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multiple monitors & screen resolution

M

Maxi86

macrumors regular
Original poster
Sep 24, 2010
174
0
I've connected a secondary monitor to my 27" iMac...
It's a Dell 29" monitor (I don't have the product name). I connected the two monitors using a mini-displayport-to-DVI connector. I would have chosen for HDMI, but the Dell monitor lacked that unfortunately.

I've installed Windows 7 on a BootCamp partition, and I happened to be in Windows when I did this. When I turned it on, it was a duplicate display of my iMac screen. Same resolution.

I went to control panel and screen resolution, and chose for 'extend these displays', but suddenly the resolution on the Dell went from 2560 x 1440 (like the iMac) to a max of 1280 x 800... which is also recommended by Windows...
But I would really like to choose an higher resolution.

Does anybody know whether it's possible? Would it matter if I go to Mac OS X?
 
I have the same issue with a 30" Apple Cinema Display running off of my late 2009 MBP. In OS X everything is fine, both run at their best resolutions, I can close the MBP lid and just use the Cinema Display, etc.

I've just installed Windows 7 Home Premium 64-bit in boot camp, and if I have both monitors on, they just mirror.. and I can't close the MBP lid.
 
It's a 30" Dell 3007WFP-HC... I think it's one and an half years old.
btw in Mac OS X, it doesn't matter whether it's mirrored or side by side, max resolution stays 1280 x 800
 
I'm using a mini-displayport-to-DVI cable...
it's all I can use with my iMac :(
 
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So you'll have to live with 1280x800. Which is exactly half the native DPI of the display. 4 native pixels used per pixel at that resolution.

B
 
Maxi86 said:
I'm using a mini-displayport-to-DVI cable...
it's all I can use with my iMac :(
Click to expand...

What you need is a mini DisplayPort to DualLink DVI cable. Only these will give you the native resolution of 2560x1600 of your screen.
And yes, you can use it with your iMac as well!
 
thanks guys... I will order one..
damn, that means by current cable will be worthless...

EDIT:
btw why is the Apple one pretty lousy?
 
You'd see the same behavior if you were using an Apple 30" display with a cheap DisplayPort to DVI adapter.

Resolutions over 1920x1200 *NEED* a dual-link DVI (or native DisplayPort) connection. The monitor doesn't have HDMI because HDMI doesn't support the native resolution. (Note: The very-latest revision of HDMI - the one that supports 3D - is theoretically capable of that resolution, too; so far, I've only seen it on devices advertising 3D, not on higher resolution devices.)

The trick is that the DisplayPort-to-DVI adapter you have, along with all DisplayPort to VGA adapters, doesn't actually "convert" DisplayPort to DVI (or VGA,) but rather is purely a "physical adapter" that changes one physical port into another without doing anything electrically. Because DisplayPort has enough physical pins to pass a single-link DVI (or VGA) signal, there is just a sense wire that detects that you have the appropriate adapter, and the video card itself changes from sending a DisplayPort signal to sending a DVI signal.

In order to display more-than-1920x1200, you can't just use one of those physical-only adapters. You have to use the native DisplayPort signal coming out of the video card. And if your monitor doesn't have a DisplayPort (too bad, Dell was one of the earliest adopters, all of their current 30" displays have a DisplayPort connection,) then you have to resort to the expensive DisplayPort-to-Dual-Link-DVI active adapters. These have a signal translator that takes the DisplayPort output and actively converts it to Dual Link DVI.

Every 30" display I've seen, if you only use a single-link DVI cable, declares itself a 1280x800 display. As balamw says, exactly 1/2 resolution each direction.
 
thanks for the great explanation...
btw first I was thinking of getting a new monitor, I was considering the Dell UltraSharp U2711... which has a lot connection options, like HDMI and DisplayPort...

in that case what would be the best way to connect it to an iMac?
 
balamw said:
Since the Apple one seems to be pretty lousy, you may just want to try this first:
http://www.monoprice.com/products/p...=10428&cs_id=1042802&p_id=6904&seq=1&format=2

B
Click to expand...

I ordered this one, gonna try it out before thinking of getting a new monitor :p...
I had to pay more than $25 for shipping to the Netherlands, which is a bummer. But here I couldn't find any other than the Apple one.
I hope the shipping won't take too long. I'll let u guys know when it arrives...
 
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