Q: New iMac 27inch screen flickering/tearing/shutoff

pazuita wrote:
Warren........"So it sounds like you are saying that even though the Mac Pro has an older card than the high-end i7 iMac with the ATI Radeon HD 4850, the Mac Pro with the Nvidia GeForce GT 120 card may actually provide better graphic performance because it is a faster machine, correct?"

Yes, basically.

The high end Mac Pro's will still outperform the i7, even with the older graphics cards. The i7 iMac does however hold it's own against the low end Mac Pro's. It won't be long before the Mac Pro's have another upgrade that will most certainly blow the socks off of the iMac. That upgrade will not be limited to the cpu, but will undoubtedly contain a significant upgrade of the graphics card as well.
The Mac Pro's use the full size graphics card, while I believe the iMac is still limited to the mobile version. Smaller means more heat, and lower performance, so an older, slower card in the Mac Pro has a head start.

I believe Schwa72 is correct in that the 4850 is just not enough card for the i7, obviously, it may not be enough for the high resolution 27" screen.

If I wanted to bet on a new rumor regarding the next revision, it would be that Apple will soon offer the i7 with the option of either an upgraded ATI, or NVIDIA card.

As for the benefits of changing the resolution of your screen, I don't know if that would extend the life, but it will make things easier to read, since lowering the resolution increases the size of on screen objects.

Heck, it would even make it easier to see that you left an i out of NVIDIA. (that spelling, by the way is used just about as often as NVIDA all over the net, googling either spelling will get you to the same places)

Whether or not one computer will "outperform" another completely depends on the context of the comparison. With 3D-graphics-intensive tasks, computer performance is completely bound by the GPU. In other words, for 3D-graphics-intensive tasks, the iMacs will absolutely outperform any Mac Pro with a lesser graphics card. If a program is GPU-bound, it makes no difference what CPU is powering it, it'll still be slower than a computer with a better GPU (and a CPU that's able to keep up with that better GPU). This is shown time and time again in gaming circles when folks wonder why their Core i7 monster overclocked to 4.2GHz can't cut the mustard with a single 8800 GTX GPU.

Bottom line -- if a program is GPU bound, there is NO WAY you can compensate for poor graphics performance by throwing a more powerful CPU into the mix. Anyone who tells you otherwise simply doesn't know what they're talking about. However, if you're running Word, compiling a program, or doing other CPU-intensive tasks, then the Mac Pro with the crappy GPU will be faster because the GPU isn't being used.

You can already get a graphics card for the Mac Pro that will blow the pants off of the HD 4850 -- the NVIDIA GTX 285. This card has actually been available for quite some time.

BTW, if I Google "nvida," what I get!

HELLO everybody

since 1 month I set on the "use interference robustness" of my air port EXTREME (the one which connects my iMac to internet) and didn't experience screen flickering problems anymore!!!!

Is that the solution?

thanks

Warren Beasley wrote:

pazuita wrote:
If I wanted to bet on a new rumor regarding the next revision, it would be that Apple will soon offer the i7 with the option of either an upgraded ATI, or NVIDIA card.

Well, you know, it seems to me that if the current problems are eventually revealed to be directly related to the HD 4850 card not being strong enough in the i7's, then it seems to me that the fair and honest thing to do would be to put a better card in the first revision of the i7.

In other words, the better card shouldn't be an upgrade option; the better card should be part of the default configuration of the next generation of i7's. After all, if Apple put a problematic graphics card in their machines which is causing these problems, why should dedicated Mac users have to dish out more money to get rid of the problem? Apple created the problem, not us.

Sure, there can be an upgrade path for the i7 graphics card, but it shouldn't for an upgrade from the HD 4850 to something better, but rather, for something better that is already in the first revision i7's, to something even better still.

Do you follow me?

Of course, this is all just speculation...in case someone is listening.

iMacs simply were not designed to be gaming machines. There is no mobile GPU on the market that would satisfactorily drive a 2560x1440 display at maximum game settings and be able to maintain 60fps. If you accept that the iMac isn't a pure gaming machine, then the HD 4850 is completely adequate.

Problems aren't going to arise because the HD 4850 "isn't strong enough" for the i7...it's just that performance in certain 3D applications will be hindered by the HD 4850 when the i7 is capable of driving a more powerful GPU. For those apps that don't require much GPU power (like video encoding, for example), the i7 will really be able to stretch its legs.

Seriously, if you're not a big-time gamer, the HD 4850 is more than adequate. The graphics cards in my gaming rig alone cost $1400. I don't think anyone would want to pay that kind of premium for superior graphics performance in their iMac. Besides, I have two power supplies in my gaming rig totaling 1450 watts to support the hardware I'm running. That's an unrealistic power requirement for the iMac. Even a single powerful desktop GPU (like, say a GTX 285 or one of the new 5800-series ATI cards) would require too much juice for the iMac's ~300 watt power supply to provide...not to mention the significant expense of high wattage PSUs...

Thanks Schwa72 and Pazuita for your additional comments. I am finding them quite educational.

Personally, I am not one of those big-time gamers. About the only game I ever play anymore is Scrabble, and that is when my brain is too tired to work...and Scrabble most certainly is not a GPU-sucking game. Not even Monopoly is for that matter, I suppose.

I do occasional Photoshop work, and a bit of video re-encoding now and then, but other than that, probably the most intensive thing I do on my current machine is watch videos. The rest is small stuff, like write and respond to email, surf the web, download a YouTube video now and then, use BBEdit a lot, respond to BBS messages, download software, etc.

But my concern is that the issues being discussed here do not just reveal themselves when folks are playing some of those big, memory-hogging, CPU-busting, 3D games. Many folks have reported experiencing problems shortly after turning on their machines.

This seems to indicate that intensive use of the machine is not necessary in order for these problems to occur.

Schwa72 wrote:
Even a single powerful desktop GPU (like, say a GTX 285 or one of the new 5800-series ATI cards) would require too much juice for the iMac's ~300 watt power supply to provide...not to mention the significant expense of high wattage PSUs...

Interesting...So you seem to be suggesting that even if Apple were to decide to put a better card in the first revision of the i7 iMacs, it won't be by much...maybe the HD 4870, you think?

Message was edited by: Warren Beasley

Warren Beasley wrote:

Schwa72 wrote:
Even a single powerful desktop GPU (like, say a GTX 285 or one of the new 5800-series ATI cards) would require too much juice for the iMac's ~300 watt power supply to provide...not to mention the significant expense of high wattage PSUs...

Interesting...So you seem to be suggesting that even if Apple were to decide to put a better card in the first revision of the i7 iMacs, it won't be by much...maybe the HD 4870, you think?

Message was edited by: Warren Beasley

According to AMD's website, the best notebook-class card that's available right now is the HD 4870. NVIDIA's best mobile part is the GTX 280M which is roughly equivalent to an underclocked GTS 250 desktop card, which is really a rebadged 9800 GTX+, which, in turn, is basically an 8800 GTX (NVIDIA's been doing a lot of rebadging lately).

I honestly don't see how Apple could use anything other than a notebook part for the iMac if they intend for it to be a svelte all-in-one system. So, even if they went with the GTX 280M (which I'd be willing to bet that they won't), you wouldn't gain much performance over the HD 4850 (Google "4850 vs. 9800+" for some benchmarks). At best, you might get around a 20% performance boost with the GTX 280M vs. the HD 4850. The bottom line is that, right now, the HD 4850 is in the top tier of notebook graphics cards.

I personally wouldn't even attempt to build a 2560x1440 gaming machine around any current single GPU solution (the HD 5870 might cut it, but it'd be close), desktop or otherwise. In my opinion, no existing single GPU desktop card is sufficient to drive a monitor like the iMacs for gaming -- never mind notebook cards. The HD 4850 is about as good as it gets for notebook cards right now; I suspect you wouldn't even "feel" the difference with an HD 4870 because it'd still be inadequate for serious gaming but more than enough (as the HD 4850 is) for everything else.

This is just sad. People (in good faith) making excuses for Apple: i tried <insert hack> and havent experienced any flicker since!!! Could this be a real fix??!!
Also, when I hear people with flickering problems say "fingers crossed", I just cringe. When you buy a 2000+ dollar computer, by no means should you ever have to even think "fingers crossed". That is just crazy.

Now the screen my BRAND-NEW 27", 2.8MHz, i7 iMac keeps turning off! It seems like it's going to sleep. The stupid thing won't stay on after I wake it up. After I restart it, then it'll stay on, but not after a sleep-wake-up. This aggravating to no end! A person can spend $3K on a computer and it won't work!!! My friends/family are laughing at me to scorn!

I already have an "appointment" with the local Apple Store-front for another problem (CPU fan spinning out of control), so they better fix this as well... along with the "caps lock" button light not working all the time. grrr

Well, I walked to a local AAR. They told me they sold the last Quad iMacs they had about 2 weeks ago, and that shipment of quads is delayed for sometime in January. I also asked one of the employees, if she knows about the screen problems, and she said that they are aware of. Also she said that's the reason why the shipments are delayed. So Apple surely is aware about the problem. It's about time to fix them. And they'll be getting the " problem free " ones in January. I'm gonna get one then.

Thanks for that info, Sumopro! I figured Apple had to be aware of this issue with this thread being as big as it is! I also figured that low-level personnel would be instructed to not acknowledge any rumors or problems in order to avoid a "run on Apple". I do agree with another writer on this thread that we should not have to go through this with a $2000+ computer, and that Apple should be more responsive about the issue by at least acknowledging that they are aware of the problem and are working on a solution. As noted above, I don't feel like lugging a 36 lb computer to the nearest Apple store (which, for me, is a 2 hr drive in traffic)to return it for another iMac that is very likely to have the same problem. I am assuming that since I have a 2-wk old machine and purchased the AppleCare plan, that whenever they do find a fix, I will be entitled to whatever the fix entails (either a replacement machine or replacement parts) at that time, and I can avoid the pain of returning multiple machines and setting up multiple machines. Am I wrong about this??

I 100% Agree. WE are entitled to a fully functioning machine. I am currently in the apple store, after lugging this 40lb machine with a truckie all the way through holiday traffic at the mall, waiting for them to call me to the genious counter. I don't even know what to expect, and its pretty ridiculous. I will let you all know how my experience is.
-Cliff

I have a brand new 27" iMac 3.33 Ghz that is doing exactly the same thing. I can work for several hours without a problem and have it start or it can start just a few minutes after I wake it from sleep mode. I have found a way of making it stop temporarily. Put the display to sleep and then wake it again in a moment or two. This action seems to bring it back to where it should be.
If any Mac engineers are watching.. it seems to happen more often if a pop-up window is open or there are multiple screens open.

Completely agree. After having gone through this issue with my MB Pro already I am not willing to do this again. Apple will get one chance this time after which I will switch after using Macs for 12 years now. As my iMac was delayed to January I hope that I will get a new revision though.

I read an article in a German Mac magazine (Mac UP) which talks about this forum post here but also states that with both 27 inch iMacs they could not see any problems...

SAD, my imac didnt flicker for the past two weeks. ... i was praying my batch had not been affected but the flickering started today.
doom

Well Cliff, I had an appointment today with a Genius Guy today also in a large Mall (South Center Tukwila, WA) on the busiest shopping day of the year. Traffic was miserable!

I had talked to a Tech (Tim) at Apple, Friday afternoon and he suggested I send the computer back to Apple, since I purchased it from there. I didn't want to do that since the chance of exchanging one problem for others as well as losing all my data, etc. didn't appeal to me.

So, he said that he could set-up a Genius Bar appointment and get the iMac i7 fixed there. I asked him if Apple had found out what was causing this problem and he said they had a hardware fix for it and could order the parts needed to fix it.

So, I was at the store for my appointment at 1:15 PM. Of course, the Genius guy didn't no anything about screen flickering problems nor was he aware of any hardware fix for this problem! So, he wrote it up and took my computer saying it would be in the shop 5 to 7 business days (During the Holidays.)

So, now I'm wondering if the technicians at this shop have the cure for this issue or have any knowledge of the supposed cure that Apple found for it!

I plan to see if I can get ahold of Tim at Apple Support and see if he will call the shop in question and make sure the technicians are aware of this fix he mentioned.

So, for now it's back to my 17" iMac G-4! Boy is it slow after working on that i7!