ATI Radeon HD 5770 Graphics Upgrade Kit for Mac

Since each 30" has a DVI conector you can plug one into the 5770's DVI port. For the other 30" however you are going to need a mini displayport to dual link DVI adapter. Apple sells this one. But you can get a cheaper one from monoprice.com.

Note the above answer was for the question you shouted out in bold. But then I read your "fine print". Adding a third monitor (TV is just a monitor) to the card adds some wrinkles to the mix. When 3 monitors are to be used on 5x70 cards you should be aware of the information in these apple docs:

Mac Pro (Mid 2010), Mac Pro (Early 2009): Issues with three displays and multiple DVI, HDMI connections

Mac Pro (Early 2009), Mac Pro (Mid 2010): Supported display configurations

Basically what it comes down to is that there isn't enough power on the card to drive 3 monitors unless two of the ports have active adapters. So what it comes down to is how much your budget will allow for the various possibilites of juggling the three ports and possible adapters. While there are plenty of mini displayport to HDMI adapters to be had (e.g., monoprice's) they are not active adapters.

Previous reply continued -- I hate that 15 minute timeout these forums have, can't even complete one post as in this case.

One immediate setup that comes to mind is that you connect the two 30's to both your mini-displayports using two of those adapters I mentioned earlier. Then connect the DVI port to one of these:

DVI & S/PDIF Digital Coax/Optical Toslink Audio to HDMI® Converter

Also connect the optical out to that box. The box will combine the audio and video and pass it to your TV via an HDMI connection. In this setup everything is an active "adapter" so I would think it has to work. May not be the cheapest set up (two dual link adapters and the box) but it's the most obvious to me as I am typing this.

FWIW I use one of those boxes. It counts as one of my active adapters and I have a mini-displayport to VGA adapter which counts as a second "active" adapter. The remaining mini-displayport is connected to my 27" apple display.

One final thing. If you do end up attaching the two 30"s and the TV, no matter how you end up doing it, you should consider using SwitchResX to allow you to change monitor configurations via hot keys or menus. For example, you might not want to use your TV on your computer all the time. SwitchRexX can allow you to "disconnect" it from your computer without having to pull cables so you can use your TV as a normal TV.

So, if I understand well, I need two adapters dual link DVI for the two 30" monitors to plug them to the 2 mini display port of the ATI 5770.

For the max resolution of a 30" display with a dvi connection you need dual link. So with 2 30"s connected to the mini displayports you of course need two of then. Note that the additional power is supplied by USB (that's why there are 2 leads on that adapter).

Note, I don't know how much USB power these converters suck so the only wild card in this scheme is what effect they would have on the USB ports with respect to any other stuff you might be haning off of USB. If you have too many other USB connections you may require a powered hub. There's no way of predicting this until you actually try the setup (at least I don't know one).

Then, since for the TV LED 40" I have already a HDMI - DVI cable, which adapter( active "adapter") /box you suggest to connect to the DVI port of the ATI 5770 ?

For that box you need a DVI-D (or I) cable. There's actually one shown at the bottom of that monoprice page I referenced. That picture references this cable but any similar cable will do.

Note I suggest that box to allow you to pass a single HDMI cable to your TV which of course carries both video and audio. Instead of using the box you could still use your DVI to HDMI cable. But you would then need to come up with an additional connection for the audio since DVI doesn't pass audio. You could go analog audio out of your computer (using the mini jack) and connect that to your TV's analog audio in. Or if your TV actually supports TOSLINK (optical) in you could directly connect that from your computer's TOSLINK output.

I've been assuming that you want to use your TV to stream video with audio. If you only intend to use the TV as a third computer monitor, then screw the audio and just use that DVI to HDMI cable you already have.

Like I originally said in my first reply post, there are various combinations of alternatives dictated by how much you want to pay and the possible combinations of adapters needed to handle the connections and simultaneously satisfy the requirement of at least two active adapters for three connections to a 5x70.