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.

194 Responses

  • dale vasile November 15, 20148:06 am

    Intel DG31PR is in the list of the motherboard that support xeon cpus.(tested&worked e5450)
    you also say “We don’t currently know of any microcode updating guides for Intel BIOSes”
    that’s means dg31pr support xeons without modding the original bios.
    my problem is that my dg31pr don’t start with xeon 5120 or e5345.what I must to do to work?

    • syn November 15, 20142:04 pm

      Hi, please try all of the things mentioned in the troubleshooting section of this guide.

    • favi July 15, 20152:53 am

      Did you manage to update the microcodes for your BIOS?

      • dale vasile July 19, 20153:57 pm

        I couldn’t update the microcodes but i found a compatible cpu which worked with original bios.The cpu is E5440 SLBBJ.

  • narith March 18, 20154:18 pm

    does any know how to a microcodes to dell A15 bios?

  • Ronny May 25, 20157:59 am

    It doesnt go. e5450 ID 1067a how here written, bios 501.rom Asus p5kpl-am EPU and if i flash it with the new micros then he only run ten minutes and then out.

  • Ben June 3, 201510:45 pm

    A big thanks to this poster on Bios-mods for;

    “OptiPlex Bios Mods to Support Xeon Processors”


    I can confirm it works for Optiplex 760 , no more noisy fan!

    • Narith June 3, 201511:38 pm

      @Ben thanks for the post now i dont have to press f1 everytime it boots, and do you if this will make it so i can run windows 8 on?

    • dcp276 November 20, 20154:43 pm

      Any one perform this update on HP 6000PRO & dc7900 bios to post for download. Unable to perform on 6000Pro keeps failing with not enough space as mentioned above.

  • Li June 20, 20152:08 pm


    Mire yo tengo un Xenon E5450 metido en una placa base Asrock g41-gs. El caso es que me funciona bien pero quiero saber si el poner estos microcodes mejorarían algo y como podría ponerlos

    gracias un saludo

  • Li June 21, 20155:04 am


    Look I have a Xenon E5450 gotten into a motherboard Asrock g41-gs. The fact is that it works well but I want to know if putting these microcodes improve something and as could put

    thanks greetings

  • CuTMyHand's July 27, 20151:04 am

    Hi, I g41m-vs3 motherboard, help to find or make a microcode for xeon l5420 series, I found only g41m-vs3 re2 but that’s not good, because there are different configuration .

  • box August 10, 20157:34 pm

    whta l should do for x5460

  • Thomas Hoberg August 18, 20156:21 pm

    First of all: Thanks for this excellent site and all the documentation and hints!

    I’ve upgraded an Asus P5Q-E and an Asus P5Q3 with Xeon X5492 that I got cheaply with very few problems, I could all manage thanks to you!

    I failed with an P5Q-EM-DO (Q45), evidently because that one can’t handle a 1600FSB.

    I was initially a little scared about the 150Watts TDP figure quoted for the X5492 and then quite surprised, when HWinfo, HWMonitor and all these other tools which read on-board SMI sensors reported far, far lower figures: Actually no matter what I throw at these CPUs (like hours of Prime95-64), it’s very hard to push them beyond 50Watts!

    And it’s obviously not just erroneous readings from the sensors, because even with my old Noctua NH-U9B coolers running at ordinary 1600rpms, they simply don’t get hotter than 60°C after hours of stress testing.

    My only conclusion is that the 150W TDP figure on all three X5492 I purchased must be complete bogus!

    The way I understand the binning process to work (greatly simplified, of course), the chips are going through cycles of functional testing and cranking up the speed. If they plain fail at higher speeds, they stay in a lower bin.

    There is also another, inner loop in that testing, which cranks up voltages, to see if a functional failure at a lower voltages gets fixed using a higher one. If I understand correctly, this is quite normal if chip layers don’t align perfectly creating resistance, you can compensate that resistance to a degree using voltage, which creates heat (and hot spots).

    The voltage required for proper functioning and the best speed bin obtained eventually gets burned into the chip.

    Some chips may actually get downgraded beyond their physical capabilities, just because customer demand for top bins is also “binned” via Intel’s pricing: That’s the golden nuggets overclockers trade, I guess. But if a chip qualifies for the highest bin, it at least guarantees functionality at that speed level, even if it might require a bit of voltage to get there.

    Those parts, which just need voltage go function at the highst speeds have a good chance of winding up in the “black edition” bin.

    That’s the theory.

    In practice I believe *server* manufacturers don’t actually like having to qualify their designs from anywhere between 30 and 150 Watts, just because Intel says that’s what it might take to make a 45nm Harpertown run at 3.4GHz.

    And since there isn’t a sufficiently high demand for $1500 X5492 chips to justify pushing marginally qualifying chips to the kind of voltages to make them pass 3.4 GHz, they simply didn’t: Instead they picked the ones which would run 3.4 GHz at rather low voltages to stay well within the “comfort zone” of server cooling solutions.

    Another motive would be the fact that hotter operation will actually accelerate “wear” around these hot-spots and eventually increase the risk of malfunction and failure. Chip failure on servers has huge secondary costs for all parties involved, so everybody avoids those risks like crazy: It’s one of the reasons these X5492 actually are so expensive: They are the most trouble free CPUs Intel has been able to manufacture and validate as such.

    And brings me to my concluding remark and recommendation: The 1600FSB of the X5492 limits the chipsets it will run on (it won’t even start with a lower FSB) and it also limits further overclocking beyond 3.4GHz.

    But in turn these are the créme de la créme of all 45nm Penryn/Harpertown CPUs Intel has been able to produce ever! The absolutely trouble and error free CPUs Intel trusts to last “forever” at low voltage/wattage and at top speeds and with years of 24×7 use.

    I believe the 8-60Watts (idle to maximum load) I have actually measured reflect the combination of lowest voltage and perfect quality and will be obtained with *all* X5492, not just my lucky three!

    Mine are used to replace Q6600’s and even Q9950’s which never ran quite as cool even on default clocks. And while the Q6600 overclocked pretty well (but throttled on continuous loads beyond 2.7GHz) and the Q9950 was never solid beyond stock clocks, these will now sustain 3.4 GHz forever. They will need to do so and stay ultra reliable, because the systems they occupy have been passed on to my boys who are among the most critical power users of all, running nothing but top-notch games on them for hours and hours.

    And there we found that upgrading to i7’s of any generation did far less than upgrading the GPU, which is why I still consider an X5492 even running on 8GB of DDR2-800 quite a valid companion to an AMD R9 or Nvidia GTX 980.

    And they are rock solid stable and even relatively cool. Idle power is no issue either, because when they are idle they are off.

  • Dominic Buchina October 4, 20154:39 am

    What is the name of “your_BIOS.BIN” i cannot find it anywhere. it is for the GIGABYTE GA-EG45M-UD2H motherboard. do i just use EG45MUD2.F4 and replace it with ncpucode? i do not know the name of the .BIN microcode file for my motherboard.


Leave a Comment