Need 1366x768 Resolution for 2nd display (50" Plasma) HOW??

[Altimeter88]

I have a Mac Pro with the X1900XT video card. Looking at the back of the Mac I have a Dell 2405FPW hooked to the right-side DVI port and my VIZIO 50" Plasma hooked to the left-side DVI port with a DVI to HDMI cable.
I do get a great picture and everything seems to be fine except there is no resolution option for 1366x768. Now this is not anyting new, most video cards are not capable of this resolution because the 1366 is not divisible by 8bits but most cards (including the Xbox 360 via RGB) allows 1360x768 which looks great and is the best option. Right now I have it set to 1280x720 which is displayed with about a 2" border around the screen.

So if anyone has any ideas on how to get the Mac Pro to output 1366x768 or 1360x768 as a second display on the X1900 that would be great.

 

[AppliedVisual]

1360/1366x768 are standard VESA and TIA resolutions and AFAIK should be supported by the Mac Pro with that video card. I can output these resolutions out of a G5 quad w/nVidia 7800GT video card *IF* the connected display lists them as part of the supported resolution list.

However, notice the *IF* there's a good bet that the Vizio display does not actually support an input signal in its native resolution! Sadly, most LCD and Plasma TVs on the market do not accept native resolution input, they tend to only support ATSC HDTV standard input resolutions. Meaning that you're stuck with 1280x720p or 1920x1080i and the image either gets scaled up or down depending on which res you're running at and what your overscan settings are.

Check out the LCD and Plasma forum over at avsforums.com and do a search there. Chances are you'll locate your answer and I bet it's just a lack of support for such an input resolution. You could always try a config file hack/mod to add the desired resolution to the standard list on your system, but I seriously doubt this TV will support it as an input.

 

[Spanky Deluxe]

Try downloading SwitchRes to add custom resolutions to OS X and give that a try.

 

[Altimeter88]

Try downloading SwitchRes to add custom resolutions to OS X and give that a try.

OK well I tried SwitchResX but couldn't get it to work. I would put in a custom res or try to add it to the menu but it never change the res.
I will look over the manual because it seems like I just must be doing something wrong. Thanks though for the response.

 

[MRU]

I have a similar problem to you. Oh and I couldnt get switch res to work either.

My macbook is in my bedroom with my 42" LCD (a big bedroom ) and its res is also 1366x768.. but the macbook only ever outputs 1280x768 and as we all know monitors prefer to be run at their default res... it annoys me that I cant set it.

I plugged in my cousins dell laptop and it does output 1366x768 on the external tv. so is this a mac thing ?