

Thanks; both monitors are connected to the DVI ports on the graphics card. As sure as I can be, the monitors and the machine are configured exactly as they were with the old card, I literally pulled the old card out, put the new one in and connected it all back up again; as advised, I reset the PRAM and the SMS but the second monitor doesn't wanna play.

 

[jbarley]

[doublepost=1476056630][/doublepost]
Thanks; both monitors are connected to the DVI ports on the graphics card.

sorry about that, I only asked becase my 5770 has only a single DVI + 2 MDSP.

 

[Ajaycee]

PROBLEM SOLVED . . . Thank you to all who offered suggestions so quickly, I am most grateful.

For some reason, best known to the computer gremlin, it's now working and having done nothing to resolve it; I simply switched it on today and hey-presto, problem solved. As I have said, my thanks again for all your suggestions, it's encouraging to know that so much help is available here. Kind Regards, AJC.

NOTE:
For what it's worth, I've just taken the latest update for El-Capitan and on restarting, the same problem occurred . . . The Solution: put the machine to sleep and when it wakes-up again, the second monitor is fine - I have no idea what that's all about but it's working.