Volt mods

When overclocking increasing the voltage can usually benefit the maximum overclockability, as long as you have the cooling to make up for it. Almost every component has voltage modifications. Some will provide a very healthy voltage boost, some mods are used to stabilize voltage, and some provide little to nothing.

How a Volt mod works

Most components use a circuit that automatically detects and corrects the voltage constantly. When the voltage drops, the chip tells the system to give it more, and vice versa for too much voltage.
A volt mod, however, is intended to correct problems, and/or surpass those options that are available in the bios though they do have their limitations.

Volt mods work, by creating resistance on the voltage sensing line, to act as if the components aren’t receiving enough voltage- this in turn will allow you to physically bypass what’s available in the bios, and select everything manually.

Most mods require modifying the motherboard.

Motherboard voltage mods

Although most mods are performed on the motherboard and affect the removable components, there are mods to alter the voltages of the non-removable components of the motherboard.

• VDD- Chipset voltage. For PC's using a Northbridge, this mod is usually useful for obtaining higher FSB speeds.
• Vagp- AGP voltage. This mod changes the voltage of the communication link between the North Bridge and AGP card itself- it does NOT effect video card voltage levels (i.e. GPU).
• Vfsb (?)
• Cap mods - Cap mods are usually considered some of, if not the most extreme mods, of all mods. Cap mods are adding capacitors inline with the circuits to provide either cleaner power, or to provide a more stable voltage under load. Caps have been added to motherboards, video cards, and even ram. However, cap mods do not return as significant of results as volt mods and improved cooling, but can help obtain that extra 3-10mhz when pushing the components excessively.

Video card voltage modifications

Voltage modifying a video card can be fun, rewarding, risky, and extremely costly! Do it correctly, and it could net you a very nice overclock, but mess it up, and if you're modding a brand new $700 video card, you could easily kill it and render it a $700 doorstop.

• VGPU- GPU core voltage. Increase this to do the same as a Vcore increase with a CPU. Keep in mind, some GPU's may be more sensitive to voltage to others, and too much voltage WILL kill a GPU.
• VDDQ- This is the voltage for the input/output of the memory. Basically the voltage for the bus between the GPU and memory itself. (DQ bus voltage)
• Vddr- the main DDR voltage for your video cards ram.
• Vref-(Reference voltage)- The reference voltage for VDDQ calculated by .7*VDDQ.

CPU Voltage modifications

The primary (and currently, only) voltage modification available for the CPU is the Vcore. Older CPU's had off-die cache, which was powered separately, and could be modified. Too much voltage in a CPU will easily kill it. Some CPU designs are very voltage tolerant, and react well, and can take loads (Athlon XP’s), and others (Pentium IV’s) don't.

Ram voltage modifications

• Vdimm - The primary DDR voltage- most effective at increasing an overclock.
• VTT -( Reference voltage) the VTT is supposed to always be 1/2 of the Vdimm, and is used to keep track of the Vdimm. If the VTT drops from 1.6 to 1.5, your Vdimm will follow from 3.2v to 3v. VTT drooping is very, very bad.
• Memtest 86 - While not a mod, Memtest 86 is the most vital tool used in overclocking memory to maintain stability, however, ram passing memtest only proves that the ram itself is maintaining consistency when reading and writing to the IC's. Memtest stability does NOT mean your memory controller is capable of handling the excess load created by the increased power draw, and speeds.
• Hipro's ram mod - First and only physical cap mod I've located for ram, success, however, is undocumented at this time.