LGA1366 Overclocking Guide¶

Understanding Socket 1366¶

Clocks¶

Socket 1366 is a platform that mostly relies on base clock overclocking. This means that rather than relying on multipliers (which often have a limited range, especially on xeons and non-X i7s which don't allow multiplier OC), most overclocking is done by changing a single base clock speed.

The 133MHz base clock on Socket 1366 affects;

• CPU Core

• Memory

• QPI link - the link between the CPU and the X58 chipset

• CPU Uncore - the bits that aren't the core, notably the memory controller

Separately there's the PCIe clock. PCIe is important when you're pushing 220mhz+ base clock, as the platform has trouble when base clock is too far from PCIe. /u/ground15 has found a rough formula of (BCLK-221)*0.445+100 for minimum PCIe. To give a few examples:

Increased PCIe above the minimum needed may still help a little at lower speeds. High PCIe can cause issues with storage and GPUs, so this is mostly relevant for extreme/competitive overclocking.

The other relationship between clocks is that Uncore has to be at least 2x memory data rate - so for example DDR3-1600 requires at least 3200MHz uncore.

Jargon¶

Socket 1366 has some odd jargon that's peculiar to the platform;

Reference Clock/BCLK - The base clock that affects core, uncore, memory and QPI.

FSB - FSB doesn't technically exist on 1366 (there isn't a Front-Side Bus), but the term FSB comes up in conversation with experienced overclockers and on old forum posts so it's important to be comfortable with it. In the context of this and other modern platforms, FSB means the same thing as BCLK and can be used interchangeably.

IOH - I/O Hub, a name for the X58 northbridge. The IOH provides a large number of high-speed (for the time) PCIe 2.0 lanes for GPUs and such, and a DMI link to the southbridge.

DMI - Intel's name for their link to southbridges. Basically PCIe x4.

ICH - I/O Controller Hub, a name for the southbridge. The ICH provides SATA, USB, a small number of PCIe lanes for x1 slots, and miscellaneous low-level stuff like SPI.

MCH/(G)MCH - Some boards use older terminology to refer to the X58 chipset, for example the Biostar TPower X58 calls it the "(G)MCH". This is outdated as "MCH" stands for "Memory Controller Hub" and the memory controller on this platform is in the CPU.

QPI VTT - This is technically a voltage name but it warrants some extra explanation. VTT stands, oddly, for Termination Voltage (Voltage To Terminate?). On past Intel platforms there was an "FSB Termination" voltage that was basically the CPU's side of the base clock. For 1366, the Uncore voltage does a similar thing - so some boards call it VTT. Not to be confused with memory VTT.

DRAM Core - Uncore voltage again. Asus decided to name this voltage after two things it isn't (memory voltage and core voltage). It makes a kind of weird sense in that it supplies the memory controller logic, but also it really doesn't make a lot of sense.

Voltages¶

Template:

Names:

• Asus:

• Asrock:

• Biostar:

• Foxconn:

• Gigabyte:

• Intel:

• MSI:

CPU Core Voltage¶

Names:

• Asus: CPU Voltage

• Asrock: CPU Voltage

• Biostar: CPU Vcore

• Foxconn: CPU Core Voltage

• Gigabyte: CPU Vcore

• Intel: CPU Voltage ("Static CPU Voltage Override")

• MSI: CPU Voltage

CPU Uncore Voltage¶

Names:

• Asus: QPI/DRAM Core Voltage

• Asrock: VTT Voltage

• Biostar: CPU VTT

• Foxconn: CPU VTT (UnCore) Voltage

• Gigabyte: QPI/Vtt Voltage

• Intel: QPI / Uncore Voltage Override

• MSI: QPI Voltage

IOH Core Voltage¶

Names:

• Asus: IOH Voltage

• Asrock: IOH Voltage

• Biostar: NB VCC

• Foxconn: X58 IOH Core Voltage

• Gigabyte: IOH Core

• Intel: IOH Core Voltage Override

• MSI: IOH Voltage

Memory Voltage¶

Names:

• Asus: DRAM BUS Voltage

• Asrock: DRAM Voltage

• Biostar: DRAM Voltage

• Foxconn: DRAM Voltage

• Gigabyte: DRAM Voltage

• Intel: Memory Voltage

• MSI: DRAM Voltage

ICH Core Voltage¶

Names:

• Asus: ICH Voltage

• Asrock: ICH Voltage

• Biostar: SB VCC

• Foxconn: ?

• Gigabyte: ICH Core

• Intel: -

• MSI: ICH Voltage

Regular OC¶

Extreme OC - 45nm¶

45nm Nehalem chips get great cold scaling but have a pretty high sweet spot. The exact location depends on the chip but it may be as high as -40C. Some chips even seem to coldbug at dry ice temps!