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

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2,204 Comments

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 $17 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

2,204 Responses

  • Plisken December 2, 20183:38 am

    Asus p5b-e + Xeon X5460?

    Reply
  • William Pete December 6, 201810:13 am

    I’m running an Optiplex 380 with a Xeon X5470 120W CPU
    You list the Opti 380 as having a 95W CPU limit which is not true.
    https://www.userbenchmark.com/System/Dell-OptiPlex-380/1942
    The correct limit is 120W. The QX9650 didn’t run for me probaly due to it’s 130W TDP.
    I’ve also run the Q9505S so R0 steppings are OK also.

    Reply
    • bm December 7, 20189:44 pm

      Hi William pete,

      I have OptiPlex 380. I have been thinking putting an xeon E5450 but I read that I will need to cut off the two tabs from the socket 775 OR cut grooves on the xeon cpu to fit in the 775 also a mod has to be put on the cpu.

      How did you do it please advise. b.miah@virginmedia.com

      Reply
      • William Pete January 7, 20199:38 pm

        If you don’t know how to do the mod after reading this website you can buy CPUs already modded. Then go to BIOS Mods.com and get a modded BIOS file.

        Reply
  • Joey G December 9, 20183:38 am

    Hello, I have an ABIT IN9 32X-MAX motherboard, what LGA 771 Xeon CPUs would be compatible with my motherboard? Thanks :)

    Reply
  • Jon December 12, 201810:11 am

    Hi all
    I have an Optiplex 755 Bios A22
    Have bought two X3363’s and the 771 to 775 sticker mod but neither have worked.
    The power light is solid orange and the fan goes on and off 4 or 5 times then nothing.
    Am i missing something ?
    Thanks
    J

    Reply
  • Soviet December 14, 20183:17 am

    Asus P5k Pro+ Xeon e5450 works fine

    Reply
  • Maxim December 15, 20182:03 pm

    lenovo l-ig41m3 v 1.1 + Xeon X5460 ?

    Reply
  • Sebastian December 16, 20188:25 am

    Medion MS-7366 (OEM version of MSI P6NGM-FD) + Xeon E5345 (B3 stepping/ SLAC5) works but crashes randomly, even after adding 771 microcode or disabling EIST.
    The BIOS doesn’t allow allow underclocking or undervolting but setting the maximum energy state in Windows to 86% (i.e. forcing multiplier to 6x with EIST) makes the system somewhat stable but still crashes after a long duration under load. The board worked fine with 775 CPUs (e.g. Q6600 G0 stepping) and Windows was freshly installed with the E5345.

    Reply
  • Cesar Cano December 17, 201810:59 am

    Probe INTEL XEON X5450 en una Intel DP35DP no soporta, probe en una Gigabyte GA-G41M-ES2L si funciona perfectamente.

    Reply
  • Evie December 19, 20183:59 pm

    I have a Dell XPS 720 that I installed a Xeon E5450 into and the BIOS recognizes it, but I cannot boot or install Windows, it either crashes silently and restarts or gives me a blue screen MEMORY MANAGEMENT error. I didn’t change my RAM configuration from the old CPU so I don’t understand this problem.

    Reply
  • Abcdef December 20, 201811:39 am

    Hello,
    i used socket 775 motherboard Gigabyte GA-EP45-UD3R rev. 1.1 which i seen should support my 771 socket CPU Xeon E5430 (stepping A) per its FSB and max. TDP details and i seen on that CPU was already a thing that seemed like a 771->775 reduction… so i just cut away two parts of the 775 socket to fit that 771 CPU and started computer after seating the heat sink and connecting FAN cable, all seems to work. Can you please add this CPU next to the motherboard to show other people it is supported?

    Issue is the CPU temperature is higher (probably because i was unable to click one of the FAN PINs to the mothrboard and i left old thermal paste as it seems liquid and i do not have new paste. The temperature is like 60C when relatively idle, but like 85-90C under heavier load. I see on ark.intel.com that maximum temp. is 67C – “Case Temperature is the maximum temperature allowed at the processor Integrated Heat Spreader (IHS).”
    Is it too risky to use the computer until my thermal paste arrive in like one week?

    Reply

Leave a Comment

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.