Red and green square dots?

after reading the latest entires here, while I still believe this is mostly hardware related, I'm skeptical about firmware and OS, hear me out: I'm *mostly* glitch-free when I don't open a web browser app. What browsers is everyone running on the Mavericks platform right now?

I did a complete erase and reinstall and was having the issue when I'd open a Finder window. As soon as I booted to Mountain Lion on an external I didn't have any issues in the Finder or using Safari. My next test will be installing Chrome and iPhoto on the external to see if those cause the pixel anomalies, since I noticed it in Mavericks the most with those two applications.

dude, I just transfered my Chrome and iphoto .apps over to my secondary internal storage drive. Couldn't move Safari, the OS wouldn't let me. Repaired disk permissions and restarted...

So far so good, and when I say that I mean no hard freezing/major glitches. Some light intermitent yellow pixels flashing, but nothing like what it's been. More to report later... rotten apples in 2010...

So the uninstall Chrome fix only last 1 day, on the second day after 4 hours working with final cut pro 7 the problem came back, I restart and was able to work for 2 more hours, since then it only takes about 3 to 5 minutes to hard freez again, it's so anoying and here in Mexico we don't have Apple Stores only apple authorized service providers and for what I see there is absolute no warranty that changing the video card will solve the problem, so basically my imac is an iPaperweight now.

Uh, yeah, I second what Alejandro is saying. Doesn't matter what drive your apps are on, the problem persists. My freezing came back after 20 minutes of migrating problematic apps to other drives.

Never buying an iMac again, why have one custom built for 8-15 years of high-end use when it fails you in 4.

Yeah, just like Soul said, running the OS on an external drive doesn't help. The green pixels don't appear as much using Mountain Lion on the external drive compared to running Mavericks on the internal. With the internal drive the green pixels stay on the screen for days of uptime, where as on the external they only appear for the first few minutes of the iMac being turned on.

I'm thinking the issue does have something to do with the Radeon 5750 starting to go out. I took my iMac apart today and did the oven baking trick to reflow the card, along with adding new thermal paste to the GPU and have been running smooth all afternoon with no issues. I'm hoping that I caught the card early enough and won't have any further issues, but I'll update if the pixel issues come back.

...uh, dude. so where is the oven bake trick described in detail?

I agree that this will most likely be the last iMac I own. This is my second one in 5 years. This one being a replacement for the one I bought in 2009, no one could figure what was wrong with that one either. I had a cheap Dell laptop that I dropped a couple of times and it lasted longer than these have. :\ What bothers me the most is that there doesn't seem to be a clear fix, not yet anyway.

I should note that I was previously running Snow Leopard, and I recently upgraded to Mavericks... my problems are 10x worse now. I'm not sure why upgrading to Mavericks made it worse, but it did. The flashing blocks are much more frequent, and now my iMac has decided to randomly start freezing and restarting. All this after the Apple store told me "their programs couldn't replicate their issue".

Cool.

Today I go back the Apple store to look at it again after they put in a new graphics card a month ago. They just can't accept that they Apple messed up the mid 2010 iMacs. My 2011 has no issues what so ever. Apple really needs to be held accountable for faulty system which has no answers. I still have a MacBook 13 inch from 2002 with no issues.

The topic of baking in some goodness by oven cooking the graphics card

had been discussed, & searchable via google or other online method....

Essentially the card is placed on a cookie sheet held above the metal flat

with small balls of aluminum foil holding the corners of the graphic card

so it does not contact direct to the cookie sheet and air, about solder melt

temperature (325°F +/-) can circulate around it. There are pictures on some

of the better uploaded topic discussions.

•iMac bake graphics card in oven - search results:

https://www.google.com/search?hl=en&source=hp&q=iMac+bake+graphics+card+in+oven

{When I replied earlier, someone didn't like my suggestion to double

the joy by putting in a cookie sheet with actual cookies on it, so

that post was deleted. After you've done the search and see what I

mean, then come back and bake your graphics processing card.}

Baking Apples has been an answer, especially some iBook G4s.

However a qualified specialist with modern workstation could do

it for less than the cost of a new graphic card, if you ship it away.

I've done micro repairs in the past, both electrical & metalsmithy.

But don't waste the heat, if you've got nothing to eat; you are in the kitchen.

Good luck & happy computing! 🙂

K Shaffer wrote:

The topic of baking in some goodness by oven cooking the graphics card

had been discussed, & searchable via google or other online method....

Good luck & happy computing! 🙂

niiiice. Maybe this summer I'll bake my GPU see if it helps.

But before I break out the easy bake oven, what if my GPU works fine when in TDM? Should I bake my logic board then?

Not sure if that one should be on the top rack or bottom,

since Target Disk Mode is a very limited aspect of OS X

and does not represent an adequate test of the Graphics.

Oh, be sure to bake those cookies first while warming

the oven, and double-check any temperatures.

While there are some ideas on baking graphic cards,

I did not look into the iMac logic board receipes yet.

This summer, depending on how things work out, you

could just set the whole works in the barbeque... LOL

Neighbors may see the smoke & set-off an alarm, tho.

Life is too precious to take it serious.

Good luck & happy computing! 🙂

Quick update on my 2010 27" iMac... Genius Bar took it for repair, intending to replace the graphics card. However, they saw that I had an Apple Certified tech install a third-party SSD. They complained that the SSD was too close to the graphics card, which could be causing my problem. So, I took it back to the Apple Certified tech who checked it. He said that the SSD is exactly where it is supposed to be. But he took it apart, cleaned it out and put it back together. He ran all the diagnostics and tested it for 24 hours and couldn't reproduce the problems I've been experiencing. As soon as I booted up the iMac at home, the screen distortion apppeared. I've been having trouble ever since.

I'm super frustrated.

I know that some have had success using the defective iMac as a secondary display for another computer.

Has anyone tried using connecting a monitor to the defective iMac? If so, does the graphics distoration (as well as freezes) occur when using a connected display?

My mid-2010 27" iMac has been experiencing similar "shimmering" or "dancing" pixel - mostly, in the morning after mysterious over-night restarts of an unknown origin.

Mavericks (latest iteration - 10.9.2 - which wreaked considerable havoc, initially) - Chrome as primary browser.

Concerned that my display may be failing, I first ran Apple's Disk Utility to repair permissions on the internal 2Gb Seagate hard drive, and "voilå" - shimmering vanishes!

This morning, the only repairs effected were:

Group differs on “Library/Printers/InstalledPrinters.plist”; should be 80; group is 0. Permissions differ on “Library/Printers/InstalledPrinters.plist”; should be -rw-rw-rw- ; they are -rw-r--r-- . Repaired “Library/Printers/InstalledPrinters.plist"

Have absolutely NO idea why running Disk Utility resolves this issue, but it seems to - each and every time: Should I take comfort from the thought that it's NOT a hardware issue, or might this simply be a false hope on my part?

These issues - the occasional freezing, overnight self-restarts, and shimmering pixels - have only seemed to appear post-Mavericks: Anything to that, or mere coincidence?

Thanks!