iMac 2011 GPU Upgrade Display Problem GTX675MX

moorhad

macrumors newbie
Original poster
Dec 13, 2013
9
0
Hi.

Just put a GTX 675MX in my Imac 2011.
When i powered up the Display doesn't show anything.

BUT....

When the Thunderbolt Display is Connected the Desktop
of the Thunderbolt is shown up.

So what is wrong here?
 

moorhad

macrumors newbie
Original poster
Dec 13, 2013
9
0
When I start the iMac it powers on.
But I get no screen on the iMac.
When I connect my Thunderbolt Display
Into the iMac I get a screen but only on the
Thunderbolt Display.
The screen of the iMac is black.
It also doesn't recognize the iMac screen
in the settings.
 

goodcore

macrumors newbie
Jun 24, 2013
15
3
Putinville
When I start the iMac it powers on.
But I get no screen on the iMac.
When I connect my Thunderbolt Display
Into the iMac I get a screen but only on the
Thunderbolt Display.
The screen of the iMac is black.
It also doesn't recognize the iMac screen
in the settings.
Now I get it. How I know, you need modified bios or drivers for videocard. Also, can you make screenshot for proofing?:p
 

moorhad

macrumors newbie
Original poster
Dec 13, 2013
9
0
Gonna post it tomorrow...
But if I need modified bios or something why does it work with an external monitor?
The card is identified as a GTX 675mx 4096.
So everything seems to be fine...
 

joe-h2o

macrumors 6502a
Jun 24, 2012
997
445
You should probably hide your serial number - it's visible in those photos.

It also sounds like the 675MX needs a custom firmware to make it compatible with the iMac.

I assume all the internal cables have been reconnected? The iMac's internal display is run over a DisplayPort connection - this may not be visible to the new GPU if it's a port on the logic board without a specific Mac firmware.
 

moorhad

macrumors newbie
Original poster
Dec 13, 2013
9
0
hmmm.but in the new imacs there are some which provide this card so there must be a firmware..where can i get this...?
 

joe-h2o

macrumors 6502a
Jun 24, 2012
997
445
hmmm.but in the new imacs there are some which provide this card so there must be a firmware..where can i get this...?
People have asked users that have the 675/680 GPUs to use the firmware dump tool to extract it so that it can be used to flash other cards, but as far as I know this has been unsuccessful with the late 2012 iMac for some reason.

Macvidcards might have more information.
 

jaxhunter

macrumors regular
Dec 14, 2012
118
15
Maryland Eastern Shore
I believe the 2011 iMacs used a standard LVDS connection and the 2012 and later switched to an internal MiniDisplayPort connection. They may be physically identical connectors but they used different protocols. Either that, or you missed a connection or damaged one. The two suspects would be the main data cable or the backlight cable, though if it were the latter the machine would behave as if the internal display was attached.
 

moorhad

macrumors newbie
Original poster
Dec 13, 2013
9
0
Ok...I was a bit afraid....so I put my old card back and everything is fine..
There is no damaged connectors...
 

moorhad

macrumors newbie
Original poster
Dec 13, 2013
9
0
Just wrote to this guy on eBay.
And he answered:

Sorry, we do not work with iMacs or offer free tech support.
Thanks !!!

:/
 

SilvioM

macrumors newbie
Mar 10, 2013
16
0
Hi.

Just put a GTX 675MX in my Imac 2011.
When i powered up the Display doesn't show anything.

BUT....

When the Thunderbolt Display is Connected the Desktop
of the Thunderbolt is shown up.

So what is wrong here?
What if you could get the bios from the GTX 680MX of a 2012 iMac and flash it onto the GTX 675MX? That might work
 

moorhad

macrumors newbie
Original poster
Dec 13, 2013
9
0
I don't know someone who has this model.
Maybe someone in this forum can do this!?
 

jaxhunter

macrumors regular
Dec 14, 2012
118
15
Maryland Eastern Shore
The issue is not typical of a firmware issue...

Typically if a PC video card is installed in a Mac then you will not get boot screens on any display but once the OS loads and the OS drivers are running then you get full display.

This is a different kind of incompatability.

Also, you should not flash a 675 with 680 firmware. Stick with like for like if you're going to play around with something like that.
 
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