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Asus P8Z77-V: Why has my CPU BUS speed increased?

post #1 of 4
Thread Starter 
Hi, I have a question about CPU bus speed in relation to DRAM frequency. I got hold of a pair of Corsair 4GB 1866Mhz modules alongside my i5 3570K. Initially, the ASUS BIOS reported the DRAM running at 1333Mhz, so I simply changed the DRAM frequency 1866Mhz and rebooted.

After going into BIOS, I noticed the CPU core clock speed increased marginally, and tends to hover at a larger 3411- 3436Mhz after it is rebooted. CPU-Z also reports the BUS speed at approximately 105Mhz, and the DRAM frequency at around 1876Mhz.

Why does this occur, and should I stick with these settings? The ASUS BIOS has a "CPU bus speed : DRAM speed ratio" setting, which is currently set to AUTO, could that have something to do with it? I'm afraid my knowledge of this is pretty poor.

Thanks smile.gif
Edited by afx1991 - 3/24/13 at 2:28pm
post #2 of 4
Run Prime95 for 30mins, if it is stable then I woudlnt worry about it. It happens on some motherboards etc, you cant really complain if you got another 30MHz for free tongue.gif

I guess if you tinker with it you could get it easily, but since the number isnt as even as 1600 and 2400, it may need a slightly bigger number to achieve it
     
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CPUMotherboardGraphicsRAM
Intel Core i7 3820 @ 4.5Ghz ASUS Rampage IV Formula X79 EVGA GTX 980 Ti Hybrid @ 1450/1900 Corsair Dominator 16gb @ 2.2GHz C9 
Hard DriveHard DriveHard DriveCooling
WD Caviar Blue 1tb 7200RPM WD Caviar Blue 1tb 7200RPM WD Caviar Blue 500gb 7200RPM 120.5 Custom Loop 
OSMonitorKeyboardPower
Windows 10 Pro x64 LG D2343P-BN 3D Monitor @ 70Hz Corsair K70 (MX Brown) Corsair AX Series 850w 
CaseMouseAudio
NZXT Switch 810 Black (Heavily Modded) Logitech G502 Proteus Spectrum Sennheiser HD 598 Cs 
CPUMotherboardGraphicsRAM
AMD FX-6300 @ 4.5Ghz Gigabyte 970A UD3 AMD HD8490 (OEM) @ 1.1Ghz Core/Mem Patriot Viper Xtreme 8gb @1600MHz 8-8-8-24 
Optical DriveCoolingCoolingOS
LiteOn Bluray Player Corsair Hydro Series H100i Zalman 120mm Led Fans x4 Windows 10 Pro x64 
MonitorKeyboardPowerCase
Hitachi 24" 70Hz Monitor Logitech EX110 OCZ ZT 550w Full Modular Zalman Z9 Plus 
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DELL Wireless Mouse Logitech 5.1 Sound System TP-Link TL-WN781ND Wireless Card 
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post #3 of 4
Thread Starter 
Alright thanks, I might just try that then. Any particular Prime95 settings I should use? And it passes if there's no errors generated?

EDIT: I reset the BIOS settings and simply enabled XMP in the tweaker menu, and the 1866MHz speed along with its correct timings etc were detected by default.

The CPU bus speed is now as expected (100MHz) and so is the DRAM's (933.4*2) Although the BIOS reports the clock speed as 3411Mhz. Again, I have no idea how this comes about! tongue.gif
Edited by afx1991 - 3/24/13 at 2:58pm
post #4 of 4
30MHz is nothing, there is actually no point of running it, but for future reference, set it to blend and do it overnight when finding a stable OC
     
CPUMotherboardGraphicsRAM
Intel Core i7 3820 @ 4.5Ghz ASUS Rampage IV Formula X79 EVGA GTX 980 Ti Hybrid @ 1450/1900 Corsair Dominator 16gb @ 2.2GHz C9 
Hard DriveHard DriveHard DriveCooling
WD Caviar Blue 1tb 7200RPM WD Caviar Blue 1tb 7200RPM WD Caviar Blue 500gb 7200RPM 120.5 Custom Loop 
OSMonitorKeyboardPower
Windows 10 Pro x64 LG D2343P-BN 3D Monitor @ 70Hz Corsair K70 (MX Brown) Corsair AX Series 850w 
CaseMouseAudio
NZXT Switch 810 Black (Heavily Modded) Logitech G502 Proteus Spectrum Sennheiser HD 598 Cs 
CPUMotherboardGraphicsRAM
AMD FX-6300 @ 4.5Ghz Gigabyte 970A UD3 AMD HD8490 (OEM) @ 1.1Ghz Core/Mem Patriot Viper Xtreme 8gb @1600MHz 8-8-8-24 
Optical DriveCoolingCoolingOS
LiteOn Bluray Player Corsair Hydro Series H100i Zalman 120mm Led Fans x4 Windows 10 Pro x64 
MonitorKeyboardPowerCase
Hitachi 24" 70Hz Monitor Logitech EX110 OCZ ZT 550w Full Modular Zalman Z9 Plus 
MouseAudioOther
DELL Wireless Mouse Logitech 5.1 Sound System TP-Link TL-WN781ND Wireless Card 
  hide details  
Reply
     
CPUMotherboardGraphicsRAM
Intel Core i7 3820 @ 4.5Ghz ASUS Rampage IV Formula X79 EVGA GTX 980 Ti Hybrid @ 1450/1900 Corsair Dominator 16gb @ 2.2GHz C9 
Hard DriveHard DriveHard DriveCooling
WD Caviar Blue 1tb 7200RPM WD Caviar Blue 1tb 7200RPM WD Caviar Blue 500gb 7200RPM 120.5 Custom Loop 
OSMonitorKeyboardPower
Windows 10 Pro x64 LG D2343P-BN 3D Monitor @ 70Hz Corsair K70 (MX Brown) Corsair AX Series 850w 
CaseMouseAudio
NZXT Switch 810 Black (Heavily Modded) Logitech G502 Proteus Spectrum Sennheiser HD 598 Cs 
CPUMotherboardGraphicsRAM
AMD FX-6300 @ 4.5Ghz Gigabyte 970A UD3 AMD HD8490 (OEM) @ 1.1Ghz Core/Mem Patriot Viper Xtreme 8gb @1600MHz 8-8-8-24 
Optical DriveCoolingCoolingOS
LiteOn Bluray Player Corsair Hydro Series H100i Zalman 120mm Led Fans x4 Windows 10 Pro x64 
MonitorKeyboardPowerCase
Hitachi 24" 70Hz Monitor Logitech EX110 OCZ ZT 550w Full Modular Zalman Z9 Plus 
MouseAudioOther
DELL Wireless Mouse Logitech 5.1 Sound System TP-Link TL-WN781ND Wireless Card 
  hide details  
Reply
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