LGA 771 to 775 Adapter (MOD) – Run faster Xeon CPUs in a Core 2 Quad motherboard



If you're looking to extend the life of your LGA 775 system, there's an adapter available now that will let you install faster (and usually cheaper) Intel Xeon processors (LGA 771) into a Core 2 Quad motherboard (LGA 775). These Xeons cost a lot less and are basically identical internally to the high-end Core 2 Quad CPUs.

List of LGA 771 & 775 CPUs + Current Prices

The pages shown below should help with comparing Xeon prices and specifications. The first link has all the LGA 771 and LGA 775 CPUs combined into 1 table (sorted by price), and the others are the original uncombined pages.

Where can I get an adapter?

Here's a current list of eBay sellers (sorted by price). The sellers are located all over the world, so you should be able to find one that's close to you, and most of them will also ship worldwide.

Why would you want to do this?

Xeons are usually MUCH cheaper

For example, the Xeon E5450 is equivalent to a 3.0 GHz Core 2 Quad Q9650, and it currently costs about $6 on eBay (usually much less than the Q9650).

Other good deals on LGA 771 Xeons include:

For detailed specs on all of the Xeons and a full list of current prices, take a look at this page.

Xeons also typically overclock better

Additionally, if you’re interested in overclocking (making the cpu go faster than its default speed), Xeon processors are usually made from the best silicon, so you can typically achieve higher overclocks with them.

Someone that recently did this mod successfully overclocked a Xeon X5470 from 3.33 GHz to 4.5 GHz on an ASUS P5Q PRO motherboard, so you can achieve really good results with these Xeons.

How does the adapter work?

The adapter is basically an electronic circuit on a sticker, and you place it on the Xeon processor (as shown in the picture below). This switches two of the pads on the bottom of the Xeon to make it compatible with a Core 2 Quad motherboard.

Xeons that are compatible with this adapter

This adapter is only compatible with LGA 771 Xeon processors. If you're unsure what LGA 771 means, it's the name of the CPU socket used in some Xeon motherboards. And in comparison, LGA 775 is the name of the socket used in Core 2 Duo/Quad motherboards.

LGA 771 to 775 Adapter

Minor modification to the LGA 775 socket is also required

If you look at the LGA 775 socket in the picture below, you'll notice two tabs are circled in red. These tabs are there to stop you from installing a non-LGA 775 processor, and they'll need to be fully removed before you can install an LGA 771 cpu.

The tabs are pretty easy to remove if you have a sharp utility knife or box cutter (just be careful not to damage or bend any of the socket pins near the tabs).

Important: Make sure that you fully cut off each of these tabs. If they're not fully cut off, the processor may not align or seat correctly in the socket, which will stop it from making contact with all of the pins. If this happens, your system will likely fail to boot.

Once the tabs are cut off, you can use tweezers to safely remove the pieces from the socket.

The socket will then support LGA 771 or 775 processors (you can still reinstall your old processor if you ever need to).

Tabs to removed from the LGA 775 socket

2,475 Responses

  • Abhi August 23, 20201:45 pm

    I am new to modding…….. My old Lga 775 machine has core 2 duo e8500 with 3gb ddr2 ram with Mercury g31 motherboard. I am looking for a new motherboard which cn support Xeon x5450 processor but here Zebronics G41-D3 (https://zebronics.com/products/zeb-g41-d3-lga-775-socket) is only available which is not listed in compatible motherboard list. Will it support Xeon x5450 processor after modding? Will this motherboard support 120w processor?
    Someone please guide me……. I really want to build this computer with xeon x5450 processor…….

  • Abhi August 23, 20208:01 pm

    I am new to modding…….. My old Lga 775 machine has core 2 duo e8500 with 3gb ddr2 ram with Mercury g31 motherboard. I am looking for a new motherboard which cn support Xeon E5450 processor but here Zebronics G41-D3 (https://zebronics.com/products/zeb-g41-d3-lga-775-socket) is only available which is not listed in compatible motherboard list. Will it support Xeon e5450 processor after modding? Will this motherboard support 80w processor?Do i need to update the BIOS?
    Someone please guide me……. I really want to build this computer with xeon E5450 processor…….

  • cicakbengong August 27, 20203:14 am

    i’m using asus P5B + xeon e5405 processor (2GHZ/12MB) with last bios update version (2104).
    After power on looks like normally. But there’s error information if Bios detecting unknown processor type. Then to continuing i press F1 keyboard button. After that can’t start boot up form hard drive or cdrom or flashdrive.
    Any solution for my problems until i can pass boot up drive process ?

  • Geralt September 14, 20205:55 am

    Hi. I completed this mod with GA-EP45-Extreme (DDR2) with Xeon X5460, if this anybody help :)

  • lwizbicii-==' September 19, 20207:24 am

    76y l t know wha I owe yu uys

  • orth September 24, 20205:37 am

    Works with Gigabyte GA-G41M-Combo and X5450 – didn’t notice any instability despite processor being 120W TDP whereas motherboard declares support only up to 95W TDP CPUs. Altough overclocking fails even at the slightest multiplier change (IDK whether it is a matter of crappy PSU or mobo’s VRM being stretched to its limit) – so bear in mind that your own results with such a config may vary (so consider buying E series Xeon for this motherboard).

  • beltrixx October 3, 202010:41 am

    Back in the day I followed the instructions here to use a Xeon L5420 (SLARP) with my Asus p5kpl/1600. I had to update BIOS microcode to accept it, though. It is running smoothly since then (three years ago).

    • HDW October 18, 202011:35 am

      Can you share with me microcode file that is needed for xeon L5420,my motherboard asus P5G41T-M LX3

      • beltrixx October 18, 202012:57 pm

        This thread includes the needed files : http://www.bios-mods.com/forum/Thread-p5k-se-Xeon-771-bios-mod-request :

        Extract the files inside “lga771_microcodes.zip” anywhere on your computer
        Extract MMTool_322_1B_21Fix.zip anywhere on your computer

        These were the instructions I followed three years ago to complete the process. I’m not an expert, just a hobbyist, so I will not take responsibility for any failure / issue / problem during this process.

        1) Open the ROM file with MMTOOL
        2) Choose the “CPU PATH” tab
        3) browse for the cpucode (*.bin) files (extracted from lga771_microcodes.zip) and insert it one by one. I just inserted
        the ones I wanted to be specifically supported so, in my case, I googled “cpu world xeon L5420” to know the exact CPUID’s
        for this particular processor, which were :
        10676 (SLARP)
        1067A (QFVZ, SLBBR)
        4) Once you have inserted the microcodes, save the modified BIOS image to C:\
        5) Reboot your PC and press Alt+F2 to access the Asus EZ Flash application (I read it wasn’t safe to use Asusupdate app for Windows).
        6) Select the modified BIOS file from C:\ and wait for the flashing process to end, reboot and load default settings.

  • Mario Avila October 9, 202010:30 pm

    Intel Xeon X5460 Funcionando bien en una Motherboard Biostar G41D3+. No dio problemas hasta el momento

  • HDW October 19, 20208:21 am

    Thank you for the share,very helpfull.

  • Wojtek November 19, 20201:03 pm

    I’m from Poland .I’m sorry but my English language is pure, but I have got Foxconn G31-MXP and my Xeon X5460 works good. First I have intalled “mod” P08 from unknown internet page. Windows colapsed. Then I back up my P08 bios. I don’t now what happened, but Xeon 5460 started live.And he works good now properly..I am amazed what happened, but I’m happy, that’s what it is.
    Best regards.


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Problem with this MOD? Please read the troubleshooting section before reporting a problem. If that doesn't help, please tell us all of the things you've already tried.

Unsure about compatibility? Please read the motherboard compatibility and tested motherboards sections of this guide.