A little backstory on this project : I ordered an iMac 9,1 2009 model off eBay. Came in, it was actually a 2007 model. Seller didn't want to pay for shipping back and have to try to relist it, so I got it for almost nothing. Did a little research, the only confirmed upgrades seemed to be the T9300 and T9500 if you want Mojave compatibility. Unfortunately those processors cost more than the entire unit, so I dug deeper and it appears there were several other options for compatible processors, namely the T6400 / T8100 / T8300. All 800FSB, Penryn, Socket P, 35W mobile processors. (Note there are other processors as well, find the full list here : https://en.wikipedia.org/wiki/List_of_Intel_Core_2_microprocessors#"Penryn",_"Penryn-3M"_(standard-voltage,_45_nm)
Unfortunately no one has listed any of these as having been tried on the 2007 iMac 7,1. The T6xxx series are VERY cheap, the T6400 can be had on eBay for under $3.50. The T8100 is about $7, while the T8300 is around $25. The 6xxx series is only a 2MB cache, so while it was tempting to get the cheapest, I went for the T8100, with 3MB cache, 2.1Ghz clock speed and around $7.
I spent about 40 minutes taking the iMac apart and changing out the processor. (I'm admittedly no pro at taking them apart. It would have been less than 30 minutes had I not misrouted the SATA cable and had to take it back apart again to fix that halfway through re-assembly.) While I was there I cleaned the fans and blew out the inside (11 years worth of dust it appeared).
After re-assembly, the processor shows as a 800Mhz Core 2 Duo but benchmarks correctly. As you can see if it pretty much identical speedwise to the T7300 that came out of it. The 800Mhz appears to be just a symptom of the fact Apple never put a T8100 in any machine from the factory. The T8300 WAS an Apple Processor, so it would likely show up correctly in About This Mac.
Before upgrading the processor, a working patched Mojave USB installer would not even begin to boot on this machine. It would show the Apple logo and nothing else, no bar, no progress, no nothing. After the CPU upgrade, it works fine. Boots normally and installs normally. After installation and running the patcher, everything works (except backlight control, see below) including Wifi, Bluetooth, Siri, iSight Camera, DVD Playback, Video Acceleration, etc.
Per this post, I replaced the single file, took ownership, and rebuilt the Kextcache and voila, native backlight control is working. https://forums.macrumors.com/thread...ed-macs-thread.2121473/page-679#post-27615822
This machine had 2GB and a small 64GB Vertex SSD. I did upgrade to 4GB ram and even tried 6GB ram, but the difference from 4-6 was not worth the cost in my opinion. A single 4GB DDR2 SoDimm is about $35 currently, while a 2x2GB kit is around $10. The system is VERY usable with 4GB and an SSD.
Finally I decided to try my luck and install Catalina as well. Downloaded and created a full USB installer, booted to the installer and manually updated Filesystem to APFS, then performed an in place upgrade. The patcher installed Catalina, all the patches, and the APFS booter all by itself and everything worked perfectly. Lost backlight control and didn't try to fix it, but everything else appeared to have worked flawlessly with Catalina, on a 2007 iMac! Pics attached below for posterity.
Unfortunately no one has listed any of these as having been tried on the 2007 iMac 7,1. The T6xxx series are VERY cheap, the T6400 can be had on eBay for under $3.50. The T8100 is about $7, while the T8300 is around $25. The 6xxx series is only a 2MB cache, so while it was tempting to get the cheapest, I went for the T8100, with 3MB cache, 2.1Ghz clock speed and around $7.
I spent about 40 minutes taking the iMac apart and changing out the processor. (I'm admittedly no pro at taking them apart. It would have been less than 30 minutes had I not misrouted the SATA cable and had to take it back apart again to fix that halfway through re-assembly.) While I was there I cleaned the fans and blew out the inside (11 years worth of dust it appeared).
After re-assembly, the processor shows as a 800Mhz Core 2 Duo but benchmarks correctly. As you can see if it pretty much identical speedwise to the T7300 that came out of it. The 800Mhz appears to be just a symptom of the fact Apple never put a T8100 in any machine from the factory. The T8300 WAS an Apple Processor, so it would likely show up correctly in About This Mac.
Before upgrading the processor, a working patched Mojave USB installer would not even begin to boot on this machine. It would show the Apple logo and nothing else, no bar, no progress, no nothing. After the CPU upgrade, it works fine. Boots normally and installs normally. After installation and running the patcher, everything works (except backlight control, see below) including Wifi, Bluetooth, Siri, iSight Camera, DVD Playback, Video Acceleration, etc.
Per this post, I replaced the single file, took ownership, and rebuilt the Kextcache and voila, native backlight control is working. https://forums.macrumors.com/thread...ed-macs-thread.2121473/page-679#post-27615822
This machine had 2GB and a small 64GB Vertex SSD. I did upgrade to 4GB ram and even tried 6GB ram, but the difference from 4-6 was not worth the cost in my opinion. A single 4GB DDR2 SoDimm is about $35 currently, while a 2x2GB kit is around $10. The system is VERY usable with 4GB and an SSD.
Finally I decided to try my luck and install Catalina as well. Downloaded and created a full USB installer, booted to the installer and manually updated Filesystem to APFS, then performed an in place upgrade. The patcher installed Catalina, all the patches, and the APFS booter all by itself and everything worked perfectly. Lost backlight control and didn't try to fix it, but everything else appeared to have worked flawlessly with Catalina, on a 2007 iMac! Pics attached below for posterity.
