iMac completely freezes all the time

What's your point? Does your iMac have a problem?

Looks like a GPU issue. You can try SMC and PRAM reset and also run Disk Utility plus Hardware Test from the install disc.

Looks like a faulty video card. Some models of the aluminum iMacs have a removable video card rather than being integrated with the motherboard. If yours is one then the repair cost would be much less.

If you are no longer under warranty you may want to consider trying to repair yourself (this is by far the cheapest option). Otherwise use a local on site technician or third party computer store that specifically state they work on Macs (buy the part yourself and just ask what they charge to install it, on site techs are usually by the hour). This would be cheaper than the repair through an Apple store.

Since you state that it is 2.0Ghz Core 2 Duo then it is either the 2007 to 2008 model using the ATI Radeon 2400XT or the 2009 model with the nVidia GeForce 9400M. The Radeon 2400XT is replaceable. The GeForce 9400M would require replacing the motherboard.

The best deal I could find on the 2400XT is at Compuvest I have not bought from them before but they have over a thousand positive reviews through Google Products users.

For surprisingly less Gainsaver has the superior Radeon 2600 Pro for the iMac. I am not a 100% sure that you can simply put in the upgraded card. Though I am fairly certain. Perhaps someone can confirm.

If it is the GeForce model it would probably be cheaper to buy a new iMac, transfer your data, wipe the old drive (or keep it for backups), then sell the old iMac on ebay (listed as is for parts or repair).

2009 20" iMac uses 1066MHz DDR3 so it can't be it

basbr said:

I have a problem with my iMac 2 GHz Intel Core 2 Duo (2 GB 667 MHz DDR 2 SDRAM), running OSX 10.6.5.

OSX crashes and freezes all the time. Nothing works anymore. Sometimes it just freezes, and I can only move my cursor, but nothing reacts anymore. Sometimes the screen blacks (or sometimes blanks) out or shows the weird moving colours as shown on the photo I just took below:

After restart, it often happens again and again. Then the iMac is fine for a couple of days, before it freezes again.

Can anyone diagnose the problem from the info above?

Thanks in advance!

Click to expand...

I agree its probably a graphics card issue.

One thing I always do to make sure is back everything up and do a clean install starting from scratch. Probably won't fix it, but it's the first thing I do when I have had a problem.

maybe someting else

your screen shoot looks very very similar to what I had a month ago.I have a 2007 imac that came with leopard 10,5 and last spring I updated to snow leopard.At that point on it become slow leopard for me. then one day it started to crashed and freeze frequently with a screen like yours or a blank screen.After may tests and days with apple specialist they change a memory bar (free of charge ) thinking it would help.24 hrs later it started again. so I did another clean instal without snow leopard and all is fine and fast.
just wanted to let you know.good luck

Either bad hard drive or motherboard

This issue and many other terrible issues plagued OS X, 10.5, in its first few months.

I was an Apple and PC warranty technician, but you say you have OS X, 10.6.

I will ask around with my fellow techs and see what they think. The freezing part, if anything freezes, is usually software related, not hardware related from what I have seen in 12 years on Macs and PCs.

On PCs, it's almost exclusively software related.

If ur screen is messed up like that, it's hardware.
$100 says it's motherboard

biggd said:

If ur screen is messed up like that, it's hardware.
$100 says it's motherboard

Click to expand...

Really? The motherboard issues almost always cause a black screen or unresponsive screen. I know it's possible for hardware to cause weird problems like what the OP has shown, but I have never seen this repairing Macs.

The intermittent issues the OP is talking about is usually not found in most hardware issues. When something "burns" out, it's out. The OP doesn't seem to be saying that it's always blacked out. A more rare hardware condition, assuming blackout is the issue all the time, would be a problem with the LCD itself. Whatever connects the motherboard to the LCD could be out (assuming we are talking about a blacked out screen as the only symptom).

During a time machine issue on many Macs in the first year of OS X, 10.5, if info wasn't flat out lost, sometimes the image on the screen would get seriously botched up not unlike the OP's picture. There is no way to know for sure unless a technician physically sees the machine and tries out a few things.

Post #8 sounds like it has the best reasoning for what is going on, but instead of a faulty 10.5, it appears it's a fault in 10.6, but the main issue is that it was operating system based.

basbr said:

I already tried a clean reinstall, which didn't help. So maybe go back to 10.5 and if that doesn't work, maybe a new one?

Thanks for the help guys.

Click to expand...

You are doing this the correct way. What you have to do is rule out issues one by one and if you feel inclined, write it down.

If it is hardware, which is a small possibility, I would think:

1) LCD (and connection to it)
2) graphics card
3) motherboard

Not sure if this will help but I had a '06 MBP do pretty much the same thing you are getting. The problem there was it would do it when it overheated due to the insides of the computer being so dirty, which eventually killed the computer all together. Install SMC fan control and monitor what the temps are before it freezes. If it turns out thats an issue just leave your fans at max speed to keep things cool. It might not sound the best but def won't harm the computer.

Zach S.

basbr said:

I have a problem with my iMac 2 GHz Intel Core 2 Duo (2 GB 667 MHz DDR 2 SDRAM), running OSX 10.6.5.

OSX crashes and freezes all the time. Nothing works anymore. Sometimes it just freezes, and I can only move my cursor, but nothing reacts anymore. Sometimes the screen blacks (or sometimes blanks) out or shows the weird moving colours as shown on the photo I just took below:

After restart, it often happens again and again. Then the iMac is fine for a couple of days, before it freezes again.

Can anyone diagnose the problem from the info above?

.

Thanks in advance!

Click to expand...

From the symptoms, it sounds like overheating. I have also had damaged video cards do similar thing

Your problem sounds like a different flavor of what I've been experiencing. Below is a recent screenshot. The problem is very intermittent for me. Invariably, everything goes back to normal (for a while) after a reboot. I just ran the Apple Hardware Test and everything came back normal so I have no idea what the problem is. Anyone have a clue? I may have to go through the trouble of a wipe and reinstall which is a real pain.

[/IMG]

flipangle said:

Your problem sounds like a different flavor of what I've been experiencing. Below is a recent screenshot. The problem is very intermittent for me. Invariably, everything goes back to normal (for a while) after a reboot. I just ran the Apple Hardware Test and everything came back normal so I have no idea what the problem is. Anyone have a clue? I may have to go through the trouble of a wipe and reinstall which is a real pain.

[/IMG]

Click to expand...

Hi, I have been having the exact problem as this.
I have tried everything, reinstall OSX, delete all data off HD.
An Apple Genius Bar techo told me it's either the graphics card or logic board.
They quoted me $1000.00 approx to fix.
Have you had any luck with your Mac?
Would love to know if you were able to sort it out.
Cheers

I just finished a clean install. Will let you know. Does not look promising though since I did experience a similar problem after the install. It did not lock up the iMac and lasted for only less than a second.

The clean install didn't work. Same problem as before.

63dot said:

Really? The motherboard issues almost always cause a black screen or unresponsive screen. I know it's possible for hardware to cause weird problems like what the OP has shown, but I have never seen this repairing Macs.

Click to expand...

My mistake, I'm used to PC's with integrated graphics. You are correct, graphics card.