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 $27 (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


Leave a reply
  1. Quade

    Sitting on a P5KR mobo here with the latest BIOS (P35, 45nm supported, 1600mhz FSB supported). Going to get an X5460. Has anyone tried to start it up on the same mobo or at least P5K which is basically identical (just updated SB)?

    • syn Moderator

      The X5460 should work fine. All of these CPUs are essentially the same internally, and they’re just running at different clock speeds usually.

    • syn Moderator

      And, yes, the regular P5K is in the list of tested motherboards, and it worked with an X5460.

  2. Alex

    asus p5k-se + e5450 = work fine

  3. zombi


    I mounted a x3323 on hp dc78oo and work but with problems.

    After reset the bios (hard not soft because the bios settings is not accessible) and starting the PC the bios detect changes. If press F1 to save system rebooted and stay locked. Reset the bios again and press F2 not F1 system boot from hdd and work very well on winxp.

    I extracted the microcode from bios of hp xw6600 (xeon system) and I compared with microcode from hp dc series for 10676 cpuid (x3323). Only 2 bytes is different (platform) : 10h and 18h locations. In original bios for 10676 cpuid I have 46h and 01h. I changed this with (43h,04h) or (07h,40h) . If try to flash with this modification the tool say “corrupted bios”.

    The hp supplied a tool to make update only the microcode without full bios. I made similar modification but without success.

    – The system boot only one time after hard bios reset.
    – The bios setting is not accessible.
    – The HP logo not show on startup (not a big problem).

    Any body have any idea to solve this problem? Thanks to all!

  4. joe grehe

    Thank you for this site. I wish I found this page before I upgraded my system to Xeon. The pictures made the parts look larger than they really are and I had to use magnifying glass while I chip away the plastic tabs.

    I confirm that the MOBO HP IPIBL-LB (Benicia) works with Xeon E5450 SLBBM (E0). The BIOS requires a microcode update. After that, Win 7 detected the change and works flawlessly.

    The only problem I have is that the temperature reading for the CPU is wrong. Adjusting the TjMax value to 85 corrected this problem. And the only program that would let me make this adjustment is Open Hardware Monitor. All other Apps have this value fixed to 100.

    I used the stock heat sink from my old CPU and the temp idles at 32C. On 100% load, temp is at 61C. Max temp for this CPU is at 67C. Though the fan is spinning like crazy, I ran the test for an hour with the temp fixed at 61C. Not too bad, just noisy.


    • syn Moderator

      Hi, check out the troubleshooting section in this guide. It covers how to solve the loud fan issue.

  5. Austin

    EVGA 790i Ultra SLI + X5460 (C0) = failed…. (MB LED show “A0″ and no display)

    But I saw it can work with x5470…..It is really sad.

    Is there anyone can work fine with the same CPU and mb?

    • syn Moderator

      Hi, if it works with an X5470, it should also work with an X5460 because they are the same internally. I recommend trying the stuff in the troubleshooting section.

  6. Michael

    X5470 can work with P5Q3?

    • syn Moderator

      Yes, it should work fine.

  7. Kimonas

    I used a GA EP41-UD3L and a Xeon E5450 but it failed to boot. I also updated my nobo to the latest BIOSes and updated the microcode but still no luck. Is there anything else I could possibly do?

    • syn Moderator

      The MOD should work fine with that motherboard, so there’s likely an installation problem. Try the stuff mentioned in the troubleshooting guide, and if you’re still having problems, let me know.

  8. d3teur

    Motherboard model number: Dell Optiplex 380 w/ AZ0422 (E93839(
    Xeon model number (and stepping if you know it) : E5450 SLANQ (C0)
    (Optional) chipset, max FSB, max TDP, and supported LGA 775 processors

    just plopped it in and it worked! Everything else on the Dell was stock.

  9. BobF

    I am writing this on my Asus P5K Premium, using an E5472 Rev C0 Xeon overclocked to 3.3GHz @1.18V, with 4GB 1.8V Samsung M3 78T5663EH3-CF7 DDR2-800 RAM, Stock Intel HSF, and a microcode update. No problems so far.

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