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 $15 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

2,046 Responses

  • Rob May 17, 20188:57 am

    Hello, I have a question. I have a motherboard (ASUS P5KPL-VM, which has G31/ICH7 chip), then … what would happen if I install the Xeon X5470 ?. The maximum of TDP. of this motherboard is 130W., I wonder if I install that processor on this board.

    Could it get to overheat ?

    Could the board die? or

    Would it need better refrigeration?

    I’ve also been seeing that it has 3 vrm phases without a heatsink, I do not know if that can cause something in the heating up.

    Or directly move from this board and upgrade to a more current system like the 8th Generation of Intel?
    Thank you.

  • vinod May 18, 20181:08 am

    I bought a asus p5g41t-mlx motherboard and I have done the bios update with the micro-codes, but after i power up the mobo with my xeon processor e5450 (which is modded), it stays a for about 20 secs and switch off automatically…. What should I do?, is there any changes to be done with the cmos ratio/ values? Please help
    My specs are – ASUS P5G41t-mlx
    Xeon e5450
    2GB DDR3
    palit 750 ti dual

    • kjafkjkaf May 20, 20182:45 am

      change the cpu fan it turns off cause of overheat

  • tom May 18, 20189:56 pm


    I have a Q9550 and I would like to make a mini-itx HTPC. The best mobo that I can find is the Intel DG45FC.

    Some reputable websites say this CPU and mobo are compatible, yet, others say they are not compatible.

    Please help!!! Will the Q9550 work with the DG45FC?


  • Kevin May 25, 201811:25 pm

    Hello i had some problem that my xeon is too damn slow the xeon even cant load windows in 4hours.

    But i do few tricks that i install windows on my pentium dual core and then i replaced to xeon procesor. ZThe boot works but take around 10minute to go to the desktop, and the cpu load is soo danm high, cursor stuter (even its fresh install) .if im going to reinstall windows with xeon processir it will freeze. ( in this trick if i go to safe mode, the xeon worked fine without any problem)

    Hope you can solve my problem

    I cant install windows 7 with xeon l5420, the installation takes forever so i do it with my dual core and swap the processor to xeon.

  • john789 June 1, 20189:53 pm

    I am very interested in doing this, as I didn’t even know that it was even possible, but I need some help.

    Here goes:

    My motherboard is a Gigabyte GA-P35-DS3L version 2.0 with 4 sticks of PC2-6400 2GB 2X1GB DDR2-800 for 4Gb of ram and a E2160 cpu overclock to 3.0 ghz. I checked the motherboard compatibility list and my mb is approved.

    I read the article here https://www.delidded.com/lga-771-to-775-adapter/

    But I still have a few questions, do I need to mod the bios to Update CPU Microcode in an Award BIOS? If so, I would like the keep the microcode for the E2160.

    I would like to get either the E5450 or the E5430.

    Also can you tell me what bios settings I need to make in the bios for this to work?

    Thank you.

  • Zach June 1, 201811:29 pm

    Confirmed this mod works on a Foxconn g41s-k motherboard with a L5420 Xeon. This Motherboard has a Max tdp rating of 65watts. Its not just plug and play though you will have to install a modded bios to bypass the CPU Max tdp warning screen. I was fortunate to have found one with the proper microcodes added as well.

    here is the link.

    This mod should also work on the g41s motherboard as well.

  • dev893 June 3, 201812:20 am

    So I have the CPU installed and first boot it works fine then if I reboot for any reason it freezes on the windows 10 boot screen, I’ve got the updated BIOS with microcodes, I modded the socket and added a sticker to the CPU I had to put the C2D e8400 back in, is it possible it’s a bad CPU?

  • Andrew June 6, 20186:58 pm


    I have P5B-MX mainboard which supports upto Q6600 Core 2 Quad CPU.

    I’ve got Xeon E5405 CPU (4 Cores 12MB cache, 2GHz, 1333 MHz FSB, 80W) for BIOS modification

    0. attached LGA 771 to LGA 775 adaptor to the CPU
    1. downloaded P5B-MX BIOS ROM file
    2. deleted support of Intel D and Intel 4 CPUs microcode
    3. injected suggested microcode for CPUIDs 1067a/10676/10677
    4. programmed P5B-MX mainboard with resulting BIOS
    5. attempted to boot the computer with Xeon E5405 and boot failed

    Did I make any mistake? Is there a reason why P5B-MX refuses to boot with Xenon E5405?
    NOTE: P5B-MX, FSB 533/800/1066(o.c)MHz, THD 130W

    I have put original E2200 CPU back in P5B-MX mainboard and the computer boots fine.

    Modified Xeon E5405 works fine in HP Vostro 220s computer without any issues (run Knoppix for a day).

    Thank you,

  • Sushil June 20, 20185:44 am

    I have ASUS P5G41C-M LX motherboard which booted perfectly fine with Xeon x5450 with the help of this mod.Before adding the cpuid patches, i was able to boot up the system with windows 7 but the system didn’t boot with Windows 10 x64 bit. After using the modded bios the system is working perfectly fine so far.I have also added Dell Slic 2.1 for Windows 7,so i just hope it would be useful for someone else.

    ASUS P5G41C-M LX Modded Bios:https://drive.google.com/file/d/1pX41QZvNR7ITQzIudbzmf8QgOdi7AKue/view?usp=sharing

  • sprit June 21, 201812:55 pm

    i have a asrock g41c-gs r2.0 will a x5460 work on my motherboard if i already have a q9400


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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.