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 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 $20 (about $70 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

1,424 Responses

  • modforMe September 13, 20169:51 pm

    I am new to this forum. I have done successfully the hardware mod (Xeon X5450 into Gigabyte mobo ga-g31m-es2l).
    However, I cannot use the mm-tool to update the microcode for modified BIOS. For a start, the BIOS I downloaded from Gigabyte is only have the size of a normal AMI-BIOS file, and it ends in .10f, rather than .ROM! Therefore mm-tool won’t accept it!!! (even after renaming it!)
    Is there a way around this ‘hurdle’?
    By the way, the Xeon X5450 works, even without telling me I should enable missing instructions.
    But I see no performance improvements compared to the previous Core2Duo (3GHz)… No wonder, if the microcode still needs updating!
    Why don’t I get a proper BIOS file from Gigabyte?
    Help would be very much appreciated…

  • Daniel October 23, 20166:29 am

    Hi, i succesfully tested Foxconn mainboard G31MXP with two similar Xeons E5420 and L5420.

    Here are screens from CPU-Z:

  • Tonydanza October 25, 20161:05 am

    Hey I’m doing this with a 630i board from q8200 to x5460 on the board with 4x 2gb ddr2 ram and rx 470 and newest BIOS 750watt power mostly ddr2 Dell stock. It lets me load in but I get strange issues like internet dropping, or closing programs, when overwatching I get sound like an explosion that happena and goes that sounds like death, and mostly I think the heat is wrong for CPU idk I put back in the q 8200 and it runs fine tho but should the microcode inputed to work to solve this. has anyone done this with the 630i board and has done the mircocode. I have to bent pins that I have fixed but I don’t know if that’s another issue too.

  • Jeff_HxC2001 October 26, 20165:44 pm

    Dell Optiplex 380 (Intel G41Express Northbridge)
    E5450 (C0)

  • Jeff_HxC2001 October 26, 20165:46 pm

    Dell Optiplex 360 (Intel G31Express Northbridge)
    E5450 (C0)

  • Jeff_HxC2001 October 26, 20165:50 pm

    Dell Optiplex 330 (Intel G31Express Northbridge)
    E5450 (C0)

  • Jeff_HxC2001 October 26, 20166:14 pm

    Dell Precision 390 (Intel 975x Northbridge)
    E5450 (C0)

    Worked after the following operations :

    – Update the BIOS with a patched version to support the new 45nm CPU id (1067X)
    (Ask me if you want my patched version).
    – Force/Strap the BSEL2 signal to GND to force the FSB at 1066/266Mhz. (The CPU will run at 2.4Ghz).

    It is maybe possible to make this board running at 1333fsb, but i need to find the Programmer’s Reference Manual of this chipŝet to play with the clocks and patch the BIOS correctly.


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.