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 $6 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

2,352 Responses

  • Frank March 24, 20141:11 am

    Has anyone tested the QX9775 yet to see if that processor works as well? My motherboard supports up to the 1600MHz FSB of the QX9770 so I was wondering if this could work as well with this converter.


    • syn March 24, 20141:58 am

      I never knew that was an LGA 771 processor until just now.

      Based on the CPUID of that cpu, it should work if your motherboard’s bios supports the C0 stepping Q9550 (and high TDP processors like the QX9770 or QX9650).

      If your system supports the Q9650 it also probably supports the C0 stepping Q9550, since the Q9650 is newer.

      • Frank March 29, 201412:44 pm

        I have the Asus Maximus II formula motherboard, so it should support the higher TDP of that class of processor.

  • Erik M March 26, 20147:38 pm

    Let me preface this post by stating that I am a novice overclocker.

    X5460 SLBBA cpu running stable on ASUS P5G41T-M LX Plux mobo @ 3.56 Ghz (375.1 X 9.5)

    I was running a QX9650 on this mobo, but due to the FSB (375 max stable in Prime95) and cpu vcore limitations of this mobo, the QX9650 was not reaching it’s potential. I could only achieve 3.6 GHz with the QX9650 due to insufficient Vcore I suspect. So I decided to swap out for a $45 X5460 and try to sell the QX9650 while they are still selling at close to $200 on ebay. With the X5460 I do get a bootup message to “update BIOS to get the full potential of this processor”, but according to the ASUS website I currently have the updated BIOS (V502 10/21/2011). Other than a bootup message, everything runs fine. The X5460 runs a little hotter than the QX9650, but still within design limits. Probably due to the generic thermal paste that I used. Still tweaking this setup as of now, and I may be able to reduce the Vcore with this cpu to reduce operating temps.

    Any tips for overclocking this mobo would be much appreciated.

    • syn March 26, 20148:47 pm

      You can get rid of the update bios message by reading this: https://www.delidded.com/lga-771-to-775-adapter/#update-bios-message. A bios mod to add the exact LGA 771 microcode may even help you to overclock higher, so you may want to try it.

      For the overclocking info, I recommend searching google for “core 2 quad overclocking guide”. A lot of guides come up when I search for that.

  • Ildar March 27, 20144:52 am

    hello if I install xenonE5430 instead intel core 2 e7200 to be noticeable difference in games?

    • syn March 27, 201412:02 pm

      It depends on the game. Some games use more than two threads and some don’t. For games that do, you should notice a difference.

  • Raf March 27, 20141:19 pm

    Here it is:

    As you can see, I called 0803 since the last and latest asus version is 0802.
    I scanned it for viruses already but feel free to check again.
    It’s a .ROM file for P5QL-EM that contains latest bios and microcodes for the LGA771 cpu microcodes.
    Using the “ASUSupdate” facility under windows, select flash bios from file . select that 0803 file and you should be done . Reboot.

  • Manolete March 28, 20145:48 pm

    ASUS Striker II Extreme finally working :)

    Motherboard: Asus Striker II Extreme Rev. 1.02G
    Chipset: nForce 790i ULTRA SLI (C73XE Rev. B1)/(MCP55P Rev A3)
    Max FSB: 1600
    Max TDP: At least 136W
    LGA 775 CPUs Supported: Q9650, QX9770
    LGA 771 CPUs Supported: All
    Xeons Tested: E5472 (SLANR – C0 Stepping) 1600 FSB

    Here is a patched bios for this mainboard (Asus v.1402, last bios for this mobo) with the last intel 771 microcode at the moment.


    PD: I had problems with the instalation of the chip, so be really really careful to properly cut the Mainboard plastic pins, or, as I did, make the new holes in the chip with the right size.

    • meowmix November 16, 20144:12 pm

      hello. is it possible to either email the file or share it somewhere else as the link is dead? does it support the xenon x54** cpu’s in the bios? tia

    • meowmix. November 16, 20146:38 pm

      is there any chance of uploading this to a different server? does it also support the x54** cpus’? tia.

  • Sudos March 30, 201412:42 pm

    Could it be that the reason underlying CPU support could be a sensing pin in the LGA socket sensing the DP support status for the Qxx chipsets vs the E5000 series Xeons? AMD used the addition of a pin to make the dual-processor-compliant Opterons a socket 940 so to be able to be used in a multiprocessor environment– marking the 8xx series 940’s as able to be used in quad-CPU environments. however the 8xx series quad-CPU chips could be used in a dual-socket board without any issue whatsoever.

    it makes me wonder if the same thing is happening here with a sensing pin those Qxx chipsets have.
    Has anyone looked into this yet, and tried to just add the proper microcodes to the BIOS to support them anyway and then try it regardless?

    • syn March 30, 20144:04 pm

      Yes, it’s definitely possible that’s what’s going on here, and there may be a way to get around it, but I haven’t heard of a way yet.

      People have tried adding the Xeon microcodes to the bios to get 5xxx series to work on these chipsets, but it didn’t work.

  • mike April 1, 20144:41 pm

    hi syn i just been looking around about this bsel mod on the 775 skt motherboards
    its basicly a mod of the cpu getting a peice of copper tape and connectiing to point together making the computer run in a higher fsb could this possibly still work after i put a X3363 skt in??? if not i can try it and let you all no?

    • syn April 1, 20145:30 pm

      Yeah, it should still work, since all of the pins related to fsb should be the same.

  • gagarin77 April 6, 20149:35 am

    @ mike – no, don’t do that! This mod isn’t about shorting those two pins, it is about swapping them! Use a proper adapter, they are cheap and easy to obtain.

    • syn April 6, 20141:52 pm

      I think that Mike was talking about doing something else (not shorting the two pins swapped by this adapter).

      There’s another mod for increasing the FSB of your motherboard if you don’t have a bios that allows overclocking.

  • sparticle April 6, 20149:43 am

    Asus Striker II NSE – latest bios 0901 modded for Xeon

    Not stable with Xeon chip, tried 2 different chips L5430 & E5450 both work in other boards.

    POSTs and boots fine, then random reboots, BSOD, lock ups etc.

    Not recommended despite chipset being marked as compatible. Tried both windows and linux.


    • sparticle April 6, 20149:46 am

      Forgot to mention board works great with a 775!


    • syn April 6, 20141:57 pm

      Have you tried resetting the bios through the jumper on the motherboard or by removing the CMOS battery? Have you also loaded the default settings in the bios after installing the Xeon?

      These things usually fix random reboots, BSOD, and lock ups if you’ve already added the Xeon microcodes to your bios.

      • sparticle April 6, 20146:10 pm

        Yes, tried all of those things. I normally start with a full reset bios to failsafe. then cold boot. Checked seating of the chip a couple of times and happy with it. Works perfectly in other boards.

        Just flaky, sata issues, network issues, CPU lock ups. everything detected perfectly all features enabled all looks good. But just unstable. Very difficult to debug, as even kernel logs just stop with no waring, immediate reboot. Comes back up fine. Very frustrating.

        Anyway abandoned in favour of Gigabyte P45 chipset board. Which is rock solid with the same chips.

        GA-EP45C-DS3R (rev. 1.0)
        Intel® P45 + ICH10R Chipset

        Latest EP4CDS3R.F6a Bios modded with x0b codes for the 1067a processors.



        • syn April 6, 20147:47 pm

          Thanks for letting us know. I haven’t heard of any other problems with the 790i chipset, so I’m hoping this was an isolated incident with your motherboard, but I’ve removed the 790i from the compatible chipset list for now, and I’ll keep an eye on it.

  • weazelbeater April 6, 20143:13 pm

    I’m eyeing a Xeon X5460 for a cheap upgrade: is there any reason why a C0 vs. E0 stepping should matter? This is for a GA-EP35C-DS3R (rev. 2.1) that I already know runs an E5450 C0 stepping perfectly (which will be moved to another board that can’t go any higher than E5450). My research shows that E0 change is just this: “Changes in E0 stepping: new XSAVE and XRSTORE instructions, ACNT2 feature used for determining processor utilization, halide-free package.” I think it probably won’t matter, but I figured I’d ask anyways. Also, I’m wondering if 771 sellers are catching on to this particular trick: I now can’t find an X5470 for really cheap prices anymore. Anyone else notice higher prices recently?

    Other query (purely theoretical): Xeon ES chips seem to usually have unlocked multipliers…would this allow for significantly higher overclocking, or are ES chips inherently more unstable?

    • syn April 6, 20144:03 pm

      E0 is newer and seems to overclock better, but some systems don’t support it (it should work if your system supports a Q9650).

      Yeah, the prices have definitely gone up some due to this mod.

      I’m not sure about the stability of the engineering sample cpus, but it should definitely help you overclock higher if you’re limited by the fsb your motherboard can do. Many P35 motherboards can only hit a little above a 400fsb, while the P45 can do much higher.

    • SingleDad April 6, 20144:09 pm

      I was shopping for the same processor about a week ago. I can definitely tell you sellers have caught on and aren’t letting the Xeons go cheaply. I too was looking at the X5470 and couldn’t find one at a price that made sense for updating a dated rig. $75 to $100+ seems a little steep for a used processor that’s 8 years old. After a few days of searching I gave up on the X5470.

      I chose the X5460 because it was more available and the prices were more reasonable for a used CPU. I decided there wouldn’t be a huge noticeable performance difference between the two for me. On fleabay there were a few sellers that had multiple Xeon X5460’s with a “Best Offer” option. Thinking these guys with a handful of these (probably pulled out of scrapped servers for free) would be willing to budge on price proved to be comical. I put in a few different very reasonable offers for a X5460 from a few different sellers. Let me tell you they don’t budge on price. Many of them were $65+ and I’d offer around $45 to $50. Still fair with room for the inevitable counter offer from the seller. Two of them counter offered for like $3-5 less than their full asking price. The other just flat out declined my offer. The sellers (at least on ebay) aren’t budging an inch and the price just seems to keep rising. Your best bet is to search more locally or if you have time to spare just wait for the rare lucky steal on ebay. There’s always someone who doesn’t know or who will under-price to move it fast. The problem is all of us waiting for the same person! ;)

      • Mark Owens April 13, 20149:34 am


        Very true! Just a few months ago I purchased E5440s with relative ease for $26, E5450s for under $37, and the even faster X3363s for under $35 on eBay!

        While E5450s can still be found for around $40 each if you buy them in pairs on eBay–you would be hard pressed to find any E5440s for anywhere near $26–and completely down on your luck in finding X3363s for anywhere near $35 because of the limited supply of X3363s and the realization that the X3363 is one of the fastest Xeon CPUs that will work in an LGA 775 board. I’m kicking myself because just 2 weeks ago, a pair of X3363s were auctioned of on eBay for $76.49–a steal considering these CPUs sell for approximately $75 each.

        Thankfully I stumbled across this delidded site and purchased the all the Xeons I needed before demand would outstrip supply and drive up prices.


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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.