Guide for Haswell-E 4GHz+ Uncore

First of all I want to thank GIGABYTE. I had the possibility to bench at their OC Lab in Taipei, Taiwan for one week. Without their resources (CPUs and motherboars) I would not have figured this out. Thanks a lot guys especially Sofos and HiCookie!

NOTE: This is all based on some reverse engineering and experimenting. I’m just reporting what worked for us and giving you advice. This modification was tested on three different Core i7 5960X CPUs and different mainboards. Nothing died even after applying some ridiculous voltages. However, I can’t guarantee nothing will go wrong. In addition I have no idea how this could affect the lifespan of your chip. In other words: All modification on your own risk!

I tested this modification on the normal X99-SOC Force (without OC-Socket) and on the LN2 version with OC-Socket. It works on both boards without burning anything. However I can’t guarantee that it will work on all boards from other vendors. It would be up to you guys to test and approve this. I’m pretty confident that it will work though.

So in order to achive higher uncore clocks we have to modify some of the CPU voltages. This means we have to mod the CPU. Yes – talking about modding a USD $1,000 processor. There are two ways how to do this. The first way is the “lazy solution” and depending on your chip and board you should be able to run 4000-4200 MHz with this mod. For everything above you have to step up to solution two.

Basic explanation

I was trying to find the difference between the OC-Socket and the normal LGA2011 socket. So I just took the X99-SOC Force (no OC-Socket) and the X99-SOC Force LN2 (with OC-Socket) and measured the differences between the pins. After that I soldered thin wires to the empty pins of the CPU and measured the voltages while it was running. I came across two additional voltages which are not supplied on the normal socket, but are present on the OC-Socket. However the CPU internally supplies itself with different voltages there.

Taking a look at this graph you can see that there are actually two Ring Bus inside the CPU. The voltage we have to change is the “Interconnect Bus voltage” which basically connects both Ring Bus.




The key is to get both of these to the same level and increase if you need even higher clocks.

  • Pin 1 (Interconnect Bus voltage): 1,075 Volt on stock
  • Pin 2 (QPI Bus external voltage): 1,350 Volt on stock



The 4G-Lazy-Mod

A lot of boards out there seem to have a wall at around 3600 MHz to 3700 MHz. To bypass this wall we have to get the both supply voltages to the same level. So just connect both pins on the CPU which will result in a voltage of about 1,260 Volt. This should be fine for 4000 to 4100 MHz according to my testing.

The connected pins will be above this little area on the normal socket. Make sure you keep the mod as small and thin as possible. The CPU directly fits on the piece of plastic once you push it down by the mounting mechanism. If it’s too high it could be that not all pins touch the CPU anymore.


I soldered directly on the CPU. Please only do this if you are already experienced in soldering. Otherwise it could happen that you connect more pins and kill your chip.
I suggest that you cover the rest of the pins while soldering. Here at the GIGABYTE OC Lab we had some special soldering tape that is temperature resistant and doesn’t melt. No clue how this is called exactly or where you can find it but this makes the mod very easy to apply.


Another solution would be to use some kind of silver conductive paint but I didn’t test this myself.

The 4G+ Mod

The things you need:

  • Soldering iron
  • Soldering tape
  • Small wire
  • External power device such as GIGABYTE G-Power
  • Multimeter
  • Soldering experience

4 GHz might be cool on the uncore but I think we all are aiming for 4500-5000 MHz on LN2, so for this we need to raise the Interconnect Bus voltage and QPI Bus external voltage. It’s not that easy to just apply a voltage to a CPU with no pin available at this position in the socket. So I grabbed one of my favorite external power devices (GIGABYTE G-Power-Board!) and connected it to the pins.

To get the mod working you have to connect both pins like in the lazy version and add a wire at the same time. Take a very thin wire and solder it to the pins. Also here it helps a lot if you have this special soldering tape to cover the rest of the CPU. I measured the current flow in circuit of this mod and it’s usually between 25 mA and 80 mA so a thin wire is no problem at all.


Now carefully place the CPU in the socket and close it. Take a measurement device and check the resistance from the wire to GROUND (anywhere on the board). On all CPUs I tested I had a resistance of 15,4 Ohm to ground. Of course this might vary depending on your multimeter but the value should be around this. If it’s far off like 2 Ohm or even 1 kOhm take the CPU out of the socket and check the mod if you connected a third pin or the wrong pins.


If the resistance is fine connect this wire to the V1 area of the G-Power-Board. Connect the ground area to any ground of your mainboard. I suggest to use a ground close to the CPU and not e.g. a 4-Pin molex of your PSU. An easy way is to use the voltage measurement area of the mainboard. I used one of the measuring cables and connected the ground there. It’s handy because you can just plug it in and out which disables/enables the mod (keep in mind that the two bridged pins are still fine to go to 4000 MHz even if the 4G+ mod is disabled!).


If you have a different external power module it’s fine as well. Just make sure the stock voltage is around 1,20 Volt and you can go up to 1,70 Volt in small steps. Since we are talking about a load of not even 0,1 Watt you don’t need a strong power device.

Another idea is to hook this voltage up to a different supply voltage from the motherboard. A good approach is the DIMM voltage since you can start at 1,2 Volt on DDR4 without issues and also go up to 1,70 Volt on LN2.

If you turn on your system make sure the voltage of your G-Power is at about 1,2 – 1,25 Volt. This will be fine to do any kind of tuning in the BIOS and usually around 4000 MHz uncore frequency.

To get higher clocks you have to test a bit and find the right voltages to boot and run for your CPU. Also not sure how it will be on other boards than GIGABYTE but should be similar.

Since all chips differ a little you might need to find the right voltages. This is a workaround which worked for Sofos and me. You can use this as a guide at the beginning. Once you find the right voltages you can usually skip the steps 2-5. We managed to boot directly to windows with 4125 uncore. We always used the 125 BCLK strap.

  • 1. Set a low uncore like 3000 MHz and apply all other settings you need such as voltages, features and memory.
  • 2. Apply and go back to bios.
  • 3. Raise the uncore to a higher level which you know was stable without the mod (we always used 3500 MHz) and apply. Check that the system does not power off after you changed the uncore. Otherwise it will be much more difficult to do this.
  • 4. Apply and go to bios
  • 5. Raise the voltage while you are in bios to about 1,40 and apply the voltage
  • 6. Change the uncore multi to the level where you experienced the wall before applying the mod. We set to 3750 MHz uncore
  • 7. Apply. It should now reboot without shutting down.
  • 8. Boot into windows with 3750 MHz
  • 9. Apply 32x uncore (4000 MHz)
  • 10. If you want to go higher just raise the uncore support voltage and keep testing what works for your chip.

We could do 4500 MHz uncore at about 1,55 Volt on air. 1,70 volt was fine for about 4700 MHz uncore on LN2. Don’t forget to change the normal uncore voltage in your bios though. It’s a completely different voltage and not related to the QPI and Interconnect voltages we are talking about in this guide! You still have to increase the normal uncore voltage in order to reach high uncore clocks.


Tested and confirmed with 3 different 5960X CPUs. I’m not sure how/if it works on the 6-Core Haswell-E and other motherbords but I think it should be the same. However I suggest to not apply this mod on CPUs if you use them on boards with OC-Socket such as ASUS R5E.


  • 5960X – 4500 MHz 1,525 Volt (4G+ Mod)
  • 5960X – 4500 MHz 1,57 Volt (4G+ Mod)
  • 5960X – 4125 MHz 1,26 Volt (4G-Lazy Mod)
  • 5960X – 4500 MHz 1,26 Volt (4G-Lazy Mod)


  • GIGABYTE X99-SOC Force rev 0.2 (4G+ Mod)
  • GIGABYTE X99-SOC Force rev 1.0 (4G+ Mod)
  • GIGABYTE X99-SOC Force rev 0.2 (4G-Lazy Mod)
  • GIGABYTE X99-SOC Force rev 1.0 (4G-Lazy Mod)
  • GIGABYTE X99-SOC Force LN2 rev 1.0 (4G-Lazy Mod)
  • MSI X99S XPower AC
  • ASRock X99 OC Formula


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