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Exactly what the title says. Hopefully this will be the only stop needed to get a great OC with Gigabyte's P45 boards and Penryns. I haven't tried my E8400 yet so if you're using an E8x00 we need your input. Please chime in when you see something missing or incorrect. I appreciate all the input I can get! Help me compile as much info as we can here.
My system:
Motherboard: Gigabyte EP45-DS3R, F8 BIOS
CPU: Intel Core 2 Q9450
Memory: Mushkin Ascent PC2-8500, 2x2GB
PSU: Seasonic M12 500W
Cooling: Air, Noctua NH-U12P w/ a 2nd 120mm fan, Scythe Kaze
Case: Antec P182
Video: PNY xlr8 8800GT 721/1.8/999
OS: Vista 64 HP || XP Home
The BIOS shipped didn't work w/ my video card (F5 maybe?) but F7 and F8 have been good to me. I do NOT disable SpeedStep or any power saving features, nor do I disable VT. Sometimes I temporarily disable C1E & SpeedStep while OCing for screenshots etc.
Last update: August 17, 2008, 9:15 AM
I'll cite settings for 3 clock speeds, when the settings differ:
1) 8x 440 = 3.52 GHz, prime stable for 9d18h45m
2) 8x 490 = 3.92 GHz, prime stable overnight (~ 8-10 hours)
3) 8x 500 = 4.00 GHz, my personal best, prime stable over 1h15m but I am scared of the temps & voltage (80C, 1.42v)
All these BIOS settings are in M.I.T. - Motherboard Intelligent Tweaker.
CPU Clock Ratio:
Stock: 8x (for the Q9450)
Mine: 8x
This multiplied by your clock speed gives your final cpu clock. Range is 6-8 for the Q9450.
Clock Chip Control
>>> Standard Clock Control
CPU Host Frequency (FSB clock):
Stock: 333MHz (for the Q9450)
Mine(440): 440MHz
Mine(490): 490MHz
Mine(500): 500MHz
No explanation necessary, is there? Push her as high as you can, especially if you only have an 8x multiplier.
>>> Advanced Clock Control
CPU Clock skew:
Stock: 0ps
Mine: 150ps
This and MCH clock skew are like voodoo. The benefits are clear but the only way to find out if it helps is trial & error. I lucked out and found that 100ps CPU skew & 250ps MCH skew let me boot at FSB clock speeds I couldn't even POST at, such as 475MHz. At lower clocks they help stabilize things too. I can get higher clocks with all stock voltage. Then with some trial & error going for 500fsb I found 150 was a bit better. Make sure you read MCH skew for more info (next, just keep reading).
MCH Clock skew:
Stock: 0ps
Mine: 250ps
See CPU Clock skew above for basics. The trick to tuning these is that they go together, so you should make a grid with timings your board allows and then start trying random combos till something helps at frequencies you can't even POST at. Then when you hit something keep tuning them trying all the near combos. Tedious, but essential.
DRAM Performance Control
Performance Enhance:
Stock: Turbo
Mine: Standard
I don't know what this changes, haven't bothered testing it.
(G)MCH Frequency Latch:
Stock: Auto
Mine: 333MHz
This would be your FSB strap in Asus/AMI lingo. At low fsb speeds I can set this to 400 or 333, but at higher speeds I have to keep it at 333 and keep a 1:1 ratio (see below).
System Memory Multiplier:
Stock: Auto
Mine(440): 2.40B
Mine(450-500): 2.00B
This changes your FSB strap according to the letter suffix. To run my memory & cpu in sync I have to keep this at 2.00x, and specifically 2.00B at higher clocks. The letter suffix is explained in the BIOS.
At 5:6, 1056MHz, latch is 333MHz (2.40B).
memory clock = latch * FSB = 2.4 * 440 = 1056MHz
multiplier (or divider) = FSB / RAM = 440 / 528 = 5/6
DRAM Timing Selectable:
Stock: Auto
Mine: Manual
I have these at 5-5-5-15, I'm leaving the fine-tuning till I find my max stable speed, but <= DDR-950 I find 5-4-4-12 is stable. I also lower tRFC to 50-52.
Advanced Timing Control
I lower tRFC to 50-52.
Not yet.... There will be more here later. I only know what a few of them really do so far.
Voltage
CPU Vcore:
Stock: 1.25v
Mine(440): 1.35v
Mine(490): 1.48v
Mine(500): 1.55v
Voltage to your cpu. Defaults to ~ 1.25v for 45nm cpus. Max. recommended by Intel is 1.38v for the Q9450, and >= 1.45v you are outside spec and may damage your CPU, but they don't say whether this is idle or load! I take it to mean under load, when the current is high. My board has a vdrop of ~ 0.05 above 1.3, and ~ 0.01-0.02 below 1.25 or so. vdroop is 0.05 - 0.07. 1.55v for 500 results in 1.42v load / 1.508v idle.
I don't want to be the one to find out that 1.45v (CPU-Z reading, load) kills your CPU in 3 months. I won't run 4GHz often. 1.42 already sounds high to me, so that's my limit (for now anyway!)
1.35 BIOS results in 1.248 load and 1.312 idle.
CPU Termination:
Stock: 1.2v
Mine(440): 1.24v
Mine(490): 1.34v
Mine(500): 1.36v
This is known as CPU VTT on Asus boards. Turning this up helps at high frequencies but I found that after setting the clock skews I could turn this down to the stock setting and still get >400 mhz. The default is low for quads but the max is the same as vcore: exceed 1.45v at your own risk! Personally, I don't push it past 1.46 because of the qx9650 that was killed by anandtech. I haven't seen any benefit to pushing it past 1.34 or so. The 1.36 there was just for good measure.
CPU PLL:
Stock: 1.5v
Mine(440): 1.57v
Mine(490-500): 1.61v
When increasing vcore + other settings I increase this too. I am uncertain of what it does, and I have seen recommendations that this stay below 1.55v. This board goes in weird increments, 1.5 -> 1.57 -> 1.59 -> 1.61. Again, 1.61 is for good measure; I think 1.59 is probably enough.
CPU Reference:
Stock: 0.76v
Mine: 0.76v (auto)
I gather that reference voltages are used to determine whether a signal is high/low. At higher voltages it may be wise to increase this slightly. I believe I read that this should be 65-70% of vcore. In my experience this is best left on auto. Tweaking it up bought me a few more seconds of small ffts once. yay.
MCH Core:
Stock: 1.1v
Mine(440): 1.2v
Mine(450-500): 1.3v
Voltage to your NB (north bridge). MCH stands for Memory Controller Hub. I haven't seen any benefit rasing this past 1.3. It might be safe to break 1.4 but I haven't found any info on how much it can take, and it doesn't seem to need it. You can probably get away with 1.24 - 1.28 even at 500.
MCH reference:
Stock: 0.9v
Mine: 0.9v
The same as the other ref. voltages but for your NB.
MCH DRAM/reference:
Stock: 0.76v
Mine: 0.76v
See other reference voltages above.
ICH I/O:
Stock: 1.5v
Mine: 1.5v
Voltage for your SB (south bridge). ICH stands for I/O Controller Hub. I've seen no reason to change this.
DRAM Voltage:
Stock: 2.0-2.1v
Mine: 2.06v
Another no brainer, volts to your memory. My board give your memory a bit more than you specify here. I get 2.06-2.08.
DRAM Termination
Stock: 0.9v
Mine: 0.9v
This is the voltage that terminates signals to your memory.
Channel A/B Reference:
Stock: 0.9v
Mine: 0.9v
The same as CPU reference but for memory.
If you want me to list a BIOS setting I skipped over just let me know.
Photos & Screenshots
I'll take a couple photos of my BIOS later. My Q9450 everyday clock is 475 / 3.8GHz for the time being but that's now in my P5Q-E. My E8400 chugs along at 3.6ghz for every day use in the EP45-DS3R so I'll photograph those settings sometime.
This is 500 / 4.0GHz:
BIOS Settings Template
GIGABYTE GA-EP45-DS3R
MB Intelligent Tweaker(M.I.T.)
Robust Graphics Booster ..................: Turbo
CPU Clock Ratio ..........................: 8
Fine CPU Clock Ratio......................: 0
CPU Frequency ............................: 4,000Mhz
Clock Chip Control
Standard Clock Control
CPU Host Clock Control..................: Enabled
CPU Host Frequency (Mhz) ...............: 500Mhz
PCI Express Frequency (Mhz) ............: 100Mhz
C.I.A. 2
Advanced Clock Control [Press Enter]
CPU Clock Drive..........................: 800mv
PCI Express Clock Drive..................: 900mv
CPU Clock Skew (ps)......................: 150ps
MCH Clock Skew (ps)......................: 250ps
DRAM Performance Control
Performance Enhance....................: [Standard]
Extreme Memory Profile (X.M.P.) .......: Disabled
(G)MCH Frequency Latch.................: [333MHz]
System Memory Multiplier ..............: 2.00B
Memory Frequency (Mhz) ................: 1,000Mhz
DRAM Timing Selectable ................: Manual
Standard Timing Control
CAS Latency Time ..............................: 5
tRCD ..........................................: 5
tRP' ..........................................: 5
tRAS ..........................................: 15
Advanced Timing Control [Press Enter]
tRRD............................................: auto
tWTR............................................: auto
tWR.............................................: auto
tRFC............................................: 52
tRTP............................................: auto
Command Rate (CMD) .............................: Auto
Channel A
Static tRead Value.........................:Auto
tRD Phase0 Adjustmen......................:Auto
tRD Phase1 Adjustment......................:Auto
tRD Phase2 Adjustment ....................:Auto
tRD Phase3 Adjustment.....................:Auto
Trd2rd(Different Rank).....................:Auto
Twr2wr(Different Rank).....................:Auto
Twr2rd(Different Rank).....................:Auto
Trd2wr(Same/Diff Rank).....................:Auto
Channel B
Static tRead Value.........................:Auto
tRD Phase0 Adjustmen......................:Auto
tRD Phase1 Adjustment......................:Auto
tRD Phase2 Adjustment ....................:Auto
tRD Phase3 Adjustment.....................:Auto
Trd2rd(Different Rank).....................:Auto
Twr2wr(Different Rank).....................:Auto
Twr2rd(Different Rank).....................:Auto
Trd2wr(Same/Diff Rank).....................:Auto
Motherboard Voltage Control
Voltage Type.... Normal
CPU
CPU Vcore..........................: 1.556v (this is 1.408v after vdrop/droop)
CPU Termination..... 1.200V*.......: 1.36v
CPU PLL....1.500V*.................: 1.61v
CPU Referen.....0.755V*............: Auto
CPU Reference2,,0.800V*............: Auto
MCH/ICH
MCH Core.....1.100V.................: 1.300
MCH Reference..0.800V...............: Auto
MCH/DRAM Ref.......0.900V...........: Auto
ICH I/O.....1.500V..................: Auto
ICH Core...1.100V...................: Auto
DRAM
DRAM Voltage ....1.800V...............: 2.06v
DRAM Termination .0.900V..............: Normal
Channel A Reference 0.900V............: Normal
Channel B Reference 0.900V............: Normal
{U]Advanced Settings{U]
Limit CPUID Max. to 3.....................: Disabled
No-Execute Memory Protect.................: Enabled
CPU Enhanced Halt (C1E)...................: Enabled
CPU EIST Function.........................: Enabled
Virtualization Technology.................: Enabled
Note: * refers to 45nm CPU
My system:
Motherboard: Gigabyte EP45-DS3R, F8 BIOS
CPU: Intel Core 2 Q9450
Memory: Mushkin Ascent PC2-8500, 2x2GB
PSU: Seasonic M12 500W
Cooling: Air, Noctua NH-U12P w/ a 2nd 120mm fan, Scythe Kaze
Case: Antec P182
Video: PNY xlr8 8800GT 721/1.8/999
OS: Vista 64 HP || XP Home
The BIOS shipped didn't work w/ my video card (F5 maybe?) but F7 and F8 have been good to me. I do NOT disable SpeedStep or any power saving features, nor do I disable VT. Sometimes I temporarily disable C1E & SpeedStep while OCing for screenshots etc.
Last update: August 17, 2008, 9:15 AM
I'll cite settings for 3 clock speeds, when the settings differ:
1) 8x 440 = 3.52 GHz, prime stable for 9d18h45m
2) 8x 490 = 3.92 GHz, prime stable overnight (~ 8-10 hours)
3) 8x 500 = 4.00 GHz, my personal best, prime stable over 1h15m but I am scared of the temps & voltage (80C, 1.42v)
All these BIOS settings are in M.I.T. - Motherboard Intelligent Tweaker.
CPU Clock Ratio:
Stock: 8x (for the Q9450)
Mine: 8x
This multiplied by your clock speed gives your final cpu clock. Range is 6-8 for the Q9450.
Clock Chip Control
>>> Standard Clock Control
CPU Host Frequency (FSB clock):
Stock: 333MHz (for the Q9450)
Mine(440): 440MHz
Mine(490): 490MHz
Mine(500): 500MHz
No explanation necessary, is there? Push her as high as you can, especially if you only have an 8x multiplier.
>>> Advanced Clock Control
CPU Clock skew:
Stock: 0ps
Mine: 150ps
This and MCH clock skew are like voodoo. The benefits are clear but the only way to find out if it helps is trial & error. I lucked out and found that 100ps CPU skew & 250ps MCH skew let me boot at FSB clock speeds I couldn't even POST at, such as 475MHz. At lower clocks they help stabilize things too. I can get higher clocks with all stock voltage. Then with some trial & error going for 500fsb I found 150 was a bit better. Make sure you read MCH skew for more info (next, just keep reading).
MCH Clock skew:
Stock: 0ps
Mine: 250ps
See CPU Clock skew above for basics. The trick to tuning these is that they go together, so you should make a grid with timings your board allows and then start trying random combos till something helps at frequencies you can't even POST at. Then when you hit something keep tuning them trying all the near combos. Tedious, but essential.
DRAM Performance Control
Performance Enhance:
Stock: Turbo
Mine: Standard
I don't know what this changes, haven't bothered testing it.
(G)MCH Frequency Latch:
Stock: Auto
Mine: 333MHz
This would be your FSB strap in Asus/AMI lingo. At low fsb speeds I can set this to 400 or 333, but at higher speeds I have to keep it at 333 and keep a 1:1 ratio (see below).
System Memory Multiplier:
Stock: Auto
Mine(440): 2.40B
Mine(450-500): 2.00B
This changes your FSB strap according to the letter suffix. To run my memory & cpu in sync I have to keep this at 2.00x, and specifically 2.00B at higher clocks. The letter suffix is explained in the BIOS.
At 5:6, 1056MHz, latch is 333MHz (2.40B).
memory clock = latch * FSB = 2.4 * 440 = 1056MHz
multiplier (or divider) = FSB / RAM = 440 / 528 = 5/6
DRAM Timing Selectable:
Stock: Auto
Mine: Manual
I have these at 5-5-5-15, I'm leaving the fine-tuning till I find my max stable speed, but <= DDR-950 I find 5-4-4-12 is stable. I also lower tRFC to 50-52.
Advanced Timing Control
I lower tRFC to 50-52.
Not yet.... There will be more here later. I only know what a few of them really do so far.
Voltage
CPU Vcore:
Stock: 1.25v
Mine(440): 1.35v
Mine(490): 1.48v
Mine(500): 1.55v
Voltage to your cpu. Defaults to ~ 1.25v for 45nm cpus. Max. recommended by Intel is 1.38v for the Q9450, and >= 1.45v you are outside spec and may damage your CPU, but they don't say whether this is idle or load! I take it to mean under load, when the current is high. My board has a vdrop of ~ 0.05 above 1.3, and ~ 0.01-0.02 below 1.25 or so. vdroop is 0.05 - 0.07. 1.55v for 500 results in 1.42v load / 1.508v idle.
I don't want to be the one to find out that 1.45v (CPU-Z reading, load) kills your CPU in 3 months. I won't run 4GHz often. 1.42 already sounds high to me, so that's my limit (for now anyway!
) 1.35 BIOS results in 1.248 load and 1.312 idle.
CPU Termination:
Stock: 1.2v
Mine(440): 1.24v
Mine(490): 1.34v
Mine(500): 1.36v
This is known as CPU VTT on Asus boards. Turning this up helps at high frequencies but I found that after setting the clock skews I could turn this down to the stock setting and still get >400 mhz. The default is low for quads but the max is the same as vcore: exceed 1.45v at your own risk! Personally, I don't push it past 1.46 because of the qx9650 that was killed by anandtech. I haven't seen any benefit to pushing it past 1.34 or so. The 1.36 there was just for good measure.
CPU PLL:
Stock: 1.5v
Mine(440): 1.57v
Mine(490-500): 1.61v
When increasing vcore + other settings I increase this too. I am uncertain of what it does, and I have seen recommendations that this stay below 1.55v. This board goes in weird increments, 1.5 -> 1.57 -> 1.59 -> 1.61. Again, 1.61 is for good measure; I think 1.59 is probably enough.
CPU Reference:
Stock: 0.76v
Mine: 0.76v (auto)
I gather that reference voltages are used to determine whether a signal is high/low. At higher voltages it may be wise to increase this slightly. I believe I read that this should be 65-70% of vcore. In my experience this is best left on auto. Tweaking it up bought me a few more seconds of small ffts once. yay.
MCH Core:
Stock: 1.1v
Mine(440): 1.2v
Mine(450-500): 1.3v
Voltage to your NB (north bridge). MCH stands for Memory Controller Hub. I haven't seen any benefit rasing this past 1.3. It might be safe to break 1.4 but I haven't found any info on how much it can take, and it doesn't seem to need it. You can probably get away with 1.24 - 1.28 even at 500.
MCH reference:
Stock: 0.9v
Mine: 0.9v
The same as the other ref. voltages but for your NB.
MCH DRAM/reference:
Stock: 0.76v
Mine: 0.76v
See other reference voltages above.
ICH I/O:
Stock: 1.5v
Mine: 1.5v
Voltage for your SB (south bridge). ICH stands for I/O Controller Hub. I've seen no reason to change this.
DRAM Voltage:
Stock: 2.0-2.1v
Mine: 2.06v
Another no brainer, volts to your memory. My board give your memory a bit more than you specify here. I get 2.06-2.08.
DRAM Termination
Stock: 0.9v
Mine: 0.9v
This is the voltage that terminates signals to your memory.
Channel A/B Reference:
Stock: 0.9v
Mine: 0.9v
The same as CPU reference but for memory.
If you want me to list a BIOS setting I skipped over just let me know.
Photos & Screenshots
I'll take a couple photos of my BIOS later. My Q9450 everyday clock is 475 / 3.8GHz for the time being but that's now in my P5Q-E. My E8400 chugs along at 3.6ghz for every day use in the EP45-DS3R so I'll photograph those settings sometime.
This is 500 / 4.0GHz:
BIOS Settings Template
GIGABYTE GA-EP45-DS3R
MB Intelligent Tweaker(M.I.T.)
Robust Graphics Booster ..................: Turbo
CPU Clock Ratio ..........................: 8
Fine CPU Clock Ratio......................: 0
CPU Frequency ............................: 4,000Mhz
Clock Chip Control
Standard Clock Control
CPU Host Clock Control..................: Enabled
CPU Host Frequency (Mhz) ...............: 500Mhz
PCI Express Frequency (Mhz) ............: 100Mhz
C.I.A. 2
Advanced Clock Control [Press Enter]
CPU Clock Drive..........................: 800mv
PCI Express Clock Drive..................: 900mv
CPU Clock Skew (ps)......................: 150ps
MCH Clock Skew (ps)......................: 250ps
DRAM Performance Control
Performance Enhance....................: [Standard]
Extreme Memory Profile (X.M.P.) .......: Disabled
(G)MCH Frequency Latch.................: [333MHz]
System Memory Multiplier ..............: 2.00B
Memory Frequency (Mhz) ................: 1,000Mhz
DRAM Timing Selectable ................: Manual
Standard Timing Control
CAS Latency Time ..............................: 5
tRCD ..........................................: 5
tRP' ..........................................: 5
tRAS ..........................................: 15
Advanced Timing Control [Press Enter]
tRRD............................................: auto
tWTR............................................: auto
tWR.............................................: auto
tRFC............................................: 52
tRTP............................................: auto
Command Rate (CMD) .............................: Auto
Channel A
Static tRead Value.........................:Auto
tRD Phase0 Adjustmen......................:Auto
tRD Phase1 Adjustment......................:Auto
tRD Phase2 Adjustment ....................:Auto
tRD Phase3 Adjustment.....................:Auto
Trd2rd(Different Rank).....................:Auto
Twr2wr(Different Rank).....................:Auto
Twr2rd(Different Rank).....................:Auto
Trd2wr(Same/Diff Rank).....................:Auto
Channel B
Static tRead Value.........................:Auto
tRD Phase0 Adjustmen......................:Auto
tRD Phase1 Adjustment......................:Auto
tRD Phase2 Adjustment ....................:Auto
tRD Phase3 Adjustment.....................:Auto
Trd2rd(Different Rank).....................:Auto
Twr2wr(Different Rank).....................:Auto
Twr2rd(Different Rank).....................:Auto
Trd2wr(Same/Diff Rank).....................:Auto
Motherboard Voltage Control
Voltage Type.... Normal
CPU
CPU Vcore..........................: 1.556v (this is 1.408v after vdrop/droop)
CPU Termination..... 1.200V*.......: 1.36v
CPU PLL....1.500V*.................: 1.61v
CPU Referen.....0.755V*............: Auto
CPU Reference2,,0.800V*............: Auto
MCH/ICH
MCH Core.....1.100V.................: 1.300
MCH Reference..0.800V...............: Auto
MCH/DRAM Ref.......0.900V...........: Auto
ICH I/O.....1.500V..................: Auto
ICH Core...1.100V...................: Auto
DRAM
DRAM Voltage ....1.800V...............: 2.06v
DRAM Termination .0.900V..............: Normal
Channel A Reference 0.900V............: Normal
Channel B Reference 0.900V............: Normal
{U]Advanced Settings{U]
Limit CPUID Max. to 3.....................: Disabled
No-Execute Memory Protect.................: Enabled
CPU Enhanced Halt (C1E)...................: Enabled
CPU EIST Function.........................: Enabled
Virtualization Technology.................: Enabled
Note: * refers to 45nm CPU