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 $16 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

2,264 Responses

  • Todd March 6, 20189:18 pm

    Any help would be appreciated from anyone who can provide it.

    I am using a very old c2007 Dell XPS 720 (mobo YU822, chipset 680i SLI C55XE Rev-A2).

    I currently have a QX6800 I’m stably overclocking to 3.7GHz on the massive air cooling heatsink that came stock with the system in 2007. However, it will run hot into mid to upper 70s under load (such as when playing Witcher 3) and I don’t want to prematurely burn out the CPU. Inspired by all of this Xeon 771-775 craze, I found a modded X5460 SLANP for like $30 on ebay and figured what the heck. While this CPU was not officially supported by Dell’s latest BIOS version (A06), the Xeon 5460’s TDP, Voltage range, FSB, and C0 stepping are all supported by this mobo/BIOS. This motherboard did not ever have support for E0-stepping CPUs. This motherboard did have official support for some 45nm CPUs as well (Q9450).

    With the Xeon X5460 in place, I am able to post, and boot windows, but will experience random reboots usually within minutes once Windows is running (not overheating according to Coretemp). When I first installed the CPU it ran fine in Windows for about half an hour but Windows hardware added drivers (I assume for the CPU?) and requested a restart….and the random rebooting began occurring after that event.

    I assume there is some CPU feature (SSE 4.1, etc) that the motherboard isn’t utilizing correctly with Windows since it posts and boots Windows most of the time (sometimes it reboots before I hit the Windows desktop). I’ve tried turning off Virtualization, C1E, Speedstep, EPP/SLI, etc within the BIOS and nothing seems to improve the random reboots. The Dell BIOS is limited in what I can mess with (no voltages, etc). I’ve run the system in Safemode which lasts longer but reboots have still happened. When I put the QX6800 back in, everything is great again.

    It is possible the CPU I bought used off Ebay is trash despite supposedly being pulled from a working machine by the seller. However, given that I am putting it into a motherboard that never technically supported it I have to assume the issue is on my component’s end.

    I have tried to modify the most recent Dell XPS 720 BIOS revision (A06) according to the directions on this site.
    I am able to extract the “XPS720-A06.rom” file from the Dell official “XPS720-A06.exe” BIOS update file as directed.
    I am able to combine the two bin-files (cpu00010676_plat00000004_ver0000060f_date20100929 & cpu00010676_plat00000040_ver0000060f_date20100929) for the Xeon X5460 using command prompt.
    However, when I use CBROM195 to add the microcodes to the extracted BIOS ROM file using command prompt, nothing happens. Even when I’m just checking the BIOS ROM with the “cbrom195.exe XPS720-A06.rom /d” command, it just shows the CBROM version info (“cbrom195.exe V1.95 [12/14/07] (C)Phoenix Technologies 2001-2007”).

    I am not sure that I have the PC savvy to mess with a Hex-Editing software. I’m honestly kinda at my limits with what this website has instructed me to do. I am afraid I am going to brick my motherboard and the whole reason I am trying to get this Xeon upgrade is because I don’t have the money for a whole new system right now and I’d like to squeeze a few more ounces of juice from this system until 2019. Xeon CPU seemed like a cheap option for a few extra FPS.

    Sorry for the very long message.


    My system:
    Dell XPS 720 (mobo YU822, chipset 680i C55XE rev A2)
    QX6800 (trying to get X5460 SLANP to work)
    FSB at stock (1066Mhz for QX6800, 1333MHz for the X5460).
    8GB DDR2 Corsair XMS2 PC2-6400 800Mhz (5:5:5:18) EPP RAM.
    MSI GTX 750Ti 2GB OC edition (stock speeds)

    • Goran Jankovic March 8, 20185:19 pm

      I will look into it tomorrow, gonna msg you here when I’m done.

    • Goran Jankovic March 8, 20185:24 pm

      also, 70c for a dual core seems like too much to me. I have e5440@3.4GHz, 1.26V (stock 2.83GHz), and it never goes over 65 with this cooler.

      • Todd March 8, 20188:22 pm

        Thank you VERY much for your response!

        The G0 stepping SLACP QX6800 temp range is up to 65C according to Intel website. Mine under typical load at Bin+3 doesn’t get above this. With high load, it gets into 70s on Coretemp and AIDA64 shows temps never getting above 70C. Assuming the average of Coretemp and AIDA64, my peak CPU temps are 70-72 which is a bit high, but only 5-7C above rec temps. Based on what i ve read this could shorten the life of CPU, but to years not months. l usually run it at Bin+2, actually, which peaks below 70 on both temp measuring systems.

        In the last couple of days I have tried opening the Dell “XPS720-A06.rom” file I extracted from the official Dell BIOS (in .exe format). None of a variety of BIOS editing software I tried seem to be able to read it….It’s not just Cbrom195. I am suspicious the “/writeromfile” command isn’t actually extracting the ROM file. Maybe someone on here with mote specialized software could extract that Rom from the official Dell BIOS .exe file??

        • Goran Jankovic March 15, 20189:45 am

          sorry for not responding earlier, I’ve been busy (lies, I forgot about this ;D). After some trying and digging, it appears that Dell uses a different BIOS layout than usual. I am currently trying the mod using a different tool than CBROM, gonna msg when I’m done

          • Todd March 15, 201810:15 am

            Thank you so much. If you’re able to extract the xps720-A06.rom and add in the X5460 microcode, could you please add the QX9650 as well?…I found one cheap on eBay and am going to try it too when it arrives. Whichever one of those 2 CPUs runs faster /overclocks more stably I’m going to keep and flip the other on EBay again.

          • Goran Jankovic March 15, 201810:25 am

            what’s the sspec number of the qx9650 you want to buy? it’s one of these> Q7UE, QEFX, SLAN3, SLAWN, important ’cause of the cpuid

        • Goran Jankovic March 15, 201811:51 am

          my previous question:
          what’s the sspec number of the qx9650 you want to buy? it’s one of these> Q7UE, QEFX, SLAN3, SLAWN, important ’cause of the cpuid

          also, CBROM and intelmicrocodelist tools work fine with a gigabyte bios file, so it’s a problem with the particular dell bios file we’re trying to mod. I was able to extract the bios modules using PhoenixTool, but now I need to find out how to update the microcode. That’s how far I’ve gotten :D Gonna update once I hopefully get further

          • Todd March 15, 201812:02 pm

            Thank you so much again for your help. This level of editing stuff is beyond me.

            I ordered the SLAWN (C1 stepping) QX9650. My mobo has official support for other C1 stepping CPUs, but no official support for E0…I’d read with C0 CPUs the fans just run 100% all the time because the stepping isn’t recognized.

          • Todd March 25, 20186:30 pm

            Any luck with this per chance? My QX9650 arrived and I can run it stock, but I can’t adjust the multiplier because my BIOS doesn’t recognize it as an “Extreme”.

            Thanks again!

        • Goran Jankovic April 3, 20187:51 pm

          Sry for not responding earlier. I had no luck finding a tool to mod the bios. None of the tools I found would open the bios properly. I was able to unpack it into modules using PhoenixTool, but I don’t know how to proceed since I don’t know which one of the modules contains microcodes.

          • Todd April 4, 20188:57 am

            No worries. Thank you so much for trying. Clearly Dell locks their BIOS down hard. The QX9650 I got off Ebay works really well (seems to have really made a diff in CPU bottleneck in Witcher 3). Unfortunately I cannot overclock it in BIOS or Ntune (crashes), but seems completely stable and compatible with my system at stock speeds. I found an old Dell OEM water cooling system I’m going to try and refurb myself which may allow higher overclocking with the QX6800 or QX6850 I have laying around too.

            Perhaps Rivatuner or another will allow me to software overclock the QX9650.

  • Pawel March 8, 20181:20 am

    Xeon X5460 on GA-EQ45M-S2 rev 2.1 – not working. Tested with BIOS FC and FD. Added Xeon microcode to BIOS – don’t work.
    LGA 775 support – tested – QX9770.

  • Simpson March 8, 20186:56 pm

    Foxconn G31MXP does not work. Tested with E5430 and L5420.

  • Simpson March 8, 20187:04 pm

    GA-73UM-S2H works with E5430. L5420 booted but OS does not load.

  • Dominique March 9, 20187:33 pm

    Gigabyte GA-P35-DS3 works with E5458.

    I use the BIOS from the manufacturer (release F14).

    The machine runs Linux.

  • miknunoob March 10, 20184:41 am

    Fujitsu d2950 board works with x5460, windows etc didnt boot until i added microcodes via FreeDOS


  • Anatoliy March 10, 201811:51 am

    Add to the table the board Biostar G31-m7 TE ver.6.1, L5410 (C0). The BIOS is not modified. BIOS supports stepping C0

  • Jonas March 12, 201811:39 am

    Can confirm X3323 finnally worked after replacing ALL the microcodes on the bios file! Thanks

  • Jonas March 13, 201810:59 am

    I have noticed now my mouse arrow has a delay or lag occasionally, anyone has experienced the same issue?

  • Mehdi March 14, 20188:15 am

    I’m looking to know if a intel xeon E5450 will work on my ECS MCP73VT-PM motherboard , it has a 620i chipset (geforce 7050)

    There is the same motherboard but with a different name if you want ; ecs gf7050vt-m5

    I already bought a X5460 but it won’t work because it has a too big TDP , i didn’t tried to put but if it work , i’ll simply buy a lower tdp E5450

    Thanks in advance. (sorry for my poor english)


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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.