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CPU VID Does not affect Overclocking.

Emphacy

Emphacy

Emphacy

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I've known for a long time what CPU VID was, how to find it and why people say it effects the ability to overclock a CPU.

Thus, today, I decided to find out how VID (Voltage Identification) really worked and if possible how you change it.
It turns out that CPU VID isn't as simple as everyone thinks, and that a CPU doesn't just have 1 voltage identification level, it in fact, has 6 which vary between motherboards and systems.

Here's some information I found on another forum, some of which is said to be directly off the Intel website, but you need an account to view the databases.

The VID is hardcoded into each individual cpu, but it's not just one number; it's a range of 6 different VID levels and these levels are specific to each individual CPU. VID is not static and changes with power requirements. VID can fluctuate almost constantly to try to maintain the level programed into it during manufacturing.

I was just curious what CoreTemp actually reports, is it reporting the VID being used at the time, max VID, etc? VID is read from a sense line off one of the cpu pads, it seems like CoreTemp would have to be reading whatever VID level is in use at that time.
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Here's another quote in the same place which is direct from Intels website. I tried to access any information myself, but it view it, it asked me to login.

Individual processor VID values may be calibrated during manufacturing such that two devices at the same core speed may have different default VID settings. This is reflected by the VID Range values provided in Table 5.

The processor uses six voltage identification signals, VID[6:1], to support automatic selection of power supply voltages.

The processor provides the ability to operate while transitioning to an adjacent VID and its associated processor core voltage (VCC). This will represent a DC shift in the load line. It should be noted that a low-to-high or high-to-low voltage state change may result in as many VID transitions as necessary to reach the target core voltage.
Transitions above the specified VID are not permitted. Table 5 includes VID step sizes and DC shift ranges. Minimum and maximum voltages must be maintained as shown in Table 6 and Figure 1 as measured across the VCC_SENSE and VSS_SENSE lands.
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This explains why my Q6600 despite it's low VID of 1.2V on my system still doesn't overclock very well, in fact, after 3GHz it's unstable. Must be my motherboards voltage regulators which also explains why you can clock better on some motherboards, than on others.

What do you guys think?
 
I've always considered it a reasonable indicator of overclockability and no more. Typically CPUs that have been binned with a lower VID do tend to have a higher chance of being better overclockers but theres no hard and fast rule.

Same with the week/batch often there are batches that have a higher number of good clockers in that batch but its not a hard fast rule. i.e. I had a week 27 E6600 which was talked about as being a good batch and it did indeed overclock nicely, but its still luck of the draw.
 
Not all CPU's are created equal. Some require more voltage than others. All the VID does is tell the motherboard/PSU how much juice to give it.

As said above, generally speaking the lower the default voltage, the better the chip tends to overclock which makes perfect sense if you think about it.
 
Rroff said:
I've always considered it a reasonable indicator of overclockability and no more.
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As did I, until I discovered 955s shipping with VIDs of 1.4v could be undervolted to 1.32v and be completely stable, or oveclocked to 3.8 at 1.35v (0.05v under vid).

Intel VIDs seem closer to the mark, though multiple levels in sandy seem to have complicated matters.
 
dbmzk1 said:
Not all CPU's are created equal. Some require more voltage than others. All the VID does is tell the motherboard/PSU how much juice to give it.

As said above, generally speaking the lower the default voltage, the better the chip tends to overclock which makes perfect sense if you think about it.
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You never actually know what the CPU's lowest VID is though. CoreTemp will only tell you the current VID in use, not the minimum.

And since this ranges from motherboard to motherboard, you will never know the CPU's lowest VID and since the same range of 6 VID levels are present in each CPU how do you know which one the CPU will choose in your setup.

It may need a 1.2V VID in one persons PC and a 1.1 in someone elses, and since this is effected by a motherboards voltage regulation ability it could be any VID in the 6:1 range.
 
As has been said, it always has been a hit and miss thing.
But one thing is for sure, a lower Vid chip is always hotter than a higher vid chip.
So any clock from a lower Vid chip is limited by the extra heat it generates.
 
Emphacy said:
Must be my motherboards voltage regulators which also explains why you can clock better on some motherboards, than on others.

What do you guys think?
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I've always managed better overclocks on socket 775 equip using good quality Motherboards with low VID Q6600's or Q9650/Q9550's, so to an extent I agree.
 
The VID gives a general overview on how well the cpu may overclock. Low VID cpu generally means that it will require less volts to overclock to same frequency/speed compared to high VID cpu.

Ofcourse it depends on mobo aswell as to whether it is 4,6,8 or 16-phase motherboard. A higher phase mobo will have more efficient voltage regulator that will supply and smooth out the required voltage to cpu. Thus overclocking will be easier and more stable on such mobo.:cool:


One thing that many people seem to forget is that mobo northbridge chipset especially in skt 775 can also have impact on overclocking. A chipset that has better cooling will be able to withstand high overclocks as this means it can operate at lower temps as interface to cpu. If northbridge chipset gets very hot then system can also crash as in my experience.
 
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Emphacy said:
You never actually know what the CPU's lowest VID is though. CoreTemp will only tell you the current VID in use, not the minimum.

And since this ranges from motherboard to motherboard, you will never know the CPU's lowest VID and since the same range of 6 VID levels are present in each CPU how do you know which one the CPU will choose in your setup.

It may need a 1.2V VID in one persons PC and a 1.1 in someone elses, and since this is effected by a motherboards voltage regulation ability it could be any VID in the 6:1 range.
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That's not how a VID works?

They can have up to 6 VIDs to account for all the different P-States a CPU may have. Intel usually only have 2, but i've seen AMD CPU's with 4+ before.

I've never ever known a CPU of a given VID to run at a different voltage when placed into any number of motherboards. Motherboards may have an impact on how much voltage is required, but this is why VIDs usually have some headroom to them.

If you want to know what the actual VID of a CPU is then that should be the voltage the BIOS selects when everything is on default. Windows will report different of course due to what VID is current in use due to EIST/C&Q.
 
DarkBahamut said:
That's not how a VID works?

They can have up to 6 VIDs to account for all the different P-States a CPU may have. Intel usually only have 2, but i've seen AMD CPU's with 4+ before.

I've never ever known a CPU of a given VID to run at a different voltage when placed into any number of motherboards. Motherboards may have an impact on how much voltage is required, but this is why VIDs usually have some headroom to them.

If you want to know what the actual VID of a CPU is then that should be the voltage the BIOS selects when everything is on default. Windows will report different of course due to what VID is current in use due to EIST/C&Q.
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I agree.

VID is also usually referred to as the stock voltage which has been programmed in a given cpu for it to run at stock speed. Fo example My Q6600 has VID of 1.2625V and this is what bios reports when I place it in my mobo. If I place it in any other mobo, bios of that mobo will report the same VID as this is the native stock speed voltage for my Q6600.

However when it comes to overclocking, it is a slight different story. As mentioned before mobo can aslo affect overclocking. My Q6600 in a high-phase mobo will require less volts to overclock to 3.0Ghz compared to a low-phase mobo. In the latter case I will require more voltage to stabilise at 3.0Ghz as the voltage regulator isn't as efficient in the latter case.
 
My q6600 had a middle range vid, (1.2750), was a pretty decent overclocker, 3.8ghz @1.51 vcore. My q9550 that replaced it had a vid of 1.200, clocked to 3.8ghz on 1.216 vcore. Both were clocked on an asus p5q deluxe, good high phase board with a very cool running nb.
 
Emphacy said:
You never actually know what the CPU's lowest VID is though. CoreTemp will only tell you the current VID in use, not the minimum.

And since this ranges from motherboard to motherboard, you will never know the CPU's lowest VID and since the same range of 6 VID levels are present in each CPU how do you know which one the CPU will choose in your setup.

It may need a 1.2V VID in one persons PC and a 1.1 in someone elses, and since this is effected by a motherboards voltage regulation ability it could be any VID in the 6:1 range.
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No.

Each individual CPU only has 1 and it's fixed and doesn't change regardless of motherboard or other components.

They may, as stated, have several VID's for their different power states, ie when running slower using Speedstep, etc, but for the purposes of this discussion it's the main full speed/full load VID that's important.

VID = that particular CPU's default stock voltage.
 
dbmzk1 said:
No.

Each individual CPU only has 1 and it's fixed and doesn't change regardless of motherboard or other components.

They may, as stated, have several VID's for their different power states, ie when running slower using Speedstep, etc, but for the purposes of this discussion it's the main full speed/full load VID that's important.

VID = that particular CPU's default stock voltage.
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Well thanks for clarifying this, and to others above, this is why I asked. My Q6600 isn't a good clocker, so checked out VID.
Is 1.3125V a low VID for this kind of processor? It could either be down to the VID or my Northbridge getting a bit toasty/ my cheap motherboard like said above.

Thanks for the input and to clarify things.
 
Emphacy said:
Well thanks for clarifying this, and to others above, this is why I asked. My Q6600 isn't a good clocker, so checked out VID.
Is 1.3125V a low VID for this kind of processor? It could either be down to the VID or my Northbridge getting a bit toasty/ my cheap motherboard like said above.

Thanks for the input and to clarify things.
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Your VID is approaching the high VID number. The highest I have seen is 1.3250v VID.

What motherboard are you using?
 
Emphacy said:
Well thanks for clarifying this, and to others above, this is why I asked. My Q6600 isn't a good clocker, so checked out VID.
Is 1.3125V a low VID for this kind of processor? It could either be down to the VID or my Northbridge getting a bit toasty/ my cheap motherboard like said above.

Thanks for the input and to clarify things.
Click to expand...

Definitely towards the higher end. Depending on the stepping they range from 1.1125v and 1.1625v to 1.325v

Doesn't necessarily mean it will be a bad clocker by default. As just asked, what motherboard do you have? Also when clocking make sure you're not pushing your RAM too far either.
 
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MSI P43 Neo-F Motherboard at current, wanting to go for a Rampage Extreme if I can find one...

The memory is only 800MT/s with a maximum clock of 920MT/s so I always set the ratio to 1:1.25 so memory is at 667MT/s before overclocking. I then clock the Q6600 to something like 3.3 when the RAM reaches 915MT/s.

It boots up fine and all but after about 5/10mins of gaming is BSOD's.
 
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