LGA 771 Xeon Microcode – How to MOD Your BIOS



In this guide, we'll cover how to add the LGA 771 Xeon microcode to your BIOS. This is sometimes necessary for people doing the LGA 771 to 775 MOD.

Note: Microcodes are current as of 2018-12-02 (source). They were last updated by Intel on 2015-08-02.

How will updating the microcode help?

It can restore missing CPU instructions

If you did the LGA 771 to 775 MOD and notice missing CPU instructions (such as Speedstep, SSE 4.1, VT-x, or CompareExchange128) adding the Xeon microcode will usually restore that functionality.

It can also improve system stability

Microcode updates usually fix bugs or add new features, so by updating the microcode, you can sometimes make your system more stable.

LGA 771 Xeon microcode guides

Important: Make sure you do a FULL BIOS reset after updating your microcode.

If you have an Award, Phoenix, or AMI BIOS, the guides shown below should cover everything you need to know to add the LGA 771 Xeon microcode to your BIOS.

How can I tell what type of BIOS I have?

You may see the BIOS type when you turn on your computer or enter the BIOS. If you don't, you can use a program called CPU-Z to look this up (it should be listed as BIOS Brand in the Mainboard tab).

Note: AMI is short for American Megatrends Inc., so you may also see it listed the long way.

LGA 771 Xeon microcode files

Note: You don't need to download any of these files if you're using one of the guides shown above (they already have the correct microcode files).

  • Desktop LGA 771 and LGA 775 microcode
    • If you're trying to add LGA 771 Xeon support to an LGA 775 motherboard, this is the recommended file to download. It will allow you to not only add the LGA 771 Xeon microcode to your BIOS, but you can also update your processor's similar LGA 775 microcode (which is probably a good idea).
    • Contains microcode for all Core 2 Duo and later desktop processors (no Pentium 4 or mobile support).
    • Also contains the LGA 771 microcode shown below.
  • LGA 771 microcode

When you unzip one of these files, you'll see a bunch of individual microcode files that have filenames like this:


Here's what the different parts of the filename mean:

  • cpu0001067a - 1067A is the CPUID that is supported by this microcode
  • plat00000044 - plat is short for platform. This tells which sockets are supported by the microcode.
    • LGA 771 microcodes have a 4, 40, or 44 in this section
    • Desktop LGA 775 has a 1, 10, 11, B1, or 91
    • And for mobile LGA 775 it's a 20, 80, or A0
  • ver00000a0b - a0b is the version number
  • date20100928 - 2010-09-28 is the date the microcode was last updated

Which microcode files should I set aside?

You'll want to set aside all of the microcode files with your processor's CPUID (how to get the CPUID). There should be at least one of these for each platform, and you should go ahead and update the microcode for all of the platforms that you want your motherboard to support.

Note: If your CPUID ends in an "h" and you don't see microcode with an "h" on the end, just ignore the "h" because it isn't actually part part of the CPUID. That just means it's a hexadecimal number.


So for our E5450 (E0 stepping SLBBM) with a CPUID of 1067A, here are the LGA 775 and LGA 771 microcode files with a CPUID of 1067A:

  • cpu1067A_plat44_ver00000A0E_2015-07-29_PRD_A3107D75
  • cpu1067A_platB1_ver00000A0E_2015-07-29_PRD_59BF808E

If you have that processor and want to add the LGA 771 microcode and update LGA 775 microcode (which is recommended), you'd want to set aside both of these files.

What to do if you don't have an Award, AMI, or Phoenix BIOS

Insyde BIOSes

If you have an Insyde BIOS, there's a more advanced guide on manually hex editting a BIOS to add microcode. It is available here.

Intel BIOSes

We don't currently know of any microcode updating guides for Intel BIOSes. We've also heard that Intel may be using a secure checksum to prevent people from modifying them. If this is the case, it would prevent the manual hex editing method used for Insyde BIOSes.

Dell BIOSes

Dell often makes their BIOS updates available in an .EXE file that cannot be extracted by regular unzipping programs, so you'll need to use the trick shown below to extract it.

How to extract the BIOS ROM file from a Dell .EXE file

You can extract the actual BIOS from a Dell .EXE file with the following command:

DellBiosFilename.exe /writeromfile

This needs to be done from a DOS command prompt window.

Other BIOSes

If you have a different type of BIOS, you may be able to update the microcode by manually hex editing the BIOS. If you're interested in trying that, read the Insyde BIOS modding guide.

You may need to update the microcode in multiple places

If you're hex editing your BIOS to update the microcodes, we've noticed that some BIOSes have the same microcode in multiple places. If that's the case with your BIOS, make sure you update the microcode in all of the locations. Otherwise, it may not work.

Where to go for help

If you have questions about updating an Award, AMI, or Phoenix BIOS, leave a comment at one of the guides mentioned earlier.

If you need help with a different type of BIOS, we recommend asking for help at the following places: bios-mods.com, overclock.net, or forums.mydigitallife.info.

196 Responses

  • Vincent12 February 21, 20161:56 pm

    @Dominic Buchina

    Maybe a little late, but here’s no answer till now, so I hope this helps.

    Your Question:
    What is the name of “your_BIOS.BIN”? i cannot find it anywhere. it is for the GIGABYTE GA-EG45M-UD2H motherboard?

    “your_BIOS.BIN” is an example name: It describes to use your BIOS file you downloaded from gigabyte. You BIOS file of course is called “EG45MUD2.F4” , so please replace “your_BIOS.BIN” with “EG45MUD2.F4”!

    Your Question:
    do i just use EG45MUD2.F4 and replace it with ncpucode?

    No, please don’t replacen EG45MUD2.F4 with any file. “ncpucode.bin” is a separate file which you create with a command shell (temporarily). It is used to add further microcodes to your BIOS without to have to delete old LGA 775 microcodes from BIOS. This is necessary because cbrom195.exe can’t edit directly the microcodes in BIOS. CBROM195.exe just can move microcodes around.
    So there are few more steps necessary to keep the old LGA775 microcodes in BIOS, and to add further Xeon microcodes to it.

    =>How to update cpucodes in the Award BIOS: (Click to show)

    • Alexander January 3, 20172:56 am

      Здравствуйте! Нужна помощь! Системная плата Asus P5KPL-AM IN/ROEM/SI Процессор Xeon l 5408 Нашел прошивку под свою плату прошил биос больше не ругается НО компьютер стал дико тормозить в чем причина! Если я скачал не тот мод просьба скиньте ссылку на правильный! Спасибо.

      • Alexander January 3, 20172:58 am

        Системная плата Asus P5KPL-AM IN/ROEM/SI

        • Alexander January 3, 20172:59 am

          Системная плата Asus P5KPL-AM IN ROEM SI

      • Dnai October 1, 201811:31 pm

        Downaload and flash it for all 775 and Xeon 771 mods

  • CHOPPERGIRL March 15, 201612:30 pm

    I lost Speed Stepping when I did this mod (and so my fan is always spinning on high… annoying!), so I am trying to add the Xeon microcode into a Dell Inspirion 560 Bios running a Xeon E5450.

    When I try to extract the Dell bios rom from the Dell exe file as per instructions above, it says Command Line Parameter not correct…


    I560-A06.exe /writeromfile

    • CHOPPERGIRL March 15, 201612:54 pm

      Never mind, I found someone had already done all the hard work lifing for me, but googling “Dell Inspirion 560 Xeon 5450 Bios update”. I found this thread of someone posting who was in same situation I was in with same Mobo (Inpspirion 560) and processor (Xeon E5450):


      and then using the “Try my mod of bios” link: https://drive.google.com/file/d/0B5mWzL5dLEtnWGR3TlFpdGszejg

      Click the download files icon at the top, download the entire zip, and extract.
      Run the Windows Flashing Utility, chose Open, then Click “Show all Files” in drop down open dialog tab, then select the included “BIOS” file (which should of been named BIOS.rom instead), then flash, and reboot. Presto, fan quiets down, and I got speedstepping back… thank god.

      This post is to verify his bios mod worked.

      • Derek April 21, 201612:05 pm

        THANK YOU so much for posting this! And to the person who did the leg-work. I have been researching and trying to get this to work for soooo long. Fan is acting normal now, and I am hoping this also will allow me to load W10? Would appreciate knowing if anyone else had any issues with moding Xeon 5450 for Dell Inspiron 560s (uses G43T-DM1 vA00 mobo), and if moding the BIOS allowed W10 64 to be installed? Previously I was getting the “CompareExchange128” error. Going to try it now that I applied the modded BIOS, and will post my results.

        • Derek April 21, 201612:24 pm

          Install of W10 64 totally worked on modded Xeon 5450 for Dell Inspiron 560s (using G43T-DM1 vA00 mobo). Again, thanks for posting/reposting this modded BIOS. Super happy!
          Syn, I think this was not yet added to your compatibility list yet (?).

        • CHOPPERGIRL April 21, 20161:26 pm

          You’re welcome. I’ve been running Win 7 x64 on a Dell 560 myself with the Xeon 5450, after flashing the BIOS with the microcode, with no problems.

          However, for me, resume from suspend does not work properly. It will sleep, and resume, but after the second or third time, it will blue screen on resume… so be aware of that potential problem. Hibernate works fine for me. It may have nothing to do with the XEON, but instead be because my motherboard suffered some kind of physical damage at some point in its past, as several of my USB ports don’t work under any process.

          Let me know how Sleep/Resume for Suspend works out for you. Test it several times, because it works fine the first Resume, but its several resumes later that it will no longer wake, and you have to hard reset and reboot it.


          • DPatten June 5, 20169:06 pm

            Exactly what I needed for my Inspiron 560. $12 X5450 from eBay and an adapter for $3. Flashed the BIOS, modified the CPU carrier and installed the CPU. Booted right up, no issues with fans. I was a bit concerned with the difference in the TDP for the X5450, but I haven’t noticed the fans spooling up, except when Windows Experience Index was run. Which went from 3.6 to 7.3 BTW. Made an old PC one heck of a lot more useful! If I could have found an E5450 as cheaply I might have bought that just for the lower TDP.


          • Vincent12 July 28, 201611:14 am

            I’m not entirely sure but perhaps another BIOS setting for Suspend helps (if available)
            [Suspend Mode] =>”S1 POS only” instead of S3

            After going in S3 sleep mode my old P5Q3 motherboard no longer worked.
            Same with an AMD Athlon XP2400. After some time CPU got broken after S3 sleep.
            I don’t trust S3 setting anymore.

            Other option:
            Maybe there are jumpers on your motherboard.
            Asus e.g. has several jumpers. Each of it is concerned for different group of USB ports (eg. rear panel; internal USB 9 pin header)
            Example P5Q3 manual page 47

            4. USB device wake-up (3-pin USBPW1-4, PS2_USBPW56, USBPW7-10,

            explanation USB Jumper set +5VSB is to grant usb devices like USB-keyboard from waking up from S3 sleep mode.
            +5V is to make it possible for waking up from S1 sleep mode (S1 only).

            Perhaps you find something similar in you DELL manual and/or motherboard (if available)

      • Radil September 29, 201710:16 am

        The link is not working, file deleted probably. Do you still have it and would you please send it to me on cyberfan1978@gmail.com. Thanks!

    • choppergirl airwar July 18, 201911:09 pm

      For those still looking for this modded bios to have Intell SpeedStep functioning on a Dell Inspiron 560 using a Xeon Processor… and have the processor not run at a constant 100% and the fan run at a constant 100%…


      My instructions file:

      This modded BIOS will give your Dell Inspiron 560 mobo
      the ability with an E5450 and other processors to use Intel
      SpeedStep, which will throttle your processor, and also
      stop your processor fan from running on 100%

      Download / get Dell560_A06_771_1067x.zip from :

      or from the original location below, if above link on my webserver don’t work: https://drive.google.com/file/d/0B5mWzL5dLEtnRHpLTW5VMVNSZGc/view
      (note in above link, it will say “Retrying” but that’s only for a preview, go ahead and click Blue Download button when it appears and works…

      Extract Dell560_A06_771_1067x.zip to a folder

      Run AFUWIN.EXE
      Click OK to bypass welcome Dialog

      On next screen click Setup tab (second over)
      Click “OPEN” button at bottom left of dialog box
      Change File type displayed in the open dialog box from just .ROM files to All files “*.*”
      Select file “BIOS” (it has no extension I guess)

      Click “Flash” Button and wait til it programs with red blocks, then green verify
      When it’s done, exit it…

      Restart computer

      Processor will now throttle, and you should instantly hear fan spin down
      from full blast to normal signifying everything worked…

      Note that there are some save webpages (this one and two others in the “Info” folder. And if you can’t extract the files, there’s a folder there with all the files all extracted so you can download each one…

      Original thread Page 1 – Author can be found here

      Original thread Page 2 – Author can be found here

      • Shockin95 August 2, 20194:39 pm

        This will work with a E5440 and not just the E5450 right?

  • CHOPPERGIRL June 6, 20161:43 pm

    You’re welcome. Poor mans quad core, right? It’s about 4/5th the power of an I7-920 clocked at stock. Most of the time it will run at 2000mghz and stay cool… when it spools up to 3000mghz under a heavy load the fans will kick in and race and you’ll know it.

    Unrelated to the CPU, I found that my Nvidia Gefore 520 card isn’t very stable at supporting hardware video acceleration decoding. This is a problem probably with all Nvidia cards (maybe just under Win7 x64 with no service pack upgrades). If you should find your computer randomly crashing on a video playback, or just randomly crashing, turn off video acceration in Firefox, Chrome, and VideoLan/VLC if you use those apps. Stable as a rock now, but I really miss hardware video acceleration, it really makes the system fly. You could be playing two videos full screen at once and the CPU would be at damn near zero usage.

    I never resolved the Suspend/Sleep unreliability problem, and just use Hibernation. This may be a problem with the Inspirion motherboard itself, or Win7 x64, or the Xeon/mobo combo…

    I maxed my RAM out to 8gb, and turned off SuperFetch (which is garbage and will thrash your harddrive). Its worth spending the extra bucks to max it out to 8gb RAM. An SSD drive would really make it fly… I find my slow SATA physical harddrive is the last major bottleneck on this system.

  • Kodak June 23, 20166:27 am

    I got a problem with x5470 as it is not providing CompareExchange128 even with latest microcode (a0b); any hints?

    • Vincent12 July 28, 201610:49 am

      I guess you patched with the correct microcode?
      =>cpu0001067a_plat00000044_ver00000a0b_date20100928.bin ?

      Important: Is CPU-Z showing the VT-x flag?
      If so already, the proper microcode is present in BIOS and I personally would see no option to get CompareExchange128

      • Kodak July 28, 201611:28 am

        Yes, I have somehow got used to the idea of not having this instruction :(

  • daniele July 11, 201610:51 am

    i don’t have .rom file of the bios of asrock p5bde.. there is only .exe how to do?

    • Vincent12 July 28, 201610:42 am

      @ daniele:

      There are different flash methods available for Asrock Boards generally.
      You need to download the BIOS (Instant flash method).
      So don’t take the Windows file!
      Please choose the China download server, because Europe mirrors often made problems
      (often downloading too small file, not complete)

      Extract P5B-DE(1.30)ROM.zip to your desired location.
      Then Rename extracted BISO file: “P5BDE_1.30” to “P5BDE_1.30.ROM”

      Then the microcode tool “MMTOOL_3.22_1B_21Fix-BKMOD.EXE” can open it.
      Go to CPU patch tab and insert your needed microcodes.
      Perhaps there is not so much free space left in your BIOS. File size is 512 KiByte.
      The newer Asrock boards have 1024 KiByte ROM size.
      =>How to update cpucodes in the AMI BIOS: (Click to show)

      BIOS flashing with the modified works via the Instant Flash from BIOS setup.
      Go through BIOS menu you should find Instant flash in the help bar on the downside how to start Instantflash from BIOS.

      • daniele July 29, 20166:38 am

        i have now the q6600 and i want change it with xeon e5450.. in the step 6 there are instructions for delete old microcodes.. the cpuid of my q6600 is 06fb, xeon e5450 e0 slbbm is 067a.. in the program mmtool i open the bios 1.30.ROM but,my doubt is, i delete the string with 06fb or 067a and then insert the microcodes of xeon?

        • Vincent12 July 29, 20163:26 pm

          No better don’t delete the Q6600 microcode, becaus after flashing this with 06FB/06F7 removed, it won’t boot with your Q6600 anymore for flashing.
          If yon remove the Q6600 microcode (CPUIDs, 06FB and 06F7 depending on steppings), make sure to replace it with the new version of microcode available in the microcode file.

          No you probably won’t need to delete any of the existing microcodes.
          But there are often a newer versions of microcode for LGA771 and 775, even for Q6600 available, Xeon 5xxx socket 771 and many socket 775 Quads/ Duos 65nm, 45nm, too.

          Often the newest BIOS still contains an old version of microcode file.
          Although Intel released the new microcode version for same CPU/CPUs before last BIOS release of motherboard.

          I recommend make a copy of newest, not modified, original BIOS
          Rename the file copy to P5BDE_1.30_mod.ROM for example.
          Now first just test out how many microcodes would fit in into BIOS until message appears, like that:
          “Error !! ROM space isn’t enough .It exceeded 4D4h Bytes”

          So then you have an overview how many microcodes (also dependend on size per microcode) can go in, without that error message.
          MMtool recognizes it if no more space is available. This is to ensure that microcode is fully put in and not just a part of it, which would make problems.

          I delete the old version and replace it with the same microcode, but newer version (bug fixes),
          + adding Xeon microcodes (newest version from Intel micorocde file”

          Newest versions of microcodes:
          LGA775: E0 stepping: Core2 Quads/ Core2 Duo (Yorkfield/Wolfdale) 45nm:

          LGA771: Xeon X54xx E0 stepping Harpertown (45nm):
          LGA 775: C0-stepping: Core2 Quad/ Core2 Duo (45nm):

          LGA771 C0-stepping: Xeon X54xx C0 stepping (45nm):
          LGA 775: G0 stepping: Core2 Quad Q6600, (Kentsfield), etc (SLACR) 65nm

          LGA 771: G0 stepping: x53xx Clovertown (65nm)
          LGA 775: B3 stepping: Core2 Quad Q6600 (Kentsfield) (SL9UM) 65nm
          ????cpu000006f7_plat00000001_ver000000xx_xxx??? not in Intel microcode data file! If existing, perhaps only in an LGA 771 Xeon mainboard BIOS???

          LGA 771: B3 stepping: X53xx Clovertown (65nm)
          ????cpu000006f7_plat00000004_ver000000xx_xxx??? not in Intel microcode data file! If existing, perhaps only in an LGA 771 Xeon mainboard BIOS???

  • Paavo November 23, 20163:39 pm

    Thank you for all the information and the files! ! :) I installed intel xeon L5430 In to a Compaq Presario CQ5215SC. It has a H-I41-uATX Eton motherboard and there is no bios update available for this mobo.
    I managed to copy the original bios with bios backup toolkit 2.0 and i added and updated the microcode and everything runs fine :) I was having problems with the cpu fan that was running full speed. now it works as it should be :) Only thing that went a little bit differently was the command on dos. I tried to use this AFUDOS bios.rom /P /B /C /N B/ but i just put AFUDOS bios.rom and it did the job :)

  • Vili December 15, 20163:55 pm

    mm im using intel dg41rq but evry bios file is .exe or .bio how i can get the rom file pls help

  • citizen January 13, 20176:11 am

    Thank you very much for writing this guide. I installed a Xeon E5450 on an MSI P35 Neo-2 FR using the sticker mod and modifying the socket so the cpu would fit. However, Windows 10 would still show my old E8600 (with only two cores) in the device manager and after manually removing it freeze on start-up. So I went back to my old E8600, downloaded the latest BIOS (Ver. 1C from MSI website) and added the respective microcodes as instructed in your guide, then flashed the bios using a FreeDOS bootable USB-Stick, finally did a CMOS reset via battery cut and reconfigured bios on first boot …. and what can I say, it worked like a charm. After first Windows boot there was still my old E8600 showing up (with only two cores) in the device manager as before, so again I removed it manually, then rebooted… this time Windows recognized the Xeon correctly with all 4 cores (so does CPU-Z) and has been running stable since. Performance increased remarkebly (e.g. no more lagging in Witcher 3). Thank you very much!

  • Michal January 15, 20177:16 am

    it seems my xeon e5450 lost speed stepping as the fan is working around 2500 rpm constantly. My motherboard (Abit IP35-E) does not recognize temperature correctly, it shows 98 degrees but when I check the temperature in Aida 64 it shows around 35 degrees for each core. I wanted to update microcode but I’m not able to open BIOS from manufacturer website (the archive is corrupted). Any idea how to solve above issues without updating microcode?

    P.S I’ve already reset my BIOS.

    • Michal January 15, 201711:06 am

      Ok, I made backup of my bios by uGuru for Abit and edited it like in the guide (Method 1). Everything went fine, but now I’m unable to install the system (Win 7 professional). After the Win 7 installator loads system files, the system reboots and it crashes on win logo screen. There’s BSOD visible for a moment, but it vanishes too quickly, so I’m unable to see what is written there…

      Any idea guys?

      P.S Now bios sees my xeon e5450, and it’s showing a CPU temperature around 60 degrees so I guess the microcode has been installed correctly.

      • Vincent-Schulz February 3, 20175:44 pm

        It looks like a stability problem, either RAM (incompatibilty) or defective RAM or too low Vcore.
        If it’s the RAM, try with one module only.

        I have several Gigabyte Boards with a Xeon X5470.
        And on all four boards the BIOS Auto doesn’t select optimal CPU voltage.
        That’s true!!
        So it’s plausible that this could be happening here, too, isn’t it?

        Does your BIOS support manual Vcore (CPU voltage) setting?

        If so, please try raise it. a little bit step by step and see if it runs stable.
        And please report back if that is helps.

        It’s worth a try at least.

        • Michal February 4, 20172:03 am

          Hello Vincent,

          Thank you for all your advises, really appreciate that. I decided to install the old bios and it works well. The only disadvantage of old bios is max fan speed at system startup but I regulate it by speed fan.

          So my Xeon e5450 is fully workable now.

        • Michal February 4, 20172:54 am

          Hello Vincent,

          Thank you for all your advices, I really appreciate that. Ultimately, I decided to install the old BIOS, without xeon microcode and everything went back to normal. The only disadvantage is max fan speed at windows start up. But I solve it by adjusting fan with SpeedFan. The system is stable, everything works fine. :)

          • Vincent-Schulz February 4, 201710:11 pm

            wish you successful testing.
            I hope it really is stable, especially under full load, for example with Prime95 stress test.

            Important here to have good cooling.
            And that there won’t be problems installing Windows 8 or Windows 10 (perhaps some time in the future).
            For this you’d need Xeon microcode, but at least Win 7 has support for some more years.

  • zack February 8, 20172:38 am

    help wanna ask something…why after i update microcode into g41m combo bios…. when i open cpuz …i cant see tdp max ….it was replace with brand id n blank box…no information…please help…tq

    • zack February 8, 20172:41 am

      my proccessor is correct….everything else is corecct but Tdp max info is missing n replace with Brand Id with no information just blank box… my proc is Xeon x5460 …mobo g41m combo rev 1.3…tq for reply


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