nb voltage on lanparty LT x48

[ricgordon]

I am new to overclocking and this board and am trying to set up overclocking with an e8400 chip. I have gleaned there are a few basic parameters to change for beginners

1. fsb
2. cpu voltage
3. nb voltage
4. ram timings
5. ram voltage

I am confused about the northbridge voltage required on the X48 when overclocking at 400 fsb. It is rated to run a fsb up to 1600 and therefore if you are running the fsb at 400I deduced that the default nb voltage should be enough to overclock the cpu this far. However I notice on the forums that higher nb voltages are being used for overclocking to400x9.

If I am overclocking the cpu 400x9 is there any need to increase the northbridge voltage beyond default and if so can someone explain the logic to a newbie at overclocking.

If there is a need to increase nb voltage is there a way of differentiating instability on prime95 or OCCT that is secondary to northbridge vs cpu based instability.

thanks for any advice

[Clunk]

On both the X38 and X48, I have found that you only need to change the CPU voltage, DRAM voltage for the overclock that you are looking for.

These settings are for an E8400.

CPU Feature
Thermal Management Control: Disabled
PPM(EIST) Mode: Disabled
Limit CPUID MaxVal: Disabled
CIE Function: Disabled
Execute Disable Bit: Disabled
Virtualization Technology: Disabled
Core Multi-Processing: Enabled

Exist Setup Shutdown: Mode 2
Shutdown after AC Loss: Disabled
CLOCK VC0 divider: AUTO
CPU Clock Ratio Unlock: Enabled
CPU Clock Ratio: 9 X
Target CPU Clock: 3600Mhz
CPU Clock: 400
Boot Up Clock: AUTO
DRAM Speed: 400/800
Target DRAM Speed: 800Mhz
PCIE Clock: 100mhz
PCIE Slot Config: 1X 1X

CPU Spread Spectrum: Disabled
PCIE Spread Spectrum: Disabled
SATA Spread Spectrum: Disabled

Voltage Settings
CPU VID Control: 1.15v
CPU VID Special Add: 100.23%
DRAM Voltage Control: 2.19v
SB Core/CPU PLL Voltage: 1.51v
NB Core Voltage: 1.35v
CPU VTT Voltage: 1.211v - Note that this is slightly higher than the X38's 1.205v
Vcore Droop Control: Enabled
Clockgen Voltage Control: 3.45v
GTL+ Buffers Strength: Strong
Host Slew Rate: Weak
GTL REF Voltage Control: Disabled - Not needed yet.
x CPU GTL1/3 REF Volt: 110
x CPU GTL 0/2 REF Volt: 110
x North Bridge GTL REF Volt: 110

DRAM Timing
Enhance Data transmitting: AUTO
Enhance Addressing: AUTO
T2 Dispatch: Disabled

Clock Setting Fine Delay
Ch1 Clock Crossing Setting: AUTO
DIMM 1 Clock fine delay: Current
DIMM 2 Clock fine delay: Current
Ch 1 Command fine delay: Current
Ch 1 Control fine delay: Current


Ch2 Clock Crossing Setting: AUTO
DIMM 3 Clock fine delay: Current
DIMM 4 Clock fine delay: Current
Ch 2 Command fine delay: Current
Ch 2 Control fine delay: Current

Ch1Ch2 CommonClock Setting: Auto

Ch1 RDCAS GNT-Chip Delay: Auto
Ch1 WRCAS GNT-Chip Delay: Auto
Ch1 Command to CS Delay: Auto

Ch2 RDCAS GNT-Chip Delay: Auto
Ch2 WRCAS GNT-Chip Delay: Auto
Ch2 Command to CS Delay: Auto

CAS Latency Time (tCL): 5
RAS# to CAS# Delay (tRCD): 5
RAS# Precharge (tRP): 5
Precharge Delay (tRAS): 15
All Precharge to Act: AUTO
REF to ACT Delay (tRFC): AUTO
Performance LVL (Read Delay) (tRD): AUTO

Read delay phase adjust: Enter

Ch1 Read delay phase (4~0)
Channel 1 Phase 0 Pull-In: Auto
Channel 1 Phase 1 Pull-In: Auto
Channel 1 Phase 2 Pull-In: Auto
Channel 1 Phase 3 Pull-In: Auto
Channel 1 Phase 4 Pull-In: Auto

Ch2 Read delay phase (4~0)
Channel 2 Phase 0 Pull-In: Auto
Channel 2 Phase 1 Pull-In: Auto
Channel 2 Phase 2 Pull-In: Auto
Channel 2 Phase 3 Pull-In: Auto
Channel 2 Phase 4 Pull-In: Auto

MCH ODT Latency: AUTO
Write to PRE Delay (tWR): AUTO
Rank Write to Read (tWTR): AUTO
ACT to ACT Delay (tRRD): AUTO
Read to Write Delay (tRDWR): AUTO
Ranks Write to Write (tWRWR): AUTO
Ranks Read to Read (tRDRD): AUTO
Ranks Write to Read (tWRRD): AUTO
Read CAS# Precharge (tRTP): AUTO
ALL PRE to Refresh: AUTO


There is no one single answer to your question. With overclocking, it is always a case of try it and see.

If your setup requires a small bump in NB voltage, then so be it. If your CPU needs more voltage, don't worry, they are all unique and all have slightly different characteristics.

Anywhere after this speed, and you *may* require a touch more NB voltage.

Have a look at my overclocking guides, there is a DFI add on which you should find helpful for all the basics.

[ricgordon]

Thanks clunk
i was having instability in prime95 with my cpu voltage until it was up to about 1.34. (OCCT was reporting as stable at lower voltages). This seemed pretty high compared to what others haved been using for this cpu to 3600.
The error on prime95 was after about four hours and I wondered whether it could have been the northbridge. I notice that your settings include a higher nb voltage which I will try.
Temperatures seem to be ok although there is a significant difference between the smart guardian readout and realtemp they are both under 60.

[Clunk]

Oops, sorry, the NB voltage should have been at stock, I used the template that had settings from 450x9 - As I say, if the raised NB voltge works for you, then the jobs a good un

Also, if you are using four sticks of RAM, you may need to up the NB voltage a touch.

As far as software temp readouts go, just take them with a pinch of salt. Ignore smart guardian for CPU temps, stick to realtemp or coretemp

[ricgordon]

thanks again
the software readings are confusing for voltage as well
cpu-z shows my cpu voltage at 1.312 when in bios it is set to 1.29
smart guardian also says cpu voltge 1.31
? do I accept bios or cpu-z as the true value??

[Clunk]

The only real way of finding the correct voltages is with a DMM.

As most of the software reads differently, it's impossible to know what is correct unless you have measured properly with a DMM.

I am going to have a poke around this weekend and see what is correct for the vcore.

Also take into account that the Special VID setting, if left on AUTO will cause a slight overvolt.

[ricgordon]

gradually getting better with prime not failing until 6 hours at 1.31 on cpu-z. Must be the Special VID setting adding the voltage as when I checked the voltage readings in bios they were also higher than I had selected.
will continue to trial the different options and get back to you when stable
it appears my e8400 chip needs more volts than those lucky people that can overclock to 3600 on default