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No Bootup with T9500 CPU

Hi

Hoping to upgrade my mid-2007 24” iMac to a ‘Penryn’ CPU, I very carefully read/absorbed lots of detail descriptions/accounts of how/why/what not to do, followed them meticulously and fitted a (allegedly) new T9500 CPU.

All back together, I plugged in and tried the start button.

Nothing - apart from the usual two quick buzzes from the optical drive. Took the ‘glass’ and the alloy frame back off, tried again and the same result plus noted very small flick of the CPU fan. Numbers 1, 2 and 3 of the LEDs to the right of the memory slots come on but nothing else happens, no chimes, no screen illumination, nada! - and I waited 15 minutes in hope.

Put the old CPU back in and away it goes, as reliable as ever.

Fearing I’d missed something I’ve done the same exercise three times now, all with the exact same result. I now KNOW I’ve not messed up because as soon as I put the old CPU back in, Bingo! away it goes, perfect boot, everything. I’m writing this on it.

There are lots of articles about how to do it, none mention any problems booting afterwards. There are only two posts that say the T9500/T9300 might be incompatible amongst the very many that say they are perfectly OK, other than speed reporting errors. The two I’ve found saying the CPUs are incompatible are effectively disputed in the following posts.

To be candid I really don’t care if the speeds are reporting incorrectly, all I need is SSE 4.2, which the T9500/9300 have and that will allow me to install Catalina with a patch.

Bottom line: Have I probably got, as I suspect, a faulty CPU, or is there somewhere some definitive information that says the T9500/T9300 are NOT compatible - and that incompatibility something is more than just the misreporting of speeds.

Will

Update (06/18/2020)

OK, I understand the concept of the EFI not being able to use the T9500/T9300. That said, I have never (happily) had to dig into my iMac’s bowels to see if the conflict might be there.

At the moment I’m on the latest (last ever?) update of El Capitan and I’d understood that any EFI upgrades came embedded within the OS updates as they were incorporated - or is that a misunderstanding as well?

A couple of examples of what spurred me to try and give my iMac a new lease of life can be found in the following links:

https://www.youtube.com/watch?v=JmLkRk3Z...

(even if his technique is a bit off)

and a whole series of articles like this from a well respected blogger, with very specific details regarding what will and what will not work:

https://lowendmac.com/2018/penryn-t9300-...

I’m running a Mid 2007 24” iMac 7.1 that I’ve had from new - apart from the screen size, just like the example used in the youtube I referenced. Is it possible there is some subtle difference I don’t know of that is foiling my attempt and could you point me in the direction of finding it please. It does seem a little hard to take that all of the youtubers/bloggers are full of it and peddling the theory for some reason best know only to themselves - unless, perhaps, to capitalise on the disposal of an excess of unsaleable T9300/500 CPUs?

Will

Update (06/30/2020)

It’s fixed!

It was a dud T9500. The replacement worked and booted straight up as soon as fitted.

No one was ‘at it’, it’s not a myth, it works and was a bit of an undertaking but with care and attention, quite possible. The only thing not reported correctly is the CPU details and the FSB speed. Who cares? It is working and markedly quicker. Most importantly it allows upgrades to a later OS.

To upgrade to Catalina, Dosdude1’s tutorial is excellent and all his patches and updates work well. Just make sure you follow it to the letter. I would put an image of ‘About this Mac up but can’t see how.

A 13 year old iMac, running Catalina, for the outlay of £125 and a few hours of work and effort.

Will

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There is still a bit of difference between the 20" and 24" firmware which could be a factor as the 20" has a Radeon HD 2400 XT and the upper end 20" and 24" have a Radeon HD 2600 PRO GPU.

I attempted one and I failed too (an Extreme CPU)!

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Hi Dan

I'm on the same ATI Radeon HD2600 PRO, so is it that and the firmware to support it causing the collatteral damage and stopping the system recognising the CPU?

It would be nice to find out the real reason, then maybe see if there's a firmware patch that will solve the problem.

I hate throwing perfectly good stuff away (ask my wife :-() and this faithful old iMac has proved to be worth every (expensive) penny I spent 13 years ago - but shouldn't be junked just because it's old.

Will

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@willumn - Sorry guy I have no answer here ;-{

Did you try a second CPU? Could you have a bad one?

If you find one let us know!

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The seller has sent another one today - but it's from China. They are claimed to be 'New', or 'Opened, never used' and working. Always a lottery with something like that and I don't really know who to go to to test one - other than asking someone with a known functioning system on a T9500 to open it up and swap it to see. A !&&* of big ask.

I'll let you know how things go. A definitive answer on all aspects of this would be good to pin down, since there are so many Macs that could get a new lease of life from the upgrade.

Will

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Hi @willumn, good to hear you resolved the problem! I have a 2007 iMac 21". I also replaced the CPU with a T9500. The computer boots and works fine. I see two problems. I can no longer read the SMC and the CPU is being reported as a Core 2 Duo 700 MHz. And the fan spins at 100%, which is very annoying. I wonder if you experience any of these problems too.

Wim

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Hi Will and everyone else. I don't know if anyone cares to keep on having an old 2007 24" iMac up and running, I just hate to dispose things and contribute to e-waste. So as I write this on my 2007 iMac which I have successfully been able to upgrade to MacOS 15 Sequoia, yep MacOS the latest version as off 10/2024, I wonder if I joined the discussion way to late. Anyway, Im facing some issues as posted before, the replaced T9500 is being reported as a 700Mhz Core Duo but powermetrics command reports both CPUs running at 350% at 2.6Ghz (which is what it is supposed to work at) so I don't know if the firmware just reports it as 700MHz overclocked at 2.6Ghz. I replaced the T9500 as well as the HDD for an SDD from OWC and it wasn't until I disconnected the original thermal sensor and installed OWC's one (which is part of the disc SATA connector) that the iMac booted again, before I only got 1 led near to the memory bank lighted up. Now Im wondering if the original thermal sensor needs to be plugged in also, according to OWC documentation, their thermal sensor should make the fans work "at normal speed", which as also reported, are running as a leaf blower and btw the SMC can't be read. Overall Im happy with the iMac been able to run latest browsers and the MSOffice suite with decent response.

If any one is curious, I used the OpenCore Legacy Patcher to upgrade the OS. Not a straight forward process, had to install Monterey first and then upgrade through Apple's System upgrade process (system preferences) and run OCLP post installation root patching a couple of times.

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Today, I connected (actually my kid did it) the original thermal sensor (keeping the OWC drive thermal connected also) and the fans went back to normal. So that was it.

CPU clock speed still reported at 700Mhz but everything working at a very acceptable response rate, like browsing, watching YouTube and using MS OFFICE. Not thinking of doing any heavy photoshop type of stuff

Is it as responsive as 2024 machine? Certainly not but works as good as a 2017 one, there are some glitches on the screen as some time parts of it are not refreshed properly but it’s a non issue

I have the same question regarding memory but haven’t got my hands around 4Gb simms.

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Very well done and yes, I am curious. Good to see someone who's actually done that upgrade to Sequoia. The thermal sensor bit went over the top of my head (maybe a memory-fail from my time squeezing Catalina onto mine) but is it a function/result of the SSD you used?

This image is of my Mac's basic report regarding the clock speed and it too shows 700MHz

Block Image

... and although I've never tried to dig deeper it pretty obviously functions correctly. I suspect misreporting but took the stance: "Does it matter?" Answered myself with a "No, it's doing all I need regardless of what it's indicating." so I ignored it for the last four years.

The one bit that does intrigue me is the question of the ACTUAL max RAM that will work. I have 6Gb, a 4Gb in slot 1, a 2Gb in slot 2 - but has anyone tried to put more in?

I don't have any more 4Gb sticks, or I would try it and see.

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Its all about firmware! Intel CPU’s load some of their micro-code from the systems ROM (EFI in our case here).

Apple never offered the T9300 or T9500 CPU’s so the micro code within the EFI is just not there! Sadly there are a few people who assume something works without doing it or understanding the limitations Apple imposes. I would make sure you have the newest EFI this series used as maybe it snuck in! I haven’t done this upgrade so I just don’t know if the issue is just a versioning issue within the EFI.

The highest of the T series CPU’s Apple used was the T7700. Later on Apple did the X7900 as the Extreme and then jumped to the E series in the 24” models.

So you have proved anyone telling us this series can support the T9500 is full of it!

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@willumn - Will you are a champion ! Can you help me to understand if I can do the same ? I have a Mid 2007 7,1 24” and would like to go past ElCapitan. I love this iMac although I have a newer one and it would be nice to get some newer OS on it. I found the guides to upgrade the 20” but nothing about 24”. I bought a used T9500 which “should” be good, of course I have no mean to test it. I have 4Gb RAM, 500GB SD, the graphic card is the Radeon Pro HD2600. I have NO IDEA how to check EFI.

Can you confirm it is the same setup ? And which instructions did you use to take it apart ? I took once off the screen to change the HD, but that is about it…

Any other tips or advise ? (from anybody out there) Is there a way to check if e.g. the EFI is the same ? (assuming it plays a role of course)

anyhow well done ! and Happy new year !

Angelo

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Hi Angelo.

Happy New Year and I hope this helps:

It is now quite a while since I did mine, so the memory fades. I used ‘dosdude1’s tutorial and software. In terms of sorting everything out, including file formats, his info is absolutely spot on.

If you don’t already have one you’ll need a HD carrier and adapter to locate a new SSD where the old 5” HDD was located. It is worth every cent in terms of speed changing to a SSD.

A search of Youtube should give several options of how to pull it apart. Get your self a good selection of the right sized Torx bits, two good suction cups and be careful, steady and determined. Make sure you pull very evenly. I took a photo of the internals before I removed a single screw, printed it, taped it over an aluminium foil tray, poked tiny holes in the printout where each screw was located and popped the screws in the relevant holes as they were removed. Getting them back in the wrong place isn’t a good idea. Be very careful (lots of photos) to route the cables where they should run. It’s easy to get one wrong and trap it. I had a false start or two because my T9500 was faulty. It meant the holes in the printout got ragged, so I stuck adhesive tape over the screw locations as reinforcing and remade the holes. Might be worth doing from the start.

I managed to find a 4Gb RAM stick to add to a 2Gb stick and mine now has 6Gb total. Take note of the fact that the OS misreports the T9500 but take no notice. It works extremely well.

Good luck, be careful and precise and you’ll be like me and get to keep using your beloved iMac.

ps had a couple of instances where I had to reset the PRAM after an update but otherwise no problems.

All the best.

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Will thanks this is extremely useful. I used the OS patch on a mini so I know that part better. Your suggestions about how to document it properly are extremely useful. I think that most important I need a place where to play with it over a couple of days without losing bits so at home over dinner table is not an option but I have a ‘den’ where I can organize this after holidays.

ssd is already in. I am only curious about the ram i thought it supports only 4GB ? Or is it like other macs who support more ? I should have one or two 4GB modules to test..

thanks for helping and have a great new year !!!

If I manage to do it I can post the results..

regards

Angelo

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@angelo_m

Angelo. For a pedant with OCDs like me, the prep, layout and correct result is a matter of life and death!! :-) Yes, it's not a 10 minute job and you don't need distractions, pets, or children 'helping' unless you're the highly experienced Mac wizard that I am not.

Don't forget to remove all the old heat conductive paste and put high quality new on - but not too much.

As for the 6Gb RAM option, I can't remember where I got the information from but it does work and the system accepts and reports it correctly. Something in the back of my memory says it may only be the first slot that accepts it - but that might also be a misfiring memory cell.

Sorry I'm feeding you this in dribs and drabs but it's been a while and I'm not at home to reference anything.

Good luck and please tell us how you get on.

Regards

Will

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Thanks again Will !

I will google more about the ram. I thought the banks had to have the same sets .. mysteries of firmware ? and I am not a great fan of Catalina, I forced it onto an old mini and it is indeed struggling a bit… but that is another story. I will surely try and post

but for now, happy new year to everybody ! Enjoy and be safe at all time !

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Hello,

did anybody try a CPU upgrade to Intel Core 2 Extreme X9000 S-Spec SLAZ3 on a iMac Intel 24" (mid-2007) mounting CPU X7900 and running OS X El Captain?

Thanks,

Marco

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Will Noble will be eternally grateful.
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