The bit where we'll spend most of our time
Options are little changed from X38.
Certain features - CPU GTLREF1 &2 Voltage Ratio are hidden options and you need to press [CTRL] + [F1] in the Main Menu page to enable accress.
Robust Graphics Booster - Best to use Auto or Turbo
CPU Clock Ratio - Set CPU Multiplier
For 45nm CPU's the half multiplier is also available.
CPU Host Clock Control - Options are Enabled or Disabled - Enable allows changing the
FSB, if an overclock fails this setting will be reset to Disabled.
Options are Enabled and Disabled. Select Enabled to change the
FSB and overclock your processor. In the event of a failed overclock this function will return to Disabled.
PCI Express Frequency - set up to 115Mhz gives a slight boost to performance & 3dmark. > 115Mhz can lead to issues with
Sata drives.
C.I.A. 2 - Gigabyte's automatic overclocking.
- Disabled
- Cruise
- Sports
- Racing
- Turbo
- Full Thrust
Performance Enhance If Static tREAD Value (tRD) is left on Auto The tRD - Performance level is set accordingh to the Option set here. Extreme gives the Tightest tRD , with Turbo being slacker & Standard slacker still. Has a big hit on performance.
System Memory Multiplier
Select the ratio that memory will run to the
FSB. Note: 2.0 = 1:1
DRAM Timing Selectable (SPD) - Options Auto , Manual. If Left on Auto
Bios will set timings depending on
FSB & SPD. To manually set memory timings , you guessed, use manual. If overclocking fails this option is set back to auto.
CPU Clock Skew Control - - AKA As CPU
PLL on other Motherboards
(G)MCH Clock Skew Control - AKS
NB PLL on other Motherboards
DDR3 Overvoltage Control - Stock = 1.5v increases Memory Voltage Over 1.5v by 0.05v to 1.55v in 0.05v Increments giving a Max DDR3 Voltage of 3.05v (1.5v stock +1.55v)
PCI-E Overvoltage Control - Stock = 1.5v Alows increasing the
PCI-E Voltage Maximum overvoltage 0.75v to give a maximum 2.25v increment 0.05v
FSB Overvoltage Control - AKA
VTT on other motherboards. Stock is 1.10v Overvoltage = 0.35v giving a maximum absolute voltage of 1.45v increment 0.05v
(G)MCH Overvoltage Control - Stock = 1.45v Max Overvoltage = 0.775v Giving 2.225v Maximum absolute Voltage. Increment 0.025v
GTLRef Is Particulasrly useful for fine tuning Quad overclocks. There isn't as wideer options here as with other Motherbords DFI & the Abit IX38 QuadGT have much more clockable options.
CPU GTLREF1 - Default 67% of
FSB Overvoltage Control Options are shown below giving Options of 70. 67, 64 & 61% for Die1
CPU GTLREF2 - Default 63% of
FSB Overvoltage Control Options are shown below giving Options 63, 60, 57, 54% for Die2
On the Abit board I found a GTLref of 67% Die1 & 66% Die2 gave me that extra bit. As you can see thereis little option to fine tune GTLRef very far here.
Loadline Calibration - AKA Voltage Damper. Reduces the amount of vdroop & therefore reduces the overall vcore required to overclock the CPU. Vdroop under load is around 0.05, so If a Load vcore of 1.38v is needed to get an overclock the vcore needs to be 1.38v +.05v = 1.43v. However with Loadline Calibration enabled vdroop is reduced to about 0.02v so in the above example a vcore of 1.40v will probably work.
Bad news is that using this feature does stress
PWM.
CPU Voltage Control - Range is deperndent on installed CPU (45nm CPU have a lower voltage)
Round the motherboard - (4of4)
Fasten, but don't overtighten, one of the spring screws from 2)onto the end of the bolt on the top of the mobo. Repeat for the 2nd bolt. 
Linear Mode
