Overclock.net › Forums › Intel › Intel CPUs › CPU VTT on E8400
New Posts  All Forums:Forum Nav:

CPU VTT on E8400

post #1 of 9
Thread Starter 
I've searched the threads but can't seem to find any definitive answer. Anyone able to tell me what the correct CPU VTT is for the E8400? I've noticed that my OC appears to be unstable with it set to 1.2v yet rock solid stable at 1.3v. Is this too high for the Wolfdale?
Desktop
(13 items)
 
  
CPUMotherboardGraphicsRAM
i7-2600k @ 4.6Ghz 24/7 Asrock Fatal1ty Pro Gen3 POV 570 GTX 2.5GB, Inno3D 8800GT 16GB Gskill Ripjaw X 
Hard DriveOptical DriveOSMonitor
Crucial M4 512GB, 4xWDRE4 1TB RAID10 OCZ60GB Cache LG BH10 Bluray Writer Win7 x64 GPT Dell U2711 + Samsung 2232BW 
KeyboardPowerCaseMouse
Corsair Vengeance K90 Corsair TX950W Fractal Design Define XL Cyborg R.A.T 7 
  hide details  
Reply
Desktop
(13 items)
 
  
CPUMotherboardGraphicsRAM
i7-2600k @ 4.6Ghz 24/7 Asrock Fatal1ty Pro Gen3 POV 570 GTX 2.5GB, Inno3D 8800GT 16GB Gskill Ripjaw X 
Hard DriveOptical DriveOSMonitor
Crucial M4 512GB, 4xWDRE4 1TB RAID10 OCZ60GB Cache LG BH10 Bluray Writer Win7 x64 GPT Dell U2711 + Samsung 2232BW 
KeyboardPowerCaseMouse
Corsair Vengeance K90 Corsair TX950W Fractal Design Define XL Cyborg R.A.T 7 
  hide details  
Reply
post #2 of 9
Not the CPU VTT you need to worry about. That can go as high as 1.5V on that. The voltage you need to mess with is the CPU overvolt or something like that, I think it's the first one on the voltage control page.

If you could, go ahead and fill out your System Specs in the User CP, and download CPU-Z and show us a screenshot of it.

-edit-

Rebooted to check the BIOS. At least on my DFI, it's labeled as CPU Special Vid Add. I set the to around 150 and then start OCing. Remember to keep monitoring voltages in CPU-Z (try to keep it under 1.3625V if at all possible, that voltage and up has been known to kill chips, and no, the CPU VTT at 1.5V won't kill the CPU) and monitor temps with either Speedfan or Coretemp.
    
CPUMotherboardGraphicsRAM
i7 4790k @ 4.7GHz Asus Z97 Pro Gaming EVGA 1080 Ti FTW3 @ 2050 MHz 32GB G Skill Sniper DDR3-2133 
Hard DriveHard DriveHard DriveOptical Drive
Intel 600p m.2 512GB Crucial M500 SSD 960GB Toshiba X300 HDD 3TB LG Blu Ray Burner 
CoolingOSMonitorMonitor
Cooler Master Nepton 240m Windows 10 Pro Samsung 34" Curved Ultrawide (3440x1440) Samsung 22" Portrait (1080x1920) 
KeyboardPowerCaseMouse
Poker II Cherry MX Brown, KBParadise V80 Cherry... EVGA G2 650W Cooler Master Silencio 652s Steelseries Sensei Wireless 
Mouse PadAudioAudio
Tekmat SIG 556 SMSL Q5 Pro DAC Bowers & Wilkins DM601 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
i7 4790k @ 4.7GHz Asus Z97 Pro Gaming EVGA 1080 Ti FTW3 @ 2050 MHz 32GB G Skill Sniper DDR3-2133 
Hard DriveHard DriveHard DriveOptical Drive
Intel 600p m.2 512GB Crucial M500 SSD 960GB Toshiba X300 HDD 3TB LG Blu Ray Burner 
CoolingOSMonitorMonitor
Cooler Master Nepton 240m Windows 10 Pro Samsung 34" Curved Ultrawide (3440x1440) Samsung 22" Portrait (1080x1920) 
KeyboardPowerCaseMouse
Poker II Cherry MX Brown, KBParadise V80 Cherry... EVGA G2 650W Cooler Master Silencio 652s Steelseries Sensei Wireless 
Mouse PadAudioAudio
Tekmat SIG 556 SMSL Q5 Pro DAC Bowers & Wilkins DM601 
  hide details  
Reply
post #3 of 9
Thread Starter 
I know that I need to fiddle with vcore .

My other voltage settings are not really the issue here as my OC is completely stable at relatively low voltages. My question is related purely to CPU VTT. There is a pull-up device on the output buffer of the GTL circuit which reduces ringback and overshoot. Theoretically, CPU VTT should be lower than vcore otherwise the pull-up device is removed from the circuit and fails to function properly. In my case, vcore is 1.2320v, which is lower than my VTT. It also seems high for the Wolfdale, hence my question...
Desktop
(13 items)
 
  
CPUMotherboardGraphicsRAM
i7-2600k @ 4.6Ghz 24/7 Asrock Fatal1ty Pro Gen3 POV 570 GTX 2.5GB, Inno3D 8800GT 16GB Gskill Ripjaw X 
Hard DriveOptical DriveOSMonitor
Crucial M4 512GB, 4xWDRE4 1TB RAID10 OCZ60GB Cache LG BH10 Bluray Writer Win7 x64 GPT Dell U2711 + Samsung 2232BW 
KeyboardPowerCaseMouse
Corsair Vengeance K90 Corsair TX950W Fractal Design Define XL Cyborg R.A.T 7 
  hide details  
Reply
Desktop
(13 items)
 
  
CPUMotherboardGraphicsRAM
i7-2600k @ 4.6Ghz 24/7 Asrock Fatal1ty Pro Gen3 POV 570 GTX 2.5GB, Inno3D 8800GT 16GB Gskill Ripjaw X 
Hard DriveOptical DriveOSMonitor
Crucial M4 512GB, 4xWDRE4 1TB RAID10 OCZ60GB Cache LG BH10 Bluray Writer Win7 x64 GPT Dell U2711 + Samsung 2232BW 
KeyboardPowerCaseMouse
Corsair Vengeance K90 Corsair TX950W Fractal Design Define XL Cyborg R.A.T 7 
  hide details  
Reply
post #4 of 9
Quote:
Originally Posted by complexlogic View Post
I've searched the threads but can't seem to find any definitive answer. Anyone able to tell me what the correct CPU VTT is for the E8400? I've noticed that my OC appears to be unstable with it set to 1.2v yet rock solid stable at 1.3v. Is this too high for the Wolfdale?
no 1.3 is not to high. you can go to 1.36 for 24/7 and 1.45 is the absolute max unless you want to bench then you can go to 1.5 BUT STAY AWAY FROM 1.45 AND ABOVE.
Lurking Ninja
(13 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i7 920 D0 3849B203 4.0GHz/1.164 Evga X58 Classified E759/Koolance X58/BIX 120 TRI SLI GTX 285s.** 6GB 3x2 OCZ Gold 1600mhz 
Hard DriveOptical DriveOSMonitor
2x WD3200AAKS (RAID0), 1tb AALS Samsumg Wrigtmaster Sb 204/182 Windows 7 Ultimate X64 Gateway HD2401 24" 
KeyboardPowerCaseMouse
Logitech G15 V1 Corsair HX1000W Modded Rocketfish Logitech MX Revolution 
Mouse Pad
soft cotton? 
  hide details  
Reply
Lurking Ninja
(13 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i7 920 D0 3849B203 4.0GHz/1.164 Evga X58 Classified E759/Koolance X58/BIX 120 TRI SLI GTX 285s.** 6GB 3x2 OCZ Gold 1600mhz 
Hard DriveOptical DriveOSMonitor
2x WD3200AAKS (RAID0), 1tb AALS Samsumg Wrigtmaster Sb 204/182 Windows 7 Ultimate X64 Gateway HD2401 24" 
KeyboardPowerCaseMouse
Logitech G15 V1 Corsair HX1000W Modded Rocketfish Logitech MX Revolution 
Mouse Pad
soft cotton? 
  hide details  
Reply
post #5 of 9
vcore around 1.35ish is as high as I would go
vtt leave it at default, that's what everyone does. the fact that you can even set vtt is unusual, and i wouldn't want to fiddle with it unless you are an intel engineer who knows excactly what's going on inside the chip, but in that case you wouldn't need to ask on ocn would you
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
C2D E8400 @4.158GHz 1.33V Gigabyte P35-DS3R G92 8800GTS 512MB @ core 810/2000, mem 1100 Crucial Ballistix DDR2 PC6400 
Hard DriveOSMonitorKeyboard
Maxator DiamondMax 320GB 16mb Windows Vista Business (Free) LG L226WTQ 22" 2ms Logitech "Cordless" 
PowerCaseMouse
Roswell 600W Antec 900 Logitech Click! 
  hide details  
Reply
My System
(13 items)
 
  
CPUMotherboardGraphicsRAM
C2D E8400 @4.158GHz 1.33V Gigabyte P35-DS3R G92 8800GTS 512MB @ core 810/2000, mem 1100 Crucial Ballistix DDR2 PC6400 
Hard DriveOSMonitorKeyboard
Maxator DiamondMax 320GB 16mb Windows Vista Business (Free) LG L226WTQ 22" 2ms Logitech "Cordless" 
PowerCaseMouse
Roswell 600W Antec 900 Logitech Click! 
  hide details  
Reply
post #6 of 9
I was told to set VTT to 1.5V to increase stability... Thoughts?
    
CPUMotherboardGraphicsRAM
i7 4790k @ 4.7GHz Asus Z97 Pro Gaming EVGA 1080 Ti FTW3 @ 2050 MHz 32GB G Skill Sniper DDR3-2133 
Hard DriveHard DriveHard DriveOptical Drive
Intel 600p m.2 512GB Crucial M500 SSD 960GB Toshiba X300 HDD 3TB LG Blu Ray Burner 
CoolingOSMonitorMonitor
Cooler Master Nepton 240m Windows 10 Pro Samsung 34" Curved Ultrawide (3440x1440) Samsung 22" Portrait (1080x1920) 
KeyboardPowerCaseMouse
Poker II Cherry MX Brown, KBParadise V80 Cherry... EVGA G2 650W Cooler Master Silencio 652s Steelseries Sensei Wireless 
Mouse PadAudioAudio
Tekmat SIG 556 SMSL Q5 Pro DAC Bowers & Wilkins DM601 
  hide details  
Reply
    
CPUMotherboardGraphicsRAM
i7 4790k @ 4.7GHz Asus Z97 Pro Gaming EVGA 1080 Ti FTW3 @ 2050 MHz 32GB G Skill Sniper DDR3-2133 
Hard DriveHard DriveHard DriveOptical Drive
Intel 600p m.2 512GB Crucial M500 SSD 960GB Toshiba X300 HDD 3TB LG Blu Ray Burner 
CoolingOSMonitorMonitor
Cooler Master Nepton 240m Windows 10 Pro Samsung 34" Curved Ultrawide (3440x1440) Samsung 22" Portrait (1080x1920) 
KeyboardPowerCaseMouse
Poker II Cherry MX Brown, KBParadise V80 Cherry... EVGA G2 650W Cooler Master Silencio 652s Steelseries Sensei Wireless 
Mouse PadAudioAudio
Tekmat SIG 556 SMSL Q5 Pro DAC Bowers & Wilkins DM601 
  hide details  
Reply
post #7 of 9
Quote:
Originally Posted by complexlogic View Post
I've searched the threads but can't seem to find any definitive answer. Anyone able to tell me what the correct CPU VTT is for the E8400? I've noticed that my OC appears to be unstable with it set to 1.2v yet rock solid stable at 1.3v. Is this too high for the Wolfdale?
Quote:
Originally Posted by pow3rtr1p View Post
I was told to set VTT to 1.5V to increase stability... Thoughts?
To the OP with the P5N32-E. This snip is from Robilar's guide on that motherboard. It is common practice with this board to max the CPUVTT, based on his advice. No one yet has reported a problem with it set to 1.55v. I personally have it at 1.55v and have had it set that way for about a year now. I have read from the EVGA 680 threads though, that a setting about .5v less than the NB voltage is recommended, but on that board it is listed as FSBVTT.

Quote:
Originally Posted by Robilar View Post
...CPU VTT is the most important setting for stable overclocks. The CPU VTT Voltage sets the CPU termination voltage, allowing for a 1.55V maximum. Using this voltage in combination with the CPU VCore voltage setting can greatly enhance the system stability while overclocked. The system memory reference voltage is split between settings, the controller reference voltage and one option each for the two memory channels. In all cases, the base reference voltage can be set to a maximum of .03V over half of the set memory voltage. (Taken from HardOCP)
"In summary, the CPU VTT controls the CPU termination voltage. Based on Kirmie's observations, it reduces the number of false electrical signals by providing a form of "ground" to pull out these false currents. ." (Credit to Kirmie for the find) My experience with this board is that the max setting (1.55) provides the best results. I have not had a single crash or temperature variation as a result...
Quote:
Originally Posted by t4ct1c47 View Post
... VTT relates to the FSB termination voltage, which is the actual voltage that flows through the main data bus of the entire motherboard...
Lola
(17 items)
 
Charlestown
(10 items)
 
 
CPUMotherboardGraphicsRAM
2500K ASRock Z68 Extreme7 EVGA GTX 760 2x4GB Mushkin 996998 
Hard DriveHard DriveHard DriveOptical Drive
Samsung 830 256GB 2x WD RE3 RAID0 Seagate 3TB Backup 2x Samsung 223B 
CoolingOSMonitorKeyboard
Corsair H80 Win7 64Bit Samsung 226CW Razer Lycosa 
PowerCaseMouseMouse Pad
Seasonic X-650 Antec 1200 Logitech G500 Razer eXactMat 
Audio
Auzentech Prelude 
  hide details  
Reply
Lola
(17 items)
 
Charlestown
(10 items)
 
 
CPUMotherboardGraphicsRAM
2500K ASRock Z68 Extreme7 EVGA GTX 760 2x4GB Mushkin 996998 
Hard DriveHard DriveHard DriveOptical Drive
Samsung 830 256GB 2x WD RE3 RAID0 Seagate 3TB Backup 2x Samsung 223B 
CoolingOSMonitorKeyboard
Corsair H80 Win7 64Bit Samsung 226CW Razer Lycosa 
PowerCaseMouseMouse Pad
Seasonic X-650 Antec 1200 Logitech G500 Razer eXactMat 
Audio
Auzentech Prelude 
  hide details  
Reply
post #8 of 9
Thread Starter 
Accordingly to my admittedly imperfect understanding, CPU VTT and FSB VTT are different animals: the former is the termination voltage on the CPU end, and the latter is the termination voltage on the northbridge end. Setting .5v less than the NB voltage would make sense for FSB VTT, but less so for CPU VTT. I'm sure that higher voltages for CPU VTT would work as well as lower given that both are stable. I suspect, however, that higher does not equal better though...
Desktop
(13 items)
 
  
CPUMotherboardGraphicsRAM
i7-2600k @ 4.6Ghz 24/7 Asrock Fatal1ty Pro Gen3 POV 570 GTX 2.5GB, Inno3D 8800GT 16GB Gskill Ripjaw X 
Hard DriveOptical DriveOSMonitor
Crucial M4 512GB, 4xWDRE4 1TB RAID10 OCZ60GB Cache LG BH10 Bluray Writer Win7 x64 GPT Dell U2711 + Samsung 2232BW 
KeyboardPowerCaseMouse
Corsair Vengeance K90 Corsair TX950W Fractal Design Define XL Cyborg R.A.T 7 
  hide details  
Reply
Desktop
(13 items)
 
  
CPUMotherboardGraphicsRAM
i7-2600k @ 4.6Ghz 24/7 Asrock Fatal1ty Pro Gen3 POV 570 GTX 2.5GB, Inno3D 8800GT 16GB Gskill Ripjaw X 
Hard DriveOptical DriveOSMonitor
Crucial M4 512GB, 4xWDRE4 1TB RAID10 OCZ60GB Cache LG BH10 Bluray Writer Win7 x64 GPT Dell U2711 + Samsung 2232BW 
KeyboardPowerCaseMouse
Corsair Vengeance K90 Corsair TX950W Fractal Design Define XL Cyborg R.A.T 7 
  hide details  
Reply
post #9 of 9
Quote:
Originally Posted by complexlogic View Post
Accordingly to my admittedly imperfect understanding, CPU VTT and FSB VTT are different animals: the former is the termination voltage on the CPU end, and the latter is the termination voltage on the northbridge end. Setting .5v less than the NB voltage would make sense for FSB VTT, but less so for CPU VTT. I'm sure that higher voltages for CPU VTT would work as well as lower given that both are stable. I suspect, however, that higher does not equal better though...
From what I understand, and what I have learned from ericeod, you are correct. I did mention that in my post, but it was only regarding the EVGA 680 because I believe they have a slightly different BIOS setting than on the ASUS board.

I only mentioned it for others reading the thread so they dont get confused on my recommendation for maxing the CPUVTT on the ASUS board as it might not be an option, or recommended, for other boards..
Lola
(17 items)
 
Charlestown
(10 items)
 
 
CPUMotherboardGraphicsRAM
2500K ASRock Z68 Extreme7 EVGA GTX 760 2x4GB Mushkin 996998 
Hard DriveHard DriveHard DriveOptical Drive
Samsung 830 256GB 2x WD RE3 RAID0 Seagate 3TB Backup 2x Samsung 223B 
CoolingOSMonitorKeyboard
Corsair H80 Win7 64Bit Samsung 226CW Razer Lycosa 
PowerCaseMouseMouse Pad
Seasonic X-650 Antec 1200 Logitech G500 Razer eXactMat 
Audio
Auzentech Prelude 
  hide details  
Reply
Lola
(17 items)
 
Charlestown
(10 items)
 
 
CPUMotherboardGraphicsRAM
2500K ASRock Z68 Extreme7 EVGA GTX 760 2x4GB Mushkin 996998 
Hard DriveHard DriveHard DriveOptical Drive
Samsung 830 256GB 2x WD RE3 RAID0 Seagate 3TB Backup 2x Samsung 223B 
CoolingOSMonitorKeyboard
Corsair H80 Win7 64Bit Samsung 226CW Razer Lycosa 
PowerCaseMouseMouse Pad
Seasonic X-650 Antec 1200 Logitech G500 Razer eXactMat 
Audio
Auzentech Prelude 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Intel CPUs
Overclock.net › Forums › Intel › Intel CPUs › CPU VTT on E8400