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iMac 24 2008 Replacing 8800GS GPU with Alternative?

MacHamster68

MacHamster68

macrumors 68040
Sep 17, 2009
3,251
5
i guess you could be right there , ok no precise facts , only rests purely on circumstantial evidence , but it would explain why some cards last 2 years plus and others not even last a year like in so called gaming laptops in which this card is fitted too , so 8800 cards that are getting used regular for gaming or other really GPU intense tasks fail sooner ,while others who just get used for websurfing or office work and never really get even warm last longer

Gaming puts a lot of pressure on the GPU , but a healthy GPU should withstand even temps of around 200 F when gaming , GPU's are build to get really HOT
i mean cpu 's for example are designed to shut down at about 176F and that are normal Temps for a GPU while gaming and not to be considered to hot
but this underfill material seams to be a weak spot and does not even allow the GPU to even get near HOT and the result is the GPU just drops dead suddenly
 
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schouser

macrumors newbie
Feb 8, 2011
14
0
I finally came across something that might explain why replacing a faulty Nvidia card and/or logic board only works for a couple days before failing again.

The PSU (power supply unit) could be responsible for undervolting/overvolting the logic board & graphics card. Thus, replacing them only temporarily solves the problem until the PSU has time to destroy the new hardware. In all of the scenarios I read about that had repeated failures, Apple only replaced the graphics card and/or logic board; the PSU was never replaced.

I found a different scenario concerning the Nvidia 8800gs where Apple replaced the graphics card, logic board, AND PSU; for this customer the new hardware did not fail again immediately.

I'm not trying to assign fault or blame, just trying to figure out where it problem lies. So my new theory is that there may exist some glitch or bug in the combo of Apple's PSU, Nvidia, & OpenCL that causes the PSU to over/undervolt. Anecdotal, yes. Small sample size, yes. The fact that I have absolutely no knowledge about tech stuff, absolutely. But it's the best theory I have, atm.
 
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andydckent

macrumors member
Original poster
Jun 2, 2009
59
4
Edinburgh, Scotland
MacHamster68 said:
it was a optional GPU and i doubt very much that apple did make a different logicboard only to fit a optional GPU

but it would be really interesting to know if it could be reversed taking the optional out and put in the base GPU from ati , because if it works it could give some people who have a failing nvidia 8800 a trouble free iMac again.. not for all of them its a option buy a new iMac , because for a iMac with failed GPU (so not working) you dont get much if you sell it like that and
after all the ATI Radeon HD 2600 PRO was not a bad GPU in terms of performance
Click to expand...

I believe this has been done before and is known to work.

Thing is I don't really want a less powerfull GPU after paying extra for a more powerfull one. Especially now the computer is over 2 years old.
 
panzer06

panzer06

macrumors 68040
Sep 23, 2006
3,282
229
Kilrath
flipster said:
I would do that, but I don't want to put something newer into an older system, or just in general something that doesn't belong in there. It could work, but the 8800 gs is suppose to be in there. I'd rather just get peace of mind in a new computer
Click to expand...

I agree with you, I just want to see someone do it (replace the 8800GS with ATI4850). :)

Cheers,
 
MacHamster68

MacHamster68

macrumors 68040
Sep 17, 2009
3,251
5
andydckent said:
I believe this has been done before and is known to work.

Thing is I don't really want a less powerfull GPU after paying extra for a more powerfull one. Especially now the computer is over 2 years old.
Click to expand...

i understand that very well , but why get a GPU fitted that might fail sooner then expected again ..some did fail within hours after fitting again
ok everyone has his own opinion ,and some like to push their luck ,
but so far i dont know about any repair scheme from apple , so if you got apple care , fine get a new old stock 8800gs fitted , as we know the cause of the problem is indeed the underfill material , which doesn't improve if lying on a shelf for years ...which would explain why some second or third cards fail even sooner
so i would think really careful about that , because if the card fails again you might not have apple care any more and a useless iMac on the desk in a couple month if not sooner

and despite the nvidia is better when it comes to 3 d gaming , but for anything else the ATI Radeon HD 2600 PRO despite having half the vram beats it , so i would not bother as i rarely play games on my Mac's apart from OS9 games on my PPC Mac's

still confirmation required if the swap can be done without problem , as some might fancy a working iMac
 
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flipster

macrumors 6502a
Mar 14, 2010
591
3
Boston
If my graphics card fails, should i call applecare or just go straight to the genius bar? I would like to keep it all on record of what happened, but if im correct, either way itll be recorded that its failed. right now, mines doing fine, in fact awesome at gaming on the most intensive maps
 
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andydckent

macrumors member
Original poster
Jun 2, 2009
59
4
Edinburgh, Scotland
Just want to bump this up again!

Could really do with finding out if anyone has replaced the 8800 with an alternative successfully?

My mac is 2.5 years old and have tried multiple times reflowing the 8800 which has worked for a about a week each time before breaking again to 'black screen'.

I'd like to repair it but don't want to spend £200-300 on a new 8800 if its just going to break again.

I may almost be as well selling for parts by the time you pay for everything.

Cheers!

Andy
 
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Dave J

macrumors newbie
Aug 4, 2011
4
0
andydckent said:
Just to let you all know that I have successfully had the faulty 8800GS with the less powerful but more reliable ATI 2600 Pro.
Click to expand...

Do you know the Apple Part Number for the ATI 2600 if you replaced it yourself?

Mines just died after 3 years. Had the 8800Gs and dont use it for gaming, so im not to bothered about a lower model card as long as its more reliable.
 
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andydckent

macrumors member
Original poster
Jun 2, 2009
59
4
Edinburgh, Scotland
Dave J said:
Do you know the Apple Part Number for the ATI 2600 if you replaced it yourself?

Mines just died after 3 years. Had the 8800Gs and dont use it for gaming, so im not to bothered about a lower model card as long as its more reliable.
Click to expand...

I believe the part number was 661-4663

This is the one I bought http://www.ebay.co.uk/itm/24-iMac-E...280?pt=PCC_Video_TV_Cards&hash=item2565d09870

Still working well after 6 months. I had a local independant mac repair guy replace it, he did it for £70 as I recall.

Andy
 
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andydckent

macrumors member
Original poster
Jun 2, 2009
59
4
Edinburgh, Scotland
Dave J said:
Thanks for the quick reply. Not a bad price. Do you find that your imac runs any cooler with that card?
Click to expand...

No problem, was just a bit of luck that I was browsing this at the same time.

Can't really comment on the temps as I installed smc fan control and boosted the fans a little as soon as I fitted the new card just to be on the safe side.

Andy
 
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Dave J

macrumors newbie
Aug 4, 2011
4
0
andydckent said:
No problem, was just a bit of luck that I was browsing this at the same time.

Can't really comment on the temps as I installed smc fan control and boosted the fans a little as soon as I fitted the new card just to be on the safe side.

Andy
Click to expand...

Cheers. Is he anywhere near London the man who did your imac? Got mine at a service shop at the moment for diagnostics but dont know what price there gonna give me yet. Probably a lot more if they have to source the part themselves.
 
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andydckent

macrumors member
Original poster
Jun 2, 2009
59
4
Edinburgh, Scotland
Dave J said:
Cheers. Is he anywhere near London the man who did your imac? Got mine at a service shop at the moment for diagnostics but dont know what price there gonna give me yet. Probably a lot more if they have to source the part themselves.
Click to expand...

Unfortunately not, the guy is based near Edinburgh so might be a little out of your way. :(
 
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Dave J

macrumors newbie
Aug 4, 2011
4
0
now worries. last question, lol. Did you have to pay customs charge on that from Hong Kong?
 
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DTN107

macrumors newbie
Feb 12, 2012
1
0
andydckent said:
Just to let you all know that I have successfully had the faulty 8800GS with the less powerful but more reliable ATI 2600 Pro.
Click to expand...

Was the heatsink setup from the 8800GS compatible for the ATI 2600 Pro?

Sorry to bump a thread from the past but my 24" iMac with 8800GS died out and as a student I don't have much funds to go to Apple to have them repair it.
 
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andydckent

macrumors member
Original poster
Jun 2, 2009
59
4
Edinburgh, Scotland
DTN107 said:
Was the heatsink setup from the 8800GS compatible for the ATI 2600 Pro?

Sorry to bump a thread from the past but my 24" iMac with 8800GS died out and as a student I don't have much funds to go to Apple to have them repair it.
Click to expand...

Hi

It was a while ago now but from my understanding it was a pretty straighforward swap, heatsink and all.

Hope this helps!

Andy
 
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applejack1923

macrumors newbie
Mar 20, 2012
4
0
Which speed iMac

Hi What speed is your 24" iMac as I am having same issue with a 3.06GHz early 2008 with a 8800GS and wondering whether I can use the Radeon 2600

Thanks in advance.
 
Y

yurarse

macrumors newbie
Apr 5, 2006
14
0
Brooklyn NY
I dont think there is alternative video card
I had my brother 8800 fixed; had a friend who has a machine that fixes logicboards.
he removed all old soldered from the chips and replaced with new ones.
Works like a charm

If there anyone in NYC want to get rid of their machine
let me know:D
 
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andydckent

macrumors member
Original poster
Jun 2, 2009
59
4
Edinburgh, Scotland
yurarse said:
I dont think there is alternative video card
I had my brother 8800 fixed; had a friend who has a machine that fixes logicboards.
he removed all old soldered from the chips and replaced with new ones.
Works like a charm

If there anyone in NYC want to get rid of their machine
let me know:D
Click to expand...

Yes there is ATI 2600 Pro. It's only 256MB thought not 512MB.

I had my 8800 reflowed (as they call it) twice before I replaced it but it broke again within a matter of weeks.

Andy
 
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PvdP

macrumors newbie
Mar 3, 2012
1
0
Same for Me!
-Reflowed my 8800 GS 4 times (worked for 3-4 weeks each time).
-Let it Reball (worked for 2,5 months).
-Reflowed it again 3 times (still works for 3-4 weeks each time)
-Finally Replaced the 8800 GS with the ATI HD 2600 Pro last week!

You can't use the heat-sink from the 8800 GS, it won't fit on the ATI Card.
When i ordered the HD 2600 Pro, it came without a heat-sink. Then i ordered a heat-sink on eBay. (heat-sinks from ATI HD 2400 HD 24-inch will also fit!).
Then it finally fit, without any modifications.
I only modified the Airwall (apple part 922-8588) by pasting a piece of foam to it, instead of paying $35 for a new Airwall (apple part 922-8589).

Works great for me, can't notice any difference for the 512MB to 256MB downgrade. Only if you want to use Final Cut Pro X: it will NOT support the ATI card.

I begin to like my Mac again....

PvdP
 
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kisteaz

macrumors newbie
Jun 10, 2012
1
0
Hi guys, just checking for the last time to be sure before I buy the ATI Radeon HD2600 to replace faulty nVidia GeForce 8800GS.

Will it really fit? I've heard some people saying the connector isnt the same. I found the card here:
http://www.thebookyard.com/product.php?cPath=34_164_175&products_id=7408.
Do I have to buy new heatsink with this card?

One more thing, it is really better to use the Radeon? I've people reporting OSX Lion become slow with this card.

Cheers
 
T

twistedbydesign

macrumors member
Oct 15, 2008
30
0
kisteaz said:
Hi guys, just checking for the last time to be sure before I buy the ATI Radeon HD2600 to replace faulty nVidia GeForce 8800GS.

Will it really fit? I've heard some people saying the connector isnt the same. I found the card here:
http://www.thebookyard.com/product.php?cPath=34_164_175&products_id=7408.
Do I have to buy new heatsink with this card?

One more thing, it is really better to use the Radeon? I've people reporting OSX Lion become slow with this card.

Cheers
Click to expand...

I dont know if you've solved you issues yet (I see your post is a few months old) but the ATI Radeon HD 2600 is a drop in replacement for the nvidia Gforce 8800 GS. I have done this and I recently posted a guide for swapping the cards. The card you posted the link to will indeed work. 661-4663 is the part number.
 
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