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.

1,843 Responses

  • na7ane October 9, 20176:14 am

    hello there , I’m thinking about purchasing xeon x5450

    but I’m a little confused , it seems like it’s already modified to run on 775 socket so I don’t have to worry about adapters and such

    but I’m not sure if it’s really as good as q9650 or not , I tried to see if it’s as good or not but it seems like there are no deep comparison on the web

    p.s. I’m buying it for gaming , I’m not saying that I’ll never use it for other stuff , but I want to know what’s better for gaming and gives me better fps

    also I’m not going to oc it , probably .. as I have no experience in doing that + I’m not even sure if my mb can oc it or not

    • Alex2000 October 9, 201710:35 am

      What’s your motherboard? Xeon e5450 is better than x5450. e5450’s perfomace is equal to q9650. For better overclocking results you should buy e5450 with latest stepping E0 (SLBBM).
      Don’t forget to check compability with your motherboard.

      Also check xeon list here:

      • na7ane October 9, 20174:31 pm

        my motherboard is g41mt or something .. it’s not for gaming but that’s what I have .. and I’m almost sure I can’t overclock with this mb

        my budget is around 20 bucks , I’m planing to buy a used cpu .. anything above 20$ I can’t buy .. and as I can see this e5450 costs around 27.50$ so I don’t think I’ll be able to buy it

        so are you saying that the x5450 is bad , or won’t get me good framerates ?

        + is it better to just buy a c2q q6600 or q6700 .. than buying a x5450 ?

        and one final question. in my mb info in official Intel site they say that it works for nm45 .. so does that mean it won’t run a nm65 CPU ?

        • Stepa October 10, 201710:03 am

          What is your motherboard model? Intel G41 Chipset?
          Instead of the E5450, you can buy the E5440. The difference in performance is small, but the price is half as much. In any case, it will be better than the Q6600 / Q6700.

          • na7ane October 10, 20174:14 pm

            I really I’m new to this stuff .. I don’t know much about hardware and such .. so I’m not sure if this is what you’re asking for or not

            my motherboard model name is Intel g41mt-s2pt

            about chipsit .. i googled how to find it .. in device manager/system devices

            I found those 2 lines

            Intel chipset PCI express root port 2E31

            Intel chipset processor to I/o controller – 2E30

            does modified Xeon e5440/5450 work on my motherboard ?

            also I have another question .. what is SLBBM .. and .. SLANQ .. what should I buy ?

        • Stepa October 11, 20171:41 am

          So you have the motherboard Gigabyte GA-G41MT-S2PT? The Xeon e5440/e5450 should work on this motherboard.

          SLANQ/SLANS – C0 Stepping
          SLBBM/SLBBJ – E0 Stepping (newer, it is considered that the revision E0 is better for overclocking)

          • na7ane October 11, 20174:54 am

            yes it’s that model .. thank for the info

            so do I consider that it’s possible to over clock the CPU with this mb , or is it a bad idea ?

  • Alex2000 October 9, 201710:22 am

    I got some issues with my eg43m motherboard (acer aspire m3800/m3802). I know I need to disable c1e. But the option is missing in bios. Trying to find how to add that option.

    Some problems are:
    Installing/loading windows takes forever. It took me about 30 hours to install windows 10.
    Stuttering in games.

    To make windows work good again I need to open registry and change intelppm’s START value to 4 (it’s located in HKEY_LOCAL_MACHINE\SYSTEM\ControlSet\Services\Intelppm) then reboot.

    Does anyone know how to disable c1e in my bios?

    • Stepa October 16, 20179:11 am

      Have you flashed a modified bios?

  • Zé Bandido October 10, 201710:36 pm

    Ive added the xeon microcodes on Gigabyte G41M Combo 1.4.
    I used the Q6600 on 500W PSU.
    Then I installed the Xeon x5470 and first crashed on Windows 10 boot.
    Then after several tryouts, the mobo started to write the BIOS before booting to Windows.
    After the writing I access the BIOS and got a message on MIT saying “…overclocked reversed…”.

    Then I resetted the BIOS through CMOS battery and turn off the PC for several hours.

    After that Ive turn on with a Windows 10 bootable pen and it started installing a new Windows 10.
    It worked until it asked me to reboot the PC, which i did. After that it started to behave as told early.

    Can it be the PSU fault? The Xeon is recognized on post.

    Ps: on PC Health tab i get 76 degrees celcius.

    Is this a faulty microcode issue or else?

    Thank you

  • Giorgi October 11, 20174:37 pm

    HI, I have problem with ASUS P5G41T-M LX3 , I have updated bios 503 with microcode edited and it worked with x5460, but I have update to e5450 and when bios posted it shows “” to unleash this cpus full power update bios” I have already update what should I do, please help me out guys :(

    • Stepa October 16, 20179:02 am

      Most likely in your BIOS there is a microcode for only one revision of processors (stepping E0).
      To fix the problem, just add the missing microcode.

  • benjamin sheriff October 12, 20179:18 am

    E5450 “CO” stepping is working on the MSI PLATINUM COMBO which ant listed on the compatibility section , please add it to the page list!

  • Ccvvzzfg October 13, 20179:58 am

    Ga-ep45-ds3lr xeon e5450 C0 worked.


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.