Good day dear community... Shoutout to @m0bil for his work which made me inspired and gave me a starting ground.
Link to his thread for Imac 2011 Firmware mods: https://forums.macrumors.com/threads/imac-2011-see-more-uefi-firmware-mod.2257435/
Today might be a great day in the spirit of these machines we still love to tinker with.
I might have solved the overclocking puzzle of Imac 11,1-3 aka 2010 imacs. Mainly for unlocked CPUs but locked ones will still enjoy +1x multi.
According to ChatGpt, I have found the location of where the firmware *probably* sets the CPU multiplier on boot time.
EDIT: It looks like it needs more work but its very close. I think this change just sets the upper limit of the multiplier at a given P-state. It might be enough to work but i will look more.
The code i found is in the Module PowerMgmtDxe. (GUID: F7731B4C-58A2-4DF4-8980-5645D39ECE58)
0x199 is IA32_PERF_CTL and handles multiplier. ChatGPT told me to change this to a constant value that will override the default value. This is probably very useful if you have a unlocked CPU like the i7-875K
Otherwise you will only achieve full turbo all the time which is only +1x multiplier from stock. Still better than nothing. Will try to look for base clock tuning but that is way more complicated to change, have it stable etc.
I have NOT TESTED this myself but maybe i will soon. I hate the process of soldering on and off the EEPROM to change stuff. (I might have disabled write protect so maybe i can change it with software, i remember reading about this somewhere... would make things so much easier for me.)
If someone can test this it would be awesome. I will also create another thread because this might end up hijacking this thread with kinda off-topic information.
Feel free to test and report back to me. If you need a easy cmd patch like those @m0bil makes then i can probably fix that.
The resulting code that will set multiplier to 36 is: (0x24 is Hex for 36 and can be replaced with any number. 0x28=40x 0x2A=42x etc)
Link to his thread for Imac 2011 Firmware mods: https://forums.macrumors.com/threads/imac-2011-see-more-uefi-firmware-mod.2257435/
Today might be a great day in the spirit of these machines we still love to tinker with.
I might have solved the overclocking puzzle of Imac 11,1-3 aka 2010 imacs. Mainly for unlocked CPUs but locked ones will still enjoy +1x multi.
According to ChatGpt, I have found the location of where the firmware *probably* sets the CPU multiplier on boot time.
EDIT: It looks like it needs more work but its very close. I think this change just sets the upper limit of the multiplier at a given P-state. It might be enough to work but i will look more.
The code i found is in the Module PowerMgmtDxe. (GUID: F7731B4C-58A2-4DF4-8980-5645D39ECE58)
0x199 is IA32_PERF_CTL and handles multiplier. ChatGPT told me to change this to a constant value that will override the default value. This is probably very useful if you have a unlocked CPU like the i7-875K
Otherwise you will only achieve full turbo all the time which is only +1x multiplier from stock. Still better than nothing. Will try to look for base clock tuning but that is way more complicated to change, have it stable etc.I have NOT TESTED this myself but maybe i will soon. I hate the process of soldering on and off the EEPROM to change stuff. (I might have disabled write protect so maybe i can change it with software, i remember reading about this somewhere... would make things so much easier for me.)
If someone can test this it would be awesome. I will also create another thread because this might end up hijacking this thread with kinda off-topic information.
Feel free to test and report back to me. If you need a easy cmd patch like those @m0bil makes then i can probably fix that.
The resulting code that will set multiplier to 36 is: (0x24 is Hex for 36 and can be replaced with any number. 0x28=40x 0x2A=42x etc)
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