What do I need to run 3 moniters?


Apr 5, 2011
Hi, I've got 2 moniters, and my graphic card got a HDMI port along with that, in which I can plug in my TV. I done this last night, but it would only let me expand to either 2 moniters, not the 3rd, (i had to disconect a moniter?)

Graphic card is a Ati radeon 4850 HD, with VGA and HDMI ports, 2 VGA's. (one needs a extention to fit but I don't know what this is called)

Do I need another graphic card/or is it just a driver?


Jan 25, 2010
The feature on AMD/ATI cards that allows for use of 3 monitors is called "eyefinity". I don't believe it's available on the 4xxx cards. It was implemented with the 5xxx cards, and you do not need 2 cards to use it. In any case, it requires at least one of your monitors to use a displayport connection. I believe there are some workarounds using "active displayport adapters", but I've heard not-so-good things about them.


The 4850 doesn't support 3 monitors to my knowledge - you would need one of the following options:

1.) Replace the graphics card with one of these options:

AMD Eyefinity: Any HD 57XX, 58XX, 59XX, 67XX, 68XX, or 69XX card with a displayport or mini-displayport (only models with at least 1 displayport type connector) and then an active displayport converter. This is the only way to do 3 monitors on 1 GPU.

nVidia Surround: certain 4XX and 5XX cards (not exactly sure which) can run three monitors in SLI only - so you would need 2x nVidia cards.

2.) Add a USB -> video out dongle - recommended if you don't plan on gaming through the additional output. See these (and similar):


3.) (potentially most difficult/expensive) If you happen to have a motherboard with an onboard video out, you can try getting that to work at the same time. I've had some luck with this on a Z68/LGA1155 chipset with Virtu, but don't know if it will work with other chipsets. Might involve replacing the Mobo to get a Z68, which I wouldn't do unless you really want this or are upgrading anyways.

Hope this helps!



I used 3 monitor eyefinity for over a year on a 5770 through a $30 sapphire displayport->VGA adapter and it worked just fine - performed well in fact. Now I've upgraded to a 6870 (got it cheap) which has mini-displayports...conveinently the exact ports a Macbook Pro has...so I just went over to Best Buy and bought the $25 Best Buy brand mini-dp to vga convert that they sell for people buying MBPs and works like a charm.

When the cards first came out, displayport was new and active adapters were rare and >$100...that's not the case anymore with the Mac adoption of the format (it's also called Thunderbolt).