Raising Southbridge\SB voltage... what for?

[Punisher!]

I was asking myself when SB voltage raise should be useful. In which cases?

I have now it on Auto with a 3TB RAID0.

[arroyo]

Rising SB voltage helps me stabilizing OC after HTT=250MHz. If you have a RAID or you use SATA3 device rising this voltage to 1.2V is a must.

[Punisher!]

Rising SB voltage helps me stabilizing OC after HTT=250MHz. If you have a RAID or you use SATA3 device rising this voltage to 1.2V is a must.

I am @250Mhz. So 1.2V in stead of 1.1V?

[wez]

I am @250Mhz. So 1.2V in stead of 1.1V?

If you have no stability issues, I see no reason to raise any voltages

[cmanser]

+1 - cooler is better.

If you have no stability issues, I see no reason to raise any voltages

[BeepBeep2]

On 790 chipsets and SB750 it was suggested you raise SB volts a tad if running RAID 0.

[Punisher!]

If you have no stability issues, I see no reason to raise any voltages

I actually have sporadics IRQ_NOT_LESS_OR_EQUAL blue screens.

[BeepBeep2]

I actually have sporadics IRQ_NOT_LESS_OR_EQUAL blue screens.

This usually points to ram, however it might be in your best interest to raise SB voltage from 1.1 to ~1.15v and see if it fixes the problem.

If not, I would start looking at RAM and CPU_NB stability.

[Punisher!]

This usually points to ram, however it might be in your best interest to raise SB voltage from 1.1 to ~1.15v and see if it fixes the problem.

If not, I would start looking at RAM and CPU_NB stability.

Thanks a lot.

Tried @1.15V, nothing changed, so I am starting to retest overclock without Load Line Calibration. Which voltage is usually required for a NB frequency of 2500Mhz? (1075T here)

[wez]

Which voltage is usually required for a NB frequency of 2500Mhz? (1075T here)

From stock volts and a few notches up. Shouldn't really need to raise it a whole lot for 2500mhz. But will vary between chips ofc.

[Punisher!]

From stock volts and a few notches up. Shouldn't really need to raise it a whole lot for 2500mhz. But will vary between chips ofc.

Some numbers?

[wez]

Some numbers?

I wouldn't think you'd need more than 1.2, but really, trial and error are the best way to find out. Lowest possible cpu-nb volt will help keep heat away and allow for higher cpu clocks. So its worth the work

[gOtVoltage]

I actually have sporadics IRQ_NOT_LESS_OR_EQUAL blue screens.

I Rarely touch the SB unless my raid needs it above 270htt or FSB ill up it a little
Most of the time its the lack of volts from CPU to NBchipset....Not the CPU/NBvid. IF you run over 4gigs of ram and use all four slots for memory try raising the CPU to Nb voltage.. this is the setting which helps the ram stabilize and usually needs boosting when filling all your ram slots on AMD cpu's. This is becuse more ram needs more volts to be come stable since the IMC is in the CPU .

hence try using more on the CPU NB for the mobo and see what happens. Then you move onto the IMC side which would be CPU nbvid usually 1.2v - to 2.5v is good for 2800 nb depending on ram speed and cpu used.

IRQ not less or Equal....... is usually IMC Ram related and can be buggy stock. It all comes down to how friendly your bios and ram settings are.
Raise any voltages in small steps and you can usually overcome this .

In the end it Sometimes means you are at your max on the hardware your using.
Thus you could also try a lower ram freqency, lower NB freqency or looser timing.
Then retest while using the same voltages you had in the begining .

Youll be surprized/ that sometimes just one ram setting could break the Easy button:P

[Punisher!]

Thanks a lot for your feedback.

BTW what do you mean by "lack of volts from CPU to NBchipset....Not the CPU/NBvid"? So NB Voltage? Not the CPU\NB?

Anyway actually my RAM are at stock even with the overclock I have on signature so they shouldn't be a problem. CPU\NB could be, but I can't understand what do you mean by "CPU to NB voltage".

Thanks. Goodbye.

I Rarely touch the SB unless my raid needs it above 270htt or FSB ill up it a little
Most of the time its the lack of volts from CPU to NBchipset....Not the CPU/NBvid. IF you run over 4gigs of ram and use all four slots for memory try raising the CPU to Nb voltage.. this is the setting which helps the ram stabilize and usually needs boosting when filling all your ram slots on AMD cpu's. This is becuse more ram needs more volts to be come stable since the IMC is in the CPU .

hence try using more on the CPU NB for the mobo and see what happens. Then you move onto the IMC side which would be CPU nbvid usually 1.2v - to 2.5v is good for 2800 nb depending on ram speed and cpu used.

IRQ not less or Equal....... is usually IMC Ram related and can be buggy stock. It all comes down to how friendly your bios and ram settings are.
Raise any voltages in small steps and you can usually overcome this .

In the end it Sometimes means you are at your max on the hardware your using.
Thus you could also try a lower ram freqency, lower NB freqency or looser timing.
Then retest while using the same voltages you had in the begining .

Youll be surprized/ that sometimes just one ram setting could break the Easy button:P

[gOtVoltage]

ITS THE nORTHBRIDGE VOLTAGE SETTING USUALLY CALLED( CPU NB) ..

(CPU NB) is mother board Nothbridge ...(lack of volts here, means you need to raise this voltage . Once all slots are filled or high gig ram is used. Some times ther isnt enuff volts suppliied at jdec to run with out errors when the cpu is overclocked and even stock in some cases.)

More so you need to up the voltages on CPU/NB or CPUvid when your overclock uses the least amount of VCORE on the CPU or you are at the Max Clocks and cant raise Vcore. .

The (CPU nbvid) is the CPU's voltage for IMC..usually i raise this to get higher Nb Freqency above 2600mhz when using a lot of ram or even higher ram freqencies.

Hmm if you are using 4x1 gigs, (all four slots), or even 8gigs 2x4gigs( two slots), you may need to raise the NB volts for the mother board chipset to be happy .

Raising the NB usually helps stabilize the ram if you are using a higher htt or CPU multi than stock. I have seen Ram run at stock JDEC on AMD setups and be unstable , 4x2gig and 4x4gig kits do this a lot.

Mostly because the NB chipset voltages are set to low by the Bios when all slots or high freqency/high gig ram was used. they are desighed to run stock volts up to 4 to 8 gigs on all slots. This means if your overclocking you need to give the ram some more jiuce.

Even too tight of ram timing or to high freqency can be over come.
Just tweaking the NB chipset or CPUnbvid voltages can make or break that OC and it dosnt take much.

[Punisher!]

Ok mate, I supposed it to be just "Northbridge" voltage and from your description it is. So you are talking about Northbridge voltage (CPU\NB is CPU IMC related here).

I raised it a little bit seeing I am @250Mhz bus. Should I raise it more? How much?

Thanks.

ITS THE nORTHBRIDGE VOLTAGE SETTING USUALLY CALLED( CPU NB) ..

(CPU NB) is mother board Nothbridge ...(lack of volts here, means you need to raise this voltage . Once all slots are filled or high gig ram is used. Some times ther isnt enuff volts suppliied at jdec to run with out errors when the cpu is overclocked and even stock in some cases.)

More so you need to up the voltages on CPU/NB or CPUvid when your overclock uses the least amount of VCORE on the CPU or you are at the Max Clocks and cant raise Vcore. .

The (CPU nbvid) is the CPU's voltage for IMC..usually i raise this to get higher Nb Freqency above 2600mhz when using a lot of ram or even higher ram freqencies.

Hmm if you are using 4x1 gigs, (all four slots), or even 8gigs 2x4gigs( two slots), you may need to raise the NB volts for the mother board chipset to be happy .

Raising the NB usually helps stabilize the ram if you are using a higher htt or CPU multi than stock. I have seen Ram run at stock JDEC on AMD setups and be unstable , 4x2gig and 4x4gig kits do this a lot.

Mostly because the NB chipset was set to low by the Bios when all slots or high freqency/high gig ram was used. Even too tight of ram timing or to high freqency can be over come by tweaking the NB chipset or CPUnbvid.

[BeepBeep2]

gOtVoltage, you are posting some conflicting information...

[AlleyViper]

Yup, for simplicity's sake, CPU_NB VID usually refers to IMC while the Chipset only as NB VID. If you prefix CPU on the later things get messy, even if the intention is "CPU to NB" (path) and not as CPU's NB (integrated part) as commonly used around here.

[Punisher!]

Yup, for simplicity's sake, CPU_NB VID usually refers to IMC while the Chipset only as NB VID. If you prefix CPU on the later things get messy, even if the intention is "CPU to NB" (path) and not as CPU's NB (integrated part) as commonly used around here.

Yeah.


Anyway, here it comes the strange thing:
I tested the whole day with Prime95 (testing 6+gb of RAM, yesterday), no problems at all... today I start the PC, I start the Prime95 (so at cold boot), after few minutes blue screen.

Seeing CPU\NB and CPU voltages are already quite high (1.25V and 1.4V respectively), in which would you bet to?

NB Voltage, currently at 1.15V (bus 250Mhz, HTT default)? or
SB Voltage, currently at 1.10V (stock)?
Bad RAMs (stock with a slight overvolt too)?
And what about CPU VDDA and Northbridge 1.8V? Are they fine on Auto?

[AlleyViper]

Was that BSOD a common memory problem like IRQ_NOT'?
What is your CPU_NB speed? Considering your sig stating 2.5GHz + 8GB, 1.25V doesn't look that high if you have a poor IMC. Instead of raising its voltage, you might try to check stability at 9X 1.25V to pin it as a CPU_NB problem, as it should suffice for 2.25GHz.

[Punisher!]

Was that BSOD a common memory problem like IRQ_NOT'?
What is your CPU_NB speed? Considering your sig stating 2.5GHz + 8GB, 1.25V doesn't look that high if you have a poor IMC. Instead of raising its voltage, you might try to check stability at 9X 1.25V to pin it as a CPU_NB problem, as it should suffice for 2.25GHz.

Yeah it was (always "Machine Over" or IRQ_NOT_LESS_OR_EQUAL).

As I have already written before (it is on the signature too) my CPU\NB frequency is 2500Mhz and my current voltage is 1.23V (I think it is even much more than enough).


Anyway I think I found instability cause:
the problem is that the Q-FAN function just doesn't work in the first minutes of cold booted PC. I have just tried to monitor CPU temp. and during the first minutes of Prime95 it had gone even @85°C because the CPU Fan just stayed at the idle cycle. It seems it doesn't monitor the CPU temp. to regulate the CPU fan speed during the first minutes of PC on. Np after few minutes, it started to go like hell (because I set full cycle is over 50°C) and the PC finally become stable. Now the question is: why the hell Q-FAN does not work during the first minutes?

[gOtVoltage]

Ok please forgive me, With all the New Boards every Mobo manufacture lables the Bioses different so ill show you My FXA990 UD5 Bios ..

24/7
OC on UD5 with FX6100 .
The CPU NBvid and NB voltage for Chipset is all ive had to tweak for this OC.

This Bios is no way optimal and COre Boost or CPU Boost dosnt turn off. Lots of bugs that ive worked around. Once a better Bios rolls out this chip ill tweak with voltages a little more.




The NothBridge Voltage also refered to as CPU/NB on other Bioses ..yes thats correct and it can get confusing..This setting varies between mobos and is for NB chipset only. This will help your ram get stable when running high gigs or when all slots are filled. Again This is not the CPU IMC its the Chipset to CPU bridge. I run stock or up to 1.2v if needed.


The RED BOX are the voltages im reffering too



Next

CPU NBvid voltage this is the one most people change for the CPU IMC.
This is for the IMC and NB freqency on the CPU ..You will only raise this one for stabilizing the IMC and or running more than 2500mhz NB. I usually dont go above 1.35v. Except for massive Clocking bench runs .

Both of the Two voltages are important for a good OC.. Sorry if its confusing,thank AMD for that since manufactures label theses two voltages in different ways across numerouse Mobos.

I play with both settings and the( SB voltage) In all i almost never touch the SB untill 270htt plus.. you only need a small amount to go higher on these new mobos.

Normally i keep it at 1.35v or lower even at 5000mhz this will be enuff.

[gOtVoltage]

Yeah it was (always "Machine Over" or IRQ_NOT_LESS_OR_EQUAL).

As I have already written before (it is on the signature too) my CPU\NB frequency is 2500Mhz and my current voltage is 1.23V (I think it is even much more than enough).


Anyway I think I found instability cause:
the problem is that the Q-FAN function just doesn't work in the first minutes of cold booted PC. I have just tried to monitor CPU temp. and during the first minutes of Prime95 it had gone even @85°C because the CPU Fan just stayed at the idle cycle. It seems it doesn't monitor the CPU temp. to regulate the CPU fan speed during the first minutes of PC on. Np after few minutes, it started to go like hell (because I set full cycle is over 50°C) and the PC finally become stable. Now the question is: why the hell Q-FAN does not work during the first minutes?

You may need to play around with differnt ram dividers and your PRIME at 85c is high.

IM water cooled and Heat is no problem.. You May have IRQ error fron to much heat under prime causing the IMC to (IRQnot less or Equal) error.

[Punisher!]

You may need to play around with differnt ram dividers and your PRIME at 85c is high.

IM water cooled and Heat is no problem.. You May have IRQ error fron to much heat under prime causing the IMC to (IRQnot less or Equal) error.

Problem is temp., but why is it just when PC is just started?

I mean: why the damn CPU fan doesn't work properly in the first minutes of PC on?

With CPU fan @100% max temp. is 69°C and I have no problems at all.

[gOtVoltage]

Sounds like you have a smart fan option or a PWM fan that slowly ramps up with speed. I always use a fan and heatsink that runs at 100% when using Aircooling

Things You can xcheck if you have a smart fan bios. Disabling all Smart Fan Options . Make shure your Fan is set to run 100% .Turning them all to Disabled including the Temp warning overheat usually defaults to 100% fan speed ..This Should run your Fan at 100% all the time. Make shure you are plugged into CPU fan header on Mobo . You may also want to remount the Fan/Heatsink with a good thermal paste like MX4 or something after you figure out the fan speed problem if things dont get better heat wise..

One of The first things i do before i up my OC is make shure the cooling is up to par . Ill slowly ramp OC and Voltages watching the temps .Sometimes Less voltage can get a higher OC , usually because the CPU will be cooler. On the other hand, Some chips prefer more volts for the same clocks than others and run as cool .

Not using enuff Vcore on the CPU will almost always get you a IRQ error even if its cool.