$7 2007 iMac 7,1 Mojave Upgrade

jowaju

macrumors member
Mar 7, 2019
45
49
0
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/threads/macos-10-14-mojave-on-unsupported-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.


Photo Aug 11, 8 00 13 PM.jpg Photo Aug 15, 6 06 39 PM.jpg Photo Aug 15, 8 20 02 AM.jpg Photo Aug 15, 8 21 48 AM.jpg Photo Aug 15, 9 13 53 AM.jpg Photo Aug 16, 12 54 44 PM.jpg
 

jowaju

macrumors member
Mar 7, 2019
45
49
0
The following processors appear to be compatible with the 2007 iMac AND allow the use of Mojave / Catalina:

T6400 - C2D - 2.0 GHZ - 2MB L2 - 800FSB - 35W
T6500 - C2D - 2.1 GHZ - 2MB L2 - 800FSB - 35W
T6570 - C2D - 2.1 GHZ - 2MB L2 - 800FSB - 35W
T6600 - C2D - 2.2 GHZ - 2MB L2 - 800FSB - 35W
T6670 - C2D - 2.2 GHZ - 2MB L2 - 800FSB - 35W
T6900 - C2D - 2.5 GHZ - 2MB L2 - 800FSB - 35W
T6970 - C2D - 2.5 GHZ - 2MB L2 - 800FSB - 35W

T8100 - C2D - 2.1 GHZ - 3MB L2 - 800FSB - 35W
T8300 - C2D - 2.4 GHZ - 3MB L2 - 800FSB - 35W

T9300 - C2D - 2.5 GHZ - 6MB L2 - 800FSB - 35W
T9500 - C2D - 2.6 GHZ - 6MB L2 - 800FSB - 35W

X9000 - Core 2 Extreme - 2.8 GHZ - 6MB L2 - 800FSB - 44W
 

EmlynDewar

macrumors regular
Aug 17, 2011
112
53
0
Chengdu, China
Is the SATA speed limited to 1.5Gbps on these? It's the only sore point I have running my ancient 2008 MBP.
Cool that you're dragging it into the modern era. A 12 year old computer!

What do you use it for?
 

mikehalloran

macrumors 68000
Oct 14, 2018
1,600
387
0
The Sillie Con Valley
Is the SATA speed limited to 1.5Gbps on these? It's the only sore point ...

What do you use it for?
Why a sore point? It’s still faster than a SATA III SSD. You do have to be careful that any SSD is backwards compatible — some are; some aren’t.

To the OP, you did replace the NV RAM battery while you were in there, right?
 

EmlynDewar

macrumors regular
Aug 17, 2011
112
53
0
Chengdu, China
1.5Gbps SATA 1 speed, not 1.5GBps.
SSD is still way faster than mechanical on this port, but it's a needless restriction on a chipset that supports faster.
 

jowaju

macrumors member
Mar 7, 2019
45
49
0
Is the SATA speed limited to 1.5Gbps on these? It's the only sore point I have running my ancient 2008 MBP.
Cool that you're dragging it into the modern era. A 12 year old computer!

What do you use it for?
No, you can see in the 2nd picture top right the negotiated link speed is 3 GBPS. Here's another one from Catalina showing the Link Speed and throughput. Remember this is a crappy, old 64GB SSD!Photo Aug 20, 3 12 40 PM.jpg
[doublepost=1566332146][/doublepost]
Why a sore point? It’s still faster than a SATA III SSD. You do have to be careful that any SSD is backwards compatible — some are; some aren’t.

To the OP, you did replace the NV RAM battery while you were in there, right?
I did not replace anything while I was inside other than the processor. Should I have?
 

mikehalloran

macrumors 68000
Oct 14, 2018
1,600
387
0
The Sillie Con Valley
I did not replace anything while I was inside other than the processor. Should I have?
Yes. It's easy. Use a CR2032 battery from the drug store instead of the high-heat BR2032 that Apple uses.

Lift the bezel and you'll see it on the right. Do not pry up—poke a toothpick or such through the slot and it will pop up so you can put the new one in. If you accidentally crack the flange anyway (it happens), put a piece of tape over the top, then a small piece of foam rubber between the battery and bezel to secure it.

When the battery gets too low, it can cause a black screen or weird artifacts on boot up, settings won't be retained, other issues. All over a $3 battery.