CPU Microcode BIOS modding questions/problems

OK MonarchX, as you stated you are using CPU Micro-code Rev. 1B for Ivy Bridge and from my experience on different motherboards of different producers, the Rev. 19 is better because at the same level of OC with the same HW, cooling system and BIOS code it is needed less VCore to maintain stability achieved.
An example: One of my i7 3770K is stable @4,5Ghz on a Gigabyte Z77X-UP5 TH with 1,15V with F12J BIOS and CPU Micro-Code Rev. 19 but when i’ve modded the F12J with the Rev. 1B i lost stability and to regain it i’ve upped the VCore to 1,155V.
I’ve tested Gigabyte, ASUS, MSI and ASRock motherboards on Z77 chipset and all the tested MoBos, except ASRock, with BIOSes with Rev. 19 of CPU Micro-code performed better than the same BIOSes but with Rev. 1B of CPU micro-code.
ASRock is the only producer that with modded BIOSes with Rev. 1B of CPU micro-code worked better than Rev. 19…
The only way for your rig is to try the same BIOS version modded with Rev. 19 of CPU Micro-code and check the stability with less VCore e.g. 1,305V.
The little difference of 0.005V may not seems a big vantage but when you’re @ the limit of the OC by the temperature or VCore that you feel safe for you system, every little drop (temperature or voltage) may help.

Try it and let us know if you’ll benefit or not.

Have a nice week-end!



Thanks for the explanation! I will definitely try and let you know. I shall de-lid my CPU and get Swiftech H240-X AIO WC (very low temps) soon to try to reach 5Ghz. This CPU Microcode may be the key!

I have an idea about this CPU Microcode and how it may possibly be good for overclockers, but I would need to use Multi-Meter to measure voltages and also know where to measure them. Sometimes voltage settings in BIOS are not real voltages. For example, every time I select 1.31v in BIOS, CPU-Z reports 1.32v. In reality, voltage can be as high as 1.33v. We don’t know unless we measure. Maybe with CPU Microcode 19 a Voltage offset of 1.31v in BIOS = 1.320v in CPU-Z and 1.330v in real life (multi-meter). With Microcode 1B a Voltage offset of 1.31v in BIOS = 1.320v in CPU-Z and 1.320v in real life (multi-meter). Is that a possibility? I know ASUS does this a lot, but you said that other brands also get the same effect from Microcode 19. Maybe Microcode 1B is just more accurate/precise and reports correct voltage, while Microcode 19 is less accurate and reports -0.01v than what actual voltage is. It just makes less sense for Intel to release CPU Microcode that performs worse UNLESS the one before was providing incorrect readings.

When you have tested Microcodes - have you used Multi-Meter to see if that voltage was truly the same? I am curious to know.

Yes, i have measured voltages with DMM on motherboards that offered point of measurement.

How do I inject a old Microcode in an GA-H97-D3H F4 Bios for my Xeon E3 1230 V3 CPU?
Thank you!

Link to the Bios:

Welcome at WinRAID Forum!

Why do you want to an old CPU Microcode for your CPU?


For Multicore Enhancement. So I can run all cores on 3,70 GHz. This function was deactivated by newer microcodes because of Intel. They didnt want you to do that. They want to sell their K-Cpus und Z-Boards.


Since I am not an expert regarding the CPU Microcode up- and "downgrade", I hope, that someone else will help you.


You can load BIOS image to MMTool.exe and replace all CPU MCUs with needed MCU.

Edit: On "Replace" tab select file with GUID "17088572-377F-44EF-8F4E-B09FFF46A070" then load module with needed CPU microcode to "Module file" field and press "Replace" button. Then go to "CPU Patch" tab and check version of microcode.

Edit2: Or you can place module file with needed microcode to the "Modules\CPUI" subfolder of UBU tool with the name of one of its original module files - "LGA1150.ffs", "LGA1155.ffs" - to replace it with your one (choose correct one with appropriate socket and family). And then use UBU tool to do the job.

ASRock just updated the BIOS for my Z97E-ITX/ac and I noticed that they inserted a new CPU Microcode but I have no idea what platform it’s for.

This is what MMTool shows:

The other three are for Haswell desktop retail and ES SKUs but the first one has a totally different platform type and CPU ID.

For some reason MMTool crashes when I try to open the Microcodes tab with that BIOS.

CPU Microcode 040671 BDW - 0B

@ jetflow:

Since the thread, where you had posted this info, has been designed just for the UBU Tool Guide and the News written by SoniX, I have moved it into this already existing thread about the CPU Microcodes.

@ Sonix:

Thanks for your info and advice. I haven’t realized, that jetflow’s post had nothing to do with the VBIOS modules.

hello, i have an issue adding a microcode to P7P55D-EVO bios. i extracted the latest microcode of the i7 860 (cpuid 106E5) from the latest microcode.dat and verified the file with the intelmicrocodelist.exe file (output: CPUID=106E5 Rev=07 2013/08/20 CRC=C6783666 Off=0 Size=1C00 Plat=0,1,4) then i tried to replace the old microcode with mmtool 3.26 but it says the microcode file is invalid. then i exctracted the current microcode and run a verification on it (CPUID=106E5 Rev=04 2010/04/05 CRC=F7762473 Off=0 Size=1800 Plat=0,1,4) then i found out that the sizes differ.

the most recent microcode looks okay to me since i can add it with the uefi mmtool to an uefi bios.

any suggestions?

i included the exctracted / the recent and the bios file.

Bios.zip (1.1 MB)

I wanted to revert back to Ivy Bridge microcode 19 on my Gigabyte z77x-up7 (3770K) from 1B. The bios says it is back at 19 but HWiNFO64 and AIDA64 say its still on 1B.

Are the programs showing the wrong value? I reverted the microcode using UBUv1.18.

@ johns36j
Look CPU microcode version in the BIOS settings. If there is value 19, then the version 1B puts the OS Windows.

@ SoniX
How do i make Windows 8.1 be the same as the BIOS?

Hmm. Do not tell me. I hope that someone from the of Forum Members will answer you.

The CPU Microcode is layed down within the BIOS and has nothing to do with the in-use Operating Systems.