Friday, December 11, 2009

My transiently flickering i5 iMac and notes on academic store purchases

After an unusually prolonged period of weakness I bought a 27-inch Core i5 iMac. It's a lot of money, but we've had a moderate need for a new machine for some time.

I purchased it through the UMN apple store (I'm adjunct faculty) so I got $100 off but paid taxes (MN needs the money). The alternative is Amazon, where the final price is a bit lower (no taxes, free shipping) but there's a higher risk of shipping damage, a longer wait, and the modest hassle of pickup.

It's been a while since I bought at the UMN store. One things I'd forgotten is that it only looks like an Apple store -- it's a separate business. They don't allow any returns at all after something is opened (!) and they don't have access to all of Apple's bulletins and internal documents. Their mildly discounted AppleCare came with $100 off an iPod, but we already have a lot of iPods so we passed on it. My AMEX card doubles the standard 1 year warranty.

The store was selling Crucial memory for $180 (w/ discount), the same memory from Crucial is $114. I passed, the machine has 4GB. I'll get more after it's settled in. The Apple mini-display port to DVI adapter cable costs $30 and lacks analog pass through, Amazon currently has one for $8 (plus shipping!) with decent reviews and a full set of pins.

I'm sure I'll run into bugs. Here are the first three ...
  1. After a restart it seemed to have trouble finding the bluetooth mouse. It put up a warning note but it found it a few seconds later. I gather this is a known glitch.
  2. When I went to show the machine to Emily the screen saver started to stutter! I was going to tell her how trouble free things had been. It hasn't done this since, but there are known problems...
  3. There's an old glitch with MobileMe registration that probably impacts me and five other people.
The MobileMe glitch hits people who have "" Apple accounts and MobileMe accounts that didn't migrate from the original .Mac account. It's not an unexpected glitch -- Apple has trouble with the five of us. It's easy for a geek to work around and only a geek would ever be in this odd situation.

The packing and unpacking really is a zen experience. There's one cord on this machine, and that goes to the wall socket. The screen doesn't feel big to me, I can get used to big screens very quickly.

I'll update this post or add new ones if I find any more surprises.

Update: An unofficial site claims Apple is replacing the video card and holding shipment. If I'd caught wind of this one I would have waited until the end of January. I'll go slow on making this a primary machine until we find out if it will need to go for repairs or replacement. It's quite heavy to move!

Update: After a few hours of running a network accessed slide show we saw one episode of severe flickering and another of stuttered image display. So I have the video problem. I strongly recommend holding off purchases of this machine. My serial number is W8946HAH5PJ (emphases mine), that would mean it was manufactured in week 46.

Update 12/13/09: It is a weird problem, but I can't believe Apple hasn't known about it for weeks. I wonder if this is why none of the three local Apple outlets had an i5 on the floor. The flickering video would get quite a bit of attention! The issue has started to get trade pub attention, so I hope we'll get an Apple response this week.

My particular machine passes all hardware tests, and I did the never-useful PRAM reset thing, but it still shows up during my screen saver photo slideshows (images are on a server, network is 802.11n). I called Apple Care just to create a tracking number for my machine problem, but I didn't ask for a replacement.

Most recently, I'm finding that after an hour or two (on average) the zoom and pan transitions will start to stutter, with occasional violent jerks. If I move the mouse the screen is fine again. I haven't had this occur except during the screen saver shows because I've made so little use of the new machine. I'm reluctant to move it into production use since there's a good chance I'll have to return it in the next week or so - which will mean a full reinstall.

I'm betting this is a hardware defect and it will require a recall or a firmware "fix". I wouldn't be shocked if there were problems in more than one hardware component.

Sigh. I know better than to buy a new Apple machine. I was weak, and I'm only getting what I deserve.

Update 12/13/09b: Saw this post on how a tech fixed his own machine. It hints at what to look for if there's a recall ...
Apple suggests ...
1. Verify if it occurs with an external display too. If it does (see separate chart)
2. Check all four cables for being damaged, pinched, etc...
3. If it still occurs shine bright (low heat) flashlight into front of LCD. Verify if an image is being displayed when flickering issue is occurring. If so, replace vertical sync cable (between LCD panel and upper end of LED backlight board) and retest.
If issue persists, replace LED backlight board.

If not, replace internal DisplayPort cable (between logic board and LCD panel), and retest.

For horizontal lines it says:
1. boot from dvd and see if it still does it, if not, it is a software issue
2. if it does still do it, check external display, if it does it there it is not the lcd, but could be the video card.
3. If video card is replaced and reseated and it still happens
4. Check ram by using only one module and testing with another available module.
5. If it still happens replace logic board.
Update 12/16/09: A relatively technical post from the PC World about flickering and the i5's graphics card. Reading the Apple Discussion threads it feels like there are more than one set of problems going on.

Update 12/21/09: Apple has a graphics card firmware update out for the ATI Radeon HD 4670 and 4850. Some machines may have the updated firmware: " You should see revision 113-B9110C-425 or 113-B8030F-260 if the update has been successfully applied." Apple is also busy deleting posts from the original discussion thread -- I wonder if the entire thread will disappear. Some of the deleted posts reported the firmware update reduced GPU clock speed and heat -- so it seems the update might reduce GPU performance.

Others have already reported the update did not fix their display issues.

This smells like a fragile graphics infrastructure prone to multiple pathologies leading to flicker and image mangling. It may take several different fixes to clean up the mess.

My own display flickering resolved a week ago without applying any update after I moved my i5. The only changes were a new outlet, very close proximity to my 802.11n router, and possibly a cooler room (but not much cooler).

Patrik Montgomery

... There seems to be at least two different defects. One is a software thing that the firmware update is supposed to fix, and another is the display cable coming loose internally - possibly during transfer, which is why the problem seems to be more common with CTO machines.

The software defect seems to be something in the settings getting corrupted. A PRAM reset can correct this, but if the defect is still there, it might happen again at any point. The firmware update is there to correct this defect, so a firmware update + PRAM reset can be a permanent fix. One big gotcha is that the wireless keyboard apparently cannot reset PRAM reliably, so you may need to do it with a wired keyboard. A Windows keyboard works fine, if you don't have a wired Mac keyboard - just hold the Windows key instead of Command and left Alt instead of option (so Windows-left Alt-P-R).

Update 1/21/2010: I've not seen any flickering since the first 1-2 days of use. I did move it upstairs. Maybe a loose cable moved into alignment?

Update 2/2/10: MacFixit has a good discussion of the state of the fix after the 2nd firmware update. The newest update aims at the mysterious chip, not the graphics card, that controls the display, which I'm impressed they can update. Since this feels like a multi-factorial problem, this would leave people suffering from a loose cable that moves around when the case is moved. MacFixit suggest PRAM and SMC resets be applied after the firmware updates.

Update 2/24/2010: No flickering - so I never had any more after that two-three days of use. I wonder if a cable had shifted when I moved it around. I checked the Apple forum flicker thread -- Apple had to lock it on page 300 because browsers were choking. They hit some kind of forum software maximum. Apple opened a new thread to continue the complaints. I've never seen them be so accepting of unhappy customer posts. The second firmware update, the one that worked on the display chip, did seem to help many.
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