See post #1354: https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-55Thanks.
And again: How?))
Especially ways to get around needing the boot screen.
Hallo every oneThis card is not good, because it doesn't have a bios chip on it. If you find one that does, you still need to replace it as the apple rom is 128kb and the bios chip on these is 64kb. So its just too much work. Get a k2000m instead
A black screen is normal because there is no EFI screen on these cards. Do you have any way of telling the iMac is fully booted such as sound when the volume is changing? (The 'pop' sound if enabled) Checking another Mac to see if it's on the network, or having screen sharing enabled? If you are still on a hard drive expect a few minutes before the screen to come on.
I forgot to add check the capslock key. Since it's a 780m like mine. Check the X-Clamp around the GPU and make sure any capacitors aren't touching the X-Clamp. Sometimes the card just needs to be reseated. Do you have a mini displaport monitor near by? I recommend not putting the LCD back on untill you can see the OS booted on an external monitor. Use the thunderbolt port closest to the FireWire 800 port. The fans will run on full speed without the LCD connected because there is a thermal sensor on the LCD.
The caps lock is not on. Update: I just installed the original graphics card again and the whole system works fine, including there is a start up chime. So its obviously a compatibility issue. Please try advise as to how I can make it compatible. Should i intall drivers? I think i might have to get a wired keyboard and display port cable to trial and error it but as of right now, the new gtx 780m does not work
I will continue trying whatever you guys suggest!!!
It's a card/hardware issue, while you have your iMac with the old card installed. Please change the following. Go in to system preference change login to automatic, go into sharing and enable screen sharing. And finally enable volume pop. Again check your X-Clamp and make sure nothing is shorting on it. Please show pictures of the back of your card.The caps lock is not on. Update: I just installed the original graphics card again and the whole system works fine, including there is a start up chime. So its obviously a compatibility issue. Please try advise as to how I can make it compatible. Should i intall drivers? I think i might have to get a wired keyboard and display port cable to trial and error it but as of right now, the new gtx 780m does not work
You have to mod the Heatsink otherwise you are bending the crap out of the card or the die isn't making contact. Please mod the heatsink and remove the thermal pads for testing purposes.
Could you please explain how i 'mod' the heatsink??? Do I need tools to do that? what does it have to look like? What is 'die'? I secured the GPU lightly, i did not use all the screws. I dont think the problem is the pressure of the heatsink. When you started your iMac after installing your upgraded cpu, did you also have a black screen? how did you boot into mac os?
The picture is on page 1 called "heatsink.jpg" I used a Dremel to cut remove excess area of the heatsink so the card sits perfectly flush with the heatsink. The "Die" is the shiney chip on the GPU that does all the processing and produces heat. If you don't know what a "Die" is, I'm questioning whether or not you should be attempting this. If you bent the card because you didn't Dremel the heatink, which has been discussed the the past 70+ pages. You probably broke your card by bending it/breaking traces under the GPU Die.
Correct me if I'm wrong but the heat sink is for transferring the heat right?. Shouldn't the mac turn on without the GPU needing the heatsink? I assume the heatsink is effective after minutes after the mac turns on, But for the initial 1 minute the cpu should just do its job without needing the heatsink. I'm sure I did not damage the GPU yet, I never apply too much force.
When you say it doesn't turn on, do the fans spin for a quarter second and the machine turns off? Makes me think something was shorted on your card. Or the die wasn't making good contact. Pictures please, I've never delt with 6xx card only 7xx cards.
After the first time the mac (turned on but didn't boot the operating system) The gtx 780m was not hot at all, felt like the same temperature as i put it in. I use a 'thermal conductivity heat sink paste which is electrically insulating' - says it on the small box it came in. And yes the mac is not booting at all. Like I said, it turns ON and the fans turn ON like normal but it DOESNT boot into the operating system even though the screen is off. (no caps lock working etc,)
There is something wrong with your card, did you buy it from a seller who sells them in bulk?
one last thing, try it with no X-Clamp but very lightly tighten it to the heatsink. Can I see what your heatsink looks like. You really should mod it if it's the larger 6970m heatsink.
