Mac mini 2010 / flickering display on Samsung 206BW

By doing more search, it seems many people are experiencing flickering problem with the mac mini (varies from monitor vendor, Samsung’s are reported to work bad with the mini). A workaround with previous minis (without HDMI) was to connect to the monitor using VGA (through mini DVI to VGA adapter)… Replacing the mac mini/motherboard many times didn’t work for these people, so they are implying the problem comes from Apple’s driver software (and thus could/should be fixed in a later update). Here are a few useful links (among many other) I found :

http://forums.macrumors.com/showthread.php?t=989930

http://www.ehmac.ca/mac-ipod-help-troubleshooting/80230-flickering-mac-mini-lcd. html

The Samsung 206BW doesn’t seem to allow refresh rate above 60hz at 1680×1050, however some have had good result (with other monitors) using 58 or 57hz (using a third party utility).
I tested lower resolutions through Apple’s monitors preferences pane, and some provide additional refresh rates (70 and/or 75hz) : for most, switching the refresh rate higher didn’t fix the flickering issue. Moreover, the 1024×768 resolution didn’t experience flickering, even at 60hz, while the “1024×768 (stretched)” (in fact both modes display stretched image) did flicker whatever refresh rate !

Message was edited by: cjed

As some users had less flickering connecting the monitor through VGA, I bought the Apple mini display port to VGA adapter, and here are the results :
-the flickering seems gone (at least very slight), particularly on gray tones where the problem was huge.
-however the image now has a pink tint (on white), and colors (white) are oversaturated (no mean to fix this through ColorSynch settings nor monitor's settings).
-the text and controls borders are less sharp.

Then it isn't really usable, and I'm stick with DVI and flickering (that at least mainly occurs on gray colors, hopefully not the most used).

Will Apple provide soon an update to GeForce 320M chipset driver, as it is likely to be a software problem ?

Message was edited by: cjed

Message was edited by: cjed

Thanks BSteely, you are right about the 206BW doing dithering to achieve 8-bit colors, so it could explain the poor quality in VGA. I would have to check with my projector (also through VGA) whether it is the same.

About the flickering with HDMI to DVI connection, since the Snow Leopard Graphics update it is still here in GarageBand, however it doesn't show anymore on the gray background of my web site, so it seems rendering has been improved in Safari, really strange (I would expect same behavior in all applications).

I also checked pluging the monitor to a 2-pin connector (instead of 3-pin), in case of a ground loop (mac mini being 2-pin now). However it didn't help (and I would have - did - go back to 3-pin connection for the monitor whatever result, for safety reason).

Then I really think it has to do with software (or at least could be fixed through a driver firmware update).

Message was edited by: cjed

Message was edited by: cjed

Message was edited by: cjed

Yes, dithering could explain why it happens on some grays and not on other (some gray colors are known to reveal poor quality of LCD screens, through inversion test), however the flickering appears mostly for dark gray areas.
Moreover since the graphics update, at least one of the gray colors that experienced the problem doesn't anymore, while others (those grays in GarageBand) still do.
I then think the digital video output of the mac mini (320M chipset) is less stable than my old dedicated video card (Radeon 9000 Pro), that worked fine on the same monitor in DVI. And the graphics update may have enhanced a little the output stability.
It may also be a power unit default in the mac mini.

A monitors compatibility list would be nice for the mac mini, as it seems it has been experiencing compatibility problems for years. A test software from Apple may allow to check for the chipset (in case of an hardware default), as they did for previous Nvidia 8800 in Mbp.

The 10.6.7 update didn't fix grays flickering.

Moreover, using Apple's mini display port to DVI adapter (instead od HDMI to DVI adapter) didn't solve the problem either.

Apple really should work on this, or provide some tools to check hardware (it is the same with stock 2*1 Gb memory, or third-party 2*2Gb, 2*4Gb).

Message was edited by: cjed