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



Motherboard Compatibility

There are two requirements that your motherboard must meet in order to be able to run LGA 771 Xeon processors:

  1. You must have an LGA 775 motherboard with a compatible chipset.
  2. Your bios must support an LGA 775 CPU that's similar to the Xeon you want to run.

We'll explain how to verify these things in the sections below. And later in this guide, there's also a list of motherboards that have been tested with this MOD.

First, make sure your motherboard's chipset is compatible

The chipset we're talking about here is technically called the Northbridge chipset. You can usually find what chipset your motherboard has by looking at its specification list.

Chipset compatibility table

Note: For known compatibility issues and more details, please see the bullet points (which are shown right after the table).

Xeons that are compatible with each chipset
Chipset5xxx Series3xxx Series45nm65nm
P45, P43, P35, P31, P965
G45, G43, G41, G35, G33, G31
nForce 790i, 780i, 740i, 630i
GeForce 9400, 9300
Q45, Q43, Q35, Q33
X48, X38
nForce 680i and 650iYesYesMaybe
(see below)

If you don't need more details about the topics shown above, you can skip ahead to the next section: Next, make sure your BIOS supports a similar LGA 775 CPU.

What do 5xxx series and 3xxx series mean?

By 5xxx series we mean any Xeon whose model number ends in 5xxx (this includes all the E5xxx, X5xxx, and L5xxx processors).

Issues with Intel brand motherboards

Note: This information only applies to motherboards actually manufactured by Intel. We haven't heard of any problems with ASUS, Gigabyte, MSI, or any other brands.

Some motherboards made by Intel don't work with this mod

For some reason, some Intel brand motherboards that have a compatible chipset and support a similar LGA 775 processor do not work with this mod (please see the list of tested motherboards for the model numbers).

It may not be possible to update the CPU microcode on an Intel brand motherboard

This is sometimes needed to install Windows 8.1 64-bit or to enable all of the CPU features (like Speedstep, SSE 4.1, or VT-X). The older non-E0 stepping processors often don't need a microcode update to enable these features, so if you do try it, buy one of those.

The reason this may not be possible is because Intel has their own proprietary BIOS that nobody currently knows how to MOD (even by manually hex editing the BIOS).

Nvidia's nForce 680i and 650i chipsets don't officially support 45nm quad core processors

Some motherboards with these chipsets have worked with 45nm quad core Xeons, and some haven't (please see the list of tested motherboards for more details). This is likely due to some motherboards unofficially supporting 45nm quad core processors.

My chipset isn't listed here. Will this work for my motherboard?

The mod will still likely work if your BIOS supports a similar LGA 775 processor.

If you do try it, please let us know how it goes by leaving a comment at the bottom of this page.

Our guess as to why some chipsets don't support the 5xxx series Xeons (but do support the 3xxx series)

Xeons with model numbers that end in 5xxx are allowed to be used in motherboards that support 1 or 2 physical processors (this is called dual-processor support). However, the 3xxx series Xeons cannot be used in a multi-processor system (they're labeled as supporting uni-processor configurations only).

The E0 stepping E5440 and X3363 Xeons both have the same CPUID (1067A), which means they're both made from the same silicon and are basically the same internally. Additionally, there's no noticeable difference between them (other than one has dual-processor support), so it looks like this could be causing the problem. Some chipsets may be checking for this and may be blocking the system from booting.

Next, make sure your BIOS supports a similar LGA 775 CPU

Important: Make sure you only buy Xeon processors with a FSB and TDP supported by your motherboard.

How the compatibility table shown below works

Hopefully the table shown below is pretty self explanatory, but here's an explanation if it isn't. Each row shows an LGA 775 processor in the 1st column. If your motherboard and BIOS support that processor, you can run the LGA 771 Xeons shown in the second column (if your chipset supports it).

You should only buy Xeons with a FSB and TDP less than or equal to the values shown (unless your motherboard supports higher).

If your motherboard and BIOS support the following CPU:You can run these Xeons (if supported by chipset):Max FSB
(unless motherboard supports higher)
(unless motherboard supports higher)
Core 2 Quad Q9650Any 45nm quad core Xeon133395WView Xeons
Core 2 Quad Q9550SAny 45nm quad core Xeon with a TDP of 65 W or lower133365WView Xeons
Core 2 Quad Q6700Any 65nm quad core Xeon106695WView Xeons
Core 2 Duo E8600Any 45nm dual core Xeon133365WView Xeons
Core 2 Duo E6850Any 65nm dual core Xeon133365WView Xeons

For a list of all the compatible Xeons, their features, and current prices, visit this page.

If you don't need more details about the topics shown above, you can skip ahead to the next section: Recommended LGA 771 Xeon processors.

Some Xeons have a higher FSB or TDP* than their similar LGA 775 CPU

* TDP is a measure of how much heat your processor's cooling system will have to handle.

Because of this, you need to make sure your motherboard supports the FSB and TDP of the Xeon you're buying. Some motherboards will not boot processors with a TDP over 95W (or 65W for low power boards).

TDPs for some common Xeon processors
  • L54xx series has a max TDP of 50W
  • E54xx series has a max TDP of 80W
  • X54xx series with a 1333 FSB has a max TDP of 120W
  • X54x2 series with a 1600 FSB has a max TDP of 150W

How to check what TDP your motherboard supports

Our list of tested motherboards (shown later in this guide) has max TDP numbers for many motherboards, so you should check there first.

If your motherboard isn't in our list, a good way to check if your motherboard supports 120W and above processors is to check its CPU support list. If your system supports overclocking or extreme edition processors (like the 130W QX9650), you should be able to run the 120W X54xx series Xeons (the 150W ones will also probably work). However, if your system only supports the 95W Q6600 with a G0 stepping (and not the 105W B3 stepping), your system may only supports 95W and lower processors.

If you aren't sure what TDP your motherboard supports, I'd recommend going with the 95W and lower Xeons only.

How to check what LGA 775 processors your motherboard supports

If you're unsure what LGA 775 processors your motherboard supports, please read the following article: How to Check if Your Motherboard Supports a Specific Processor.

Be careful if you have a prebuilt system (like a Dell)

Prebuilt computers (like Dell) sometimes use different motherboards (depending on what parts come with the system), and the motherboards may not support the same processors, so you'll need to figure out which motherboard you have.

You should be able to find the model number with CPU-Z.

Right now, the following 45nm Harpertown Xeons with a 1333 FSB seem to be the best deals. These are quad core and have high multipliers (ratios), which means they should also overclock easily.

For more prices and detailed specs on all of the Xeons, visit this page.

2,019 Responses

  • DaniV March 28, 201811:21 am

    Hello, I buyed intel xeon E5440 SLBBJ (E0) from aliexpress for my Pegatron IPMEL-AE motherboard with G41 chip but couldn’t make it work properly.
    First i tried to install it without microcode update since i have G41 chipset but it just got stucked on the initial BIOS screen and didn’t enter neither the BIOS or windows.
    Then i updated the microcode via afudos and (after removing the battery of the BIOS and reset it to default) was able to enter the BIOS, wich recognised the processor but once i tried to enter the system the loading screen was laggy and after a while (MUCH longer than it takes to boot the system) it showed me a blue screen with the error code “DPC WHATCHDOG VIOLATION” wich seems to be probably hardware incompatibility.
    I saw on some comments that some processors doesn’t work with E0 stepping but they do with C0. Does anyone with a similar motherboard know if it can be related to that or if there is any solution?
    I will be very thanfull with any help you can provide me :).

  • OliKa March 29, 20185:28 am


    I tried mods with three Motherboards lately using XEON E5450 SLBBM (Stepping A Revision E0).
    Hopefully I can help updating the motherboard list.
    On all the motherboards I used microcode upgdated bioses from http://genius239239.myweb.hinet.net/771/

    1. ASUS P5N7A-VM

    – “Intel C-State tech” MUST be disabled!!!
    – C1E can remain enabled!
    – stable for more than 24 hours

    When enabling C-state booting Win10 and Linux will be slowed down extremely (like 20 minutes or so to login)


    – works like a charme, all available C-state settings enabled
    – stable for more than 24 hours

    3. Gigabyte GA-E7AUM-DS2H

    – very unstable!
    – playing with c-state settings doesn’t improve stability
    – sudden hard restarts (without bluescreen) between running time of 15 min. to max. 3 hours
    – checked with 2 XEON CPUs – same result
    – works well with Core2Duo E8400, so the motherboard itself is most likely okay
    – failed with this XEON E5450 E0

  • GRX April 1, 20182:12 am

    Have had this working for a year no issues in my Gigabyte Motherboard (previously listed).
    However, someone trying this may want to be careful about temps. I installed this E5450 in my machine just using the original Core Duo heatsink fan and some new arctic silver.

    According to both the hardware temp monitors I have installed I’m idling at 58C on the cores and SURGING up to 95C at load. CPU reading is at 42C under load.

    If this core reading is accurate, I’m surprised the CPU hasn’t exploded. But, unless a replacement heatsink and fan is really Cheap, it isn’t worth it to invest anything else into an obsolete system (just the CPU swap is getting questionable at this point).

    Just thought I’d throw that out there. Apparently, you can’t take it for granted that you can run this Quad Core even at stock at a reasonable temp using Core Duo cooling.

    • GRX April 5, 20187:28 pm

      I think this is resolved. Some of the issue ended up being that the temps were reported somewhat inaccurately high. Although, even discounting that, the temps were still way too high.

      the main issue ended up being the Intel heatsink and fan. At least one of the plastic pins which is supposed to mount it to the board had broken off, allowing the heatsink to ride up on a corner.

      This Intel cooler is a real POS. I ended up removing the motherboard, ripped the pins out of the heatsink/fan and bolted it to the board using thin bolts, nuts and thick rubber gasket washers.

      After, temps at idle have dropped to around 40C and around 60C at max.

      That should do it- for non-overclock

  • ShohS April 1, 20185:19 am

    MSI g41m-sp20 works with E5450 (E0) (xeon microcode applied)
    MSI p31 neo v2 works with E5430 (C0) (xeon microcode applied)

  • Vince April 4, 20184:46 am

    Vostro 220 board with xeon microcode bios update doesn’t boot with an E5472

  • Rafael Costa Ferraz April 12, 20183:21 pm

    Hello friends, as I was recommended, I placed the intel xeon 5450 on my motherboard striker extreme chipset 680i, but when I updated the bios of her with the file 771 of this link that I was indicated (http://ideafix.name/stuff/Striker -Extreme.zip)
    My computer does not start ….
    (Note, it does not even start with my old processor)

    Please, friends, I need help …

  • Greensmack April 15, 20189:39 am


    I wanted to report that I have an Asus P5W DH Deluxe motherboard running on a Xeon 3370; clocked to 3ghz per core with an FSB set to 300mhz.

    Depending on the video card installed, and if PEG is enabled for the video card, the FSB can go as far as 315mhz before encountering BSODs in windows. (PEG is a PCIe bus performance booster that also can affect any PCIe peripheral cards, too; like SATA or NVMe adapters/controllers for PCIe slots).

    To get the 3370 to work properly, the same bios I had previously was simply reflashed back to the motherboard.

    I did not have to update the microcode of the bios rom itself, although I wouldn’t advise against it; I just wanted to report that the latest public release for the P5W DH Deluxe works with the Xeon 3370; bios messages about the microcode go away if the same bios is reflashed back into CMOS.

    (I just wish 64-bit PCI-X functionality could be introduced the same way!)

  • bart April 17, 20185:02 pm

    ASUS P5K-VM works generally with a X5470, but i get during booting the folowing error mesagge:

    ERROR! The CPU Core to Bus ratio or VID configuration has failed!

    will try a stronger Power supply tomorrow…

    • bart April 19, 20186:05 pm

      700W Powersupply did not help,
      System is running stable but i do not have the full perfomance (~3900 CPU Mark Score instead of ~4600)

      Microcode update has been processed, BIOS resetted… any hint ?

  • JJ April 21, 201811:53 am

    Just came here to say that the ASUS P5QL-EM works, seems by the model number it’s the same series as the P5QL-E plus the specs are similar, and the 5450 Xeon that I used is compatible with both motherboards

    Gave a 10 second countdown, flashing microcode update fixed it, the user interface of the bios modding program could be designed better tbh


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.