Can't get my 3rd monitor to work on my Geforce gt 640.

[jackson10t]

I have a geforce gt 640, it has 2 DVI ports and a mini HDMI port. So I have the mini port plugged into my main monitor, the 1st DVI port plugged into my 3rd monitor, then a DVI-VGA convertor plugged into my 3rd monitor. When it boots up. My third monitor lights up with the apple logo and loads ups while the other two are off. Then when the login in screen is about to show up. The third monitor turns off and the other two monitors turn on. I tried to go on settings to activate my third monitor and nothings working. Any advice? thanks.

 

[4pack]

what operating system are you using ?

and have you installed any graphics drivers ?

 

[jackson10t]

what operating system are you using ?

and have you installed any graphics drivers ?

10.8.2, no I haven't since the graphics card is native in 10.8.2. Do I need to install additional drivers to get the 3rd one working?

 

[toleda]

I have a geforce gt 640, it has 2 DVI ports and a mini HDMI port. So I have the mini port plugged into my main monitor, the 1st DVI port plugged into my 3rd monitor, then a DVI-VGA convertor plugged into my 3rd monitor. When it boots up. My third monitor lights up with the apple logo and loads ups while the other two are off. Then when the login in screen is about to show up. The third monitor turns off and the other two monitors turn on. I tried to go on settings to activate my third monitor and nothings working. Any advice? thanks.

GT 640 supports 2 monitors. GTX 650 and higher supports 4 monitors.

 

[4pack]

I don't know how many monitors a 640 supports, I seem to find conflicting info, its a pretty low end card and seeing the reviews I can't really believe that it would be able to support 3 monitors in surround gaming at once at more than 5-6 fps! I have a gtx 670 4gb and surround on high settings pushes that pretty hard to get 40fps +

I guess it may also depend on what model of card you have and the connectors.

I would try the card and setup in windows and confirm if you can get 3 monitors working there? if you can't then I guess you will need another card or an upgrade.
if you can then it should be possible to get it to work on OS X

Try setting boot options to GraphicEnabler=No

Or you can also try installing the Nvidia web drivers here, (I think thee are newer than those in 10.8.2) and are to be included with 10.8.3 as far as I know.

http://www.nvidia.co.uk/object/macosx-304.00.05f02-driver-uk.html

see if that helps any

 

[Cryptic1911]

You need to get the drivers from Nvidia and install them. I just went through this the other day to get my 3rd output working. It was no big deal, just download them and run the installer.

I've got it running dvi to two 20" dell lcd's, and mini hdmi to hdmi to a 32" sharp lcd tv