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Trying to understand voltages for Sandybridge and programs...

GregI

GregI

GregI

Associate
Joined
10 Dec 2007
Posts
1,866
I think I have messed up. I have tried to follow some guides but I get lost.

So I have a 2500k and a P67A-UD4. These are some screenshots I will try to explain. I have core temp for monitoring, cpu-z and intel burn test for stressing. I first tried a basic 36 core multiplier with stress. Can anyone explain why CPU-Z shows 1.068 v? Off screen CPU-Z shows 3600 Mhz as it should do as I set it in BIOS, but why is Core Temp showing 3309? Isn't that stock? And why 1.3210v? I understand that the VID is the initial voltage needed to start the PC? This should be lower right to guarantee longer life of the CPU, I think.

http://img853.imageshack.us/img853/3509/sam0313.jpg

Here is the next expert camera shot I took...

http://img94.imageshack.us/img94/6199/sam0314x.jpg

That shows the 3600 overclock. I think I did set 1.200 V as I wanted to see how low I could go for temps, DRAM voltage also shows 1.548 v when I set it to 1.500 in the voltage options....

Now onto some settings

http://img863.imageshack.us/img863/6942/sam0315w.jpg

Everything there is correct besides the low clock ratio right?

I followed those enabled/disabled stuff from a guide.

Next screenshot...

http://img715.imageshack.us/img715/8057/sam0316m.jpg

Now where on earth is it pulling 1.305 from when I stuck it to 1.200 v (what showed on the previous screen). You can also see the 1.500 RAM voltage I set which I mentioned before.

I then set the clock ratio to 41 (changed nothing else) and the vcore went up to 1.340v. Why the increase?

http://img204.imageshack.us/img204/5444/sam0317l.jpg

I then booted into Windows, CPU-Z shows the correct overclock of 4100 but still 1.068v and Core Temp is still a mess. Notice how in first shot it shows 827 x 4 then after a clock ratio change it shows 100 x 33.

http://img824.imageshack.us/img824/6001/sam0318v.jpg

If anyone can read and understand what to fix, I salute you.
 
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Quite simple

First of all, if you have a B3 version motherboard then CPU-z will not read your voltage correctly. It is reading the vtt.

If you do not have a B3 motherboard then you need to use the latest CPU-z and it will read your voltages correctly.

CoreTemp does not and will not pick up your correct MHz of the CPU. Just go to CPUID and download hardware monitor.

All the rest is just a waste of time. If you want to overclock your system it is real easy.

Lets start with a nice clean sheet shall we.
Set defaults in your BIOS.
If your ram has a XMP profile enable it in your BIOS by selecting XMP.
Once you have done that select manual - that will allow you to change the multiplier but leave your ram at the correct pre-programmed settings.
Now select your desired multiplier. If you have good cooling then 45 is perfect for 24/7
Leave all your voltages on auto.
Leave all your CPU settings just as they are. There is no need to disable the power saving modes with SB to achieve an overclock.
F10 and enter.
Boot into OS and enjoy your system at 4.5GHz
 
OK. I selected "fail safe defaults" and set the XMP profile. I had Disabled and Profile1.

I set the multiplier to 45 and booted. It would not boot (constant BIOS reboot). I took off the XMP profile and it booted up to Windows but the clocks seem to be screwed up and running at stock speeds.
 
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OK an update. I can run XMP profile but not at 45. The board will allow Windows to boot at 41 and it sets the vcore auto as instructed. I also enabled all the power saving features.
 
I can only boot at a 43 multiplier. Anything more on Auto fails. The 43 just completed a 15 burn test at a stress level of High so can't see why simply booting into Windows at 45 would be a trouble. Anyone got screenies to show me? :)

modez, I looked at that guide. One thing stood out from initial reading. "and a the usual 1.65V of DRAM Voltage". Now I look here at the sticky and it states "Memory - Intel recommend 1.50v plus/minus 5% which means 1.60v is the ideal safe maximum". Now if they can't get RAM voltage right (by being over the safe maximum), I heavily doubt trusting that guide with more complex stuff about voltage on the CPU.
 
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I have set everything to Auto again. The core voltage reported in BIOS is 1.320 and this is completely stable at 4.3 Ghz. I cannot boot with any voltage when the multiplier is over 43.
 
GregI said:
I have set everything to Auto again. The core voltage reported in BIOS is 1.320 and this is completely stable at 4.3 Ghz. I cannot boot with any voltage when the multiplier is over 43.
Click to expand...

A bit low for Sandybridge but perhaps that's the limit of your CPU.

Not all processors will overclock the same.
 
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Maybe. I just don't understand how I can be 100% rock solid at 4.3 Ghz but not even get past a boot screen at 4.5 Ghz. You would think the OS would boot up and even BSOD to tell me I have reached the limit.
 
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GregI said:
Maybe. I just don't understand how I can be 100% rock solid at 4.3 Ghz but not even get past a boot screen at 4.5 Ghz. You would think the OS would boot up and even BSOD to tell me I have reached the limit.
Click to expand...

Try more voltage. I wouldnt push it over 1.4volts for everyday running though personally. Some people wont even go over 1.35.
 
Thanks for the suggestions. I will try tomorrow (tired of it just now).

Just so I have it clear in my head, whatever the vcore in the BIOS states (see second pic I linked of 1.200) this is what is used for stability? How is the vcore then calculated when my cpu is idle and drops down to 1.6 Ghz?
 
GregI said:
Maybe. I just don't understand how I can be 100% rock solid at 4.3 Ghz but not even get past a boot screen at 4.5 Ghz. You would think the OS would boot up and even BSOD to tell me I have reached the limit.
Click to expand...

SB does not work like other CPU's have in the past.

My SB is rock solid Vantage pass at 5.724GHz. increase it by just 0.004 of a MHz and it fails completely.

It is unusual that you have not been able to get to 45x multi on auto. Does your BIOS allow you to change your VTT and PLL voltages. What I have noticed is that the relationship between those two voltages needs to be right. Too much and you can not boot into OS. To little and the same result.

My settings for 5.1GHz 8 hours Prime Stable

LLC1

VCore 1.44
Vtt. auto
PLL 1.760

If I raise the PLL above 1.860 my board will not boot.
If I raise the Vtt above 1.15 the board will not boot



Edit. The intel white paper indicates a vCore of 1.52 as the max. Not sure if that is for short bursts or safe for 24/7 as I only use my CPU for short periods of time I do not fuss about vCore too much.
 
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See for the PLL do you mean 1.760? My board has that auto at 1.800. OcUK says not to exceed 1.9v so should be OK there. My VTT is 1.050 v. Maybe this is why I can't do 45?

Out of curiosity I have been lowering my voltage to actually see how low I can go with 43. I have core voltage now at about 1.275 and it completed intel burn test (15 tests at high). My temps never went over 52c.

I also have Load-Line Calibration enabled. Should I disable this?
 
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You can leave it on. But unless you are really going to be stressing your CPU out at max there is no need to enable.

And yes I do mean 1.760 thank you for pointing that out to me.

What BIOS are you using? If you want to overclock your system more you will need to have the PLL overrider enabled. That is only found on some BIOS's but it is not recommended for 24/7 use.
 
I will disable it then and lower the voltage slightly. Having a fully stable overclock of 4.3Ghz with temps not exceeding 50c is pretty darn good for me. Will leave my Q6600 at 3ghz in the dust.
 
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