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MBP 15" connected to Dell U2711 monitor - PCIe malfunction?

21525 Views 33 Replies Latest reply: Aug 1, 2012 1:41 PM by berlindude RSS
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kevinnnnnnn Level 1 Level 1 (0 points)
Currently Being Moderated
Nov 14, 2010 1:56 PM
Hi all,

I bought a new MacBookPro 15" this summer. I also purchased a Dell U2711 monitor and a minidisplayport-to-displayport cable to connect the two. The U2711 is Dell's top monitor with a 2560x1440 resolution.

Here's the deal:
* Connecting the U2711 to my roommate's 2010 MBP 13", everything works flawlessly at maximum resolution. This proves that the monitor and the cable have no problems.
* Connecting the U2711 to my 2010 MBP 15" (everything updated to last version), is a different story. It drives the monitor fine at 1080p (1920x1080), 720p, and a few lower settings. However, when choosing 2560x1440 (or a few less common lower resolutions), there is a very annoying flickering on the screen. After closing the lid of the MBP (which shuts off the screen after 15 seconds or so) and opening again, the flickering is less strong, but still way too annoying to tolerate. (According the a mac store person here in town, closing switches the graphics, which seems to help slightly but not enough.)

I took my MBP to the store, where it drives Apple's large displays without any problem. So my laptop and its displayport aren't broken, either.

What's going on?

Nvidia GeForce 320M, PCI-bus, 256MB, ROM revision 3533, ...etc.
Nvidia GeForce 330M, PCIe-bus, 256MB, ROM revision 3560, ... etc.

On both machines, the monitor is listed identically (DELL U2711, 2560x1440@60Hz, 32bit color, connection type Displayport, etc.).

The relevant difference is that the MBP13 uses PCI, and the MBP15 uses PCIe (or PCI express). I've come across a few hints on the internet that Apple's implementation of PCIe is buggy or problematic.

E.g., this company ( ) makes external graphics cards, and their faq on mac's says:
[ begin quote]
ViDock 3, ViDock 4, and ViDock 4 Plus adapt PCIe cards to an ExpressCard slot. They work with any compliant ExpressCard slot, including the slot in the MacBook Pro. PCIe cards that do not require a large PCIe memory window, such as professional video editing cards and storage controllers, will work with MacBook Pro and ViDock.

However, only MacBook Pro generations 1, 2, and 4 support graphics cards on the PCIe bus provided in its ExpressCard slot. Other generations of MacBook Pro impose limitations on the memory resources allowed to be assigned to PCIe devices in the ExpressCard slot. PCIe graphics cards used in ViDock require more memory resources than are allowed.


ViDocks support any MacBook Pro. The compatibility problem lies on the Apple side. If you insert a VIdeo Editing card, Fire WIre Card or Hard Disk RAID controller card, they will all work in every MacBook Pro. But once you insert a graphics card some MacBook Pro models refuse to grant as much memory to the graphics card as they request. (The reason for mentioned cards all work is because they request so little memory.)

So, if you want to use PCIe cards that do not require a large memory window (PCIe graphics cards require a 256MB window) then ViDock 4 will not work for you. Examples of cards that do work are professional video and audio editing cards (BMD, AJA) and storage interface cards (SATA, 1394).
[end quote]

I'm guessing that maybe this is somehow connected to the problems I'm having?

If anyone has further ideas about this, or has succeeded in running the U2711 at max resolution from a MBP 15", I'd love to hear from you!

I'd also appreciate some response from Apple if anyone there happens across this post: I know your and Dell's small print says you don't guarantee anything when combining hardware like this, but really, it's not a far-fetched combination.



PS I'd rather not downgrade to a MBP13" as I put the larger screen and extra power to good use. I see no use in upgrading to a more powerful MBP.
Also, I like the Dell monitor more than the corresponding Apple screen (cheaper, less glossy, and it has deep color) - if I sold it on the used market and bought a new Apple monitor, that'd set me back $500 or so.

More specs:
Hardware Overview:

Model Name: MacBook Pro
Model Identifier: MacBookPro6,2
Processor Name: Intel Core i5
Processor Speed: 2.4 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache (per core): 256 KB
L3 Cache: 3 MB
Memory: 4 GB
Processor Interconnect Speed: 4.8 GT/s
Boot ROM Version: MBP61.0057.B0C
MacBook Pro 15", Mac OS X (10.6.4)
  • erikstarck Calculating status...
    I have the same setup and the same problems. Also tried with the expensive Dual DVI-converter but that also has problems ("white noise" on screen, not the same flickering).

    I've tried it with two different Macbook Pros, both from 2010, one Core Duo and on i7.

    I'm running a linux box at maximum resolution on the same monitor so it should work.

    Macbook Pro 17, Mac OS X (10.6.4)
  • BSteely Level 5 Level 5 (7,635 points)
    Can you describe what you mean by flickering a little better? Flickering can mean a lot of things. For example, some people that didn't know their MBP had an ambient light sensor said they noticed "flickering" in their screen, which meant in this case the full screen brightness was modulating up and down slightly because the light sensor was detecting differences in the amount of room light.

    There have been other cases where people's whole screen would blink out to full blackness for a brief period, like a fraction of a second, and then come right back on. That was also called "flickering". So a better description would be helpful.
  • BSteely Level 5 Level 5 (7,635 points)
    OK, now I see what flickering means in this case. Kind of a long shot, but does having the power adapter disconnected from the Mac make any difference?

    Also, does in make a difference if you switch to the Intel graphics processor instead of the 330M?
  • KenOnBass Calculating status...

    Did you ever get this resolved? I just took delivery of a U2711 yesterday and am using it with my late '09 MBP 17. I noticed a flicker too when I first plugged it in when the notebook was on, but after I rebooted the MBP for another reason, I didn't notice any flicker all evening and it displayed it's native resolution fine while I had the MBP at 1920x1080.

    MacBook Pro 17" 3 Ghz,, Mac OS X (10.6.1)
  • KenOnBass Level 1 Level 1 (0 points)
    MacBook Pro 17" 3 Ghz,, Mac OS X (10.6.1)
  • KenOnBass Level 1 Level 1 (0 points)
    Sorry that didn't work for you. I changed the power management settings to Graphic performance and it worked fine with two different U2711 monitors. Did you check to see if the power management changes stayed in place or did they revert back to the factory setting? Yes, you want it to run off the PCIe. As a next step, I guess I'd take it to the Mac Store and try it with an ACD 27 and see if the same thing happens.
    MacBook Pro 17" 3 Ghz, 8GB RAM, Mac OS X (10.6.1)
  • TheDuder Calculating status...
    I watched the flicker video above and mine does -not- do that.

    I have been using my MBP 15" (latest version) with the U2711 for ~5 months at full resolution using a mini-Displayport to Displayport cable (no adapter).

    Starting this morning however, after a freeze and hard reboot (holding Power button), the MBP no longer sees the U2711. I tried resetting PRAM and SMC but these didn't correct it. Doing Command+F2 makes the monitor turn the LEDs blue for a bit, but then it re-enters powersave mode.
    MBP 15" i7, iPod Touch 4G
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