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VID Question

M

mercury529

Limp Gawd
Joined
Dec 19, 2007
Messages
173
Hey Everyone,

I recently got my Q6700. I checked its VID using CoreTemp. It is listed as 1.3250v, which I was reasonably disappointed about. With CPU voltage set to Auto in the bios of my Asus P5Q Pro, voltage registered as 1.28v in CPU-z. When I set the voltage in the bios to 1.3v, it registered as 1.28v in CPU-z. When I set the voltage in the bios to 1.31875v, it registered as 1.296v. I had a few questions.

1.) It appears that the Auto voltage for the CPU is 1.30v not 1.3250v. Am I interpreting it correctly?
2.) Is it normal for the voltage of the Auto setting to vary from the VID?
3.) If it is not normal, does it indicate anything about the over-clockability of the chip? (So far I have hit 3.2ghz on 1.31875v)
 
The VID is the "stock" vCore for each chip, and it varies from chip to chip based on Intel's testing procedures. The VID will tell the motherboard: "This is the voltage I require at stock speeds when the VCore setting is on 'Auto' for proper operation." Nothing more. It is said that a lower VID value will yield better overclocks.
 
1) The voltage is being set to 1.325v. However, there is always a slight drop in the actual voltage compared to what it's set at. The VID is still 1.325v.

2) Again, it's not the Auto setting that's exhibiting the variation, it's the actual voltage. The Auto setting is putting the voltage at 1.325v, but the actual voltage ends up being slightly lower. This is called Vdroop, and it exists for all voltage settings, all CPUs, and all motherboards.

3) The VID has been shown to not significantly affect potential overclocks. People have gotten low VID chips that are poor overclockers, while there are a lot of 1.325v VID chips that do 3.6GHz easily. In short, the VID doesn't matter all that much.
 
Thanks for the replies guys.

Zero82z:

I understand the vdroop concept, but isn't the vdroop fairly consistent? I was consistently getting a voltage of 1.28v in CPU-z with a manual setting of 1.30v, and I was consistently getting a voltage of 1.296v in CPU-z with a manual setting of 1.31875v. Why would manually setting the 1.31875v result in a higher voltage in CPU-z than the Auto voltage at stock speeds (which should be setting it to 1.3250v)?
 
Zero82z said:
Vdroop is not consistent.
Click to expand...

But would it consistently drop from Auto (1.3250) to 1.28v when it consistently drops from 1.30v Manual to 1.28v and consistently drops from 1.31875 to 1.296v? That would mean I'd be consistently getting more voltage from a lower voltage setting and the same voltage from a setting that is .025 volts higher.
 
Like I said, Vdroop is not consistent. The variations are unpredictable, and considering the very low variations in the settings you're using, it isn't surprising that you're getting actual voltages that are fluctuating over a small range.
 
I stepped through a fairly wide range of voltages (1.25v up to 1.3750v), and there wasn't a single time where raising the voltage in the BIOS resulted in a lower voltage reading in CPU-z. And the readings registered in CPU-z have been perfectly consistent for me (voltage at idle is always the same for any given BIOS setting).
 
The fact is that sometimes, the voltage readings are weird. That's simply how it is. If I were you, I wouldn't worry about it, since it really doesn't make a difference in the grand scheme of things.
 
Is it normal to be able to get a stable overclock (3.2 ghz over 2.66 stock) at voltage under the VID (1.31875v stable with the 1.3250 VID)?
 
mercury529 said:
Is it normal to be able to get a stable overclock (3.2 ghz over 2.66 stock) at voltage under the VID (1.31875v stable with the 1.3250 VID)?
Click to expand...

Yes, that's normal. My Q9550 is the same way. Stock speed is 2.83Ghz and VID is 1.25v, but I am able to OC to 3.4Ghz at under my VID.
 
Well scratch that. After 19 successful hours running prime95, it failed. Guess I'll have to go up another step.
 
mercury529 said:
Well scratch that. After 19 successful hours running prime95, it failed. Guess I'll have to go up another step.
Click to expand...

Lol, don't stress too much (no pun intended). If your system passes for that long but still fails, you could very likely get by on that OC without changing anything else.
 
I was running my tests on Large FFT if that matters.

So what causes a CPU to fail a test? Do CPUs running at stock ever fail when stressed for 12+ hours? Can a single failure, like the one that occurred in prime95, take down a system?
 
mercury529 said:
Can a single failure, like the one that occurred in prime95, take down a system?
Click to expand...

Yes. If you happen to be running an application that depends on that specific operation that caused your CPU to make an error, it's possible for your system to crash or for whatever data your CPU happens to process at that moment to become corrupted. If you really want to test for stability, download and run IntelBurnTest. It uses an app that Intel themselves actually use to stress-test their CPUs, so it's a very good indicator of stability. 20 runs is generally sufficient to ensure a stable system.
 
IBT has passed 10-20 runs for me and then Prime95 has failed directly after. I'll never rely on IBT alone.
 
mercury529 said:
I was running my tests on Large FFT if that matters.

So what causes a CPU to fail a test? Do CPUs running at stock ever fail when stressed for 12+ hours? Can a single failure, like the one that occurred in prime95, take down a system?
Click to expand...

Large FFT failures can mean either the CPU or the RAM is at fault. If Large FFT fails, try Small FFT right after. Small FFT's are small enough to fit in the CPU's cache, so the RAM isn't needed. If Small FFT fails, then it's almost completely certain that the CPU is the fault. If Small FFT doesn't fail and Large FFT does, then it's almost certain it's the RAM.
 
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