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

MODs

1,718 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 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 (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

1,718 Responses

  • atechol June 17, 20174:02 am

    Hello everyone.
    I have been researching the 771 to 775 mod for awhile now and just wanted to say thanks for all the information you guys have put together here.

    Reply
    • Han Solo June 17, 20175:22 pm

      I have done this twice. And I have to say to me it is much easier to just take a small round file and file some notches into the XEON CPU using an old core2 as a template. It is very easy to mess up the pins on the socket trying to get the plastic tabs out of there and you can take your time with the file and do a pretty neat job with not much effort.

      Reply
  • atechol June 17, 20174:05 am

    Bbtw, I just successfully installed an x5450 in a HP Pro 3000 Microtower with the information found here. Thanks Again!!!!

    Reply
  • paul ferguson June 17, 20179:23 am

    Just finished the mod with a Asus P5K PL SE and a X5460 ,all running OK but like a few other posters have said in order for windows and various programs to identify the Xeon and not keep reporting my old Core duo 8500 i installed the new bios 3 times and did 3 resets and load defaults .

    Reply
  • Han Solo June 17, 20175:23 pm

    I have done this twice. And I have to say to me it is much easier to just take a small round file and file some notches into the XEON CPU using an old core2 as a template. It is very easy to mess up the pins on the socket trying to get the plastic tabs out of there and you can take your time with the file and do a pretty neat job with not much effort.

    Reply
  • Peter June 19, 201710:57 am

    Confirmed work x3323 with Dell Optiplex XE SSF
    https://www.bios-mods.com/forum/Thread-DELL-Optiplex-XE-SSF-Bios-for-XEON-X3323

    Reply
  • Tina June 19, 20176:02 pm

    Thank you very much for all of this usefull information !

    I am not trying to fit a LGA771 CPU into a LGA775 board, so please excuse my question.

    I want to mod my two (dual) X5365 Xeons with this BSEL in my 771er board.

    1. What can I expect when doing this ? Does this hoover the FSB ?

    2. My board has an Intel 5000x Chipset and my two X5365 Xeons are listed as the biggest
    supported Socket 771 CPU’s. What about the newer 54xx Xeons ( only those for LGA771
    with the same matching FSB ) Do these also fit into Socket 771 and work ?

    Cheers Tina

    Reply
  • Domenico June 22, 201712:48 pm

    Hi to all, i just want to know if Xeon E5472 (FSB 1600, TDP 80W), Xeon X5460 (FSB 1333, TDP 120W) and Xeon E5450 (FSB 1333, TDP 80 W) are compatible with my MoBo Asus P5G41C-M LX (FSB 1333, TDP I don’t know)

    Reply
  • Vegethalia June 23, 20173:10 am

    Hi, tested successfully a xeon X3360 with an Asus P5E3-Deluxe.
    Easily overclockeable to 3.2ghz+ with stock voltajes.

    Thank you!

    Reply
  • atechol June 23, 20174:55 am

    Update:
    HP Pro 3000 MT Pine Row Motherboard Xeon X5450 Mod.
    I posted earlier this week saying this mod was successful and it was. After spending several days loading software (50 games) and all other software. I noticed that the processor was reporting differently on several programs. It would post Xeon X5450 @ 3000 MHz , then showed 2333 MHz behind it. Turns out that the old bios was holding it’s multiplier at 7 instead of letting it run at 9. I followed the instructions for updating the AMI bios here on the site, modded the bios file and flashed it, reset the jumper pin and booted. After resetting my bios settings on the second boot all is well now. For anyone looking for a cheap gaming solution, this combo with 8 gb ddr3 10600, a 450 watt psu and an XFX R7800 Ghost (HD7870) makes for a quite capable gaming machine. You will need to adjust some settings but this lil machine is running Doom, Fallout 4, Skyrim, Sniper GW3, Deus Ex, ETC. Once again thank you to everyone who keeps this site updated and to those of you who have posted your experiences with these mods. I would have never attempted it, let alone completed it, without your help. Thanks Again.

    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.