Intel TVB Voltage Optimisation. Worth enabling it?

evo4ever86

evo4ever86

evo4ever86

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Hello all.

I noticed a feature in my ASUS mobo BIOS called "TVB Voltage Optimisation" I'm not quite sure how it works and would it make an overclock unstable? Can anyone shed any light on this technology? Cheers guys!
 
Thermal Velocity Boost. It's a feature of 9 series CPUs. Seems that it's like a reverse boost facility - as the chip gets cooler, it applies a negative offset to voltage. So the lower your temperature, the lower the voltage applied for a given clock speed. This is because voltage required for silicon to function within spec goes up with heat. Net result is a well-cooled chip should stay cool, I guess. That's all i could find but there are more specifics online :)
 
LuckyBenski said:
Thermal Velocity Boost. It's a feature of 9 series CPUs. Seems that it's like a reverse boost facility - as the chip gets cooler, it applies a negative offset to voltage. So the lower your temperature, the lower the voltage applied for a given clock speed. This is because voltage required for silicon to function within spec goes up with heat. Net result is a well-cooled chip should stay cool, I guess. That's all i could find but there are more specifics online :)
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So I guess its only worth having it enabled on a cold winters night under an open window?
 
evo4ever86 said:
So I guess its only worth having it enabled on a cold winters night under an open window?
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I wouldn't say that, low temperatures means well-cooled not refrigerated! Like many new features i expect it will become obvious over time how useful it is. It has the potential to be handy though, for anyone with good cooling who isn't always running at 100% load.
 
LuckyBenski said:
I wouldn't say that, low temperatures means well-cooled not refrigerated! Like many new features i expect it will become obvious over time how useful it is. It has the potential to be handy though, for anyone with good cooling who isn't always running at 100% load.
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I'll enable it and see how it goes. Cheers guys.

EDIT: I've heard it only works for 9th gen CPUs IE the 9000-series CPUs, is this true?
 
The basic silicon principle is that more voltage is needed at higher temperatures due to the increased resistance. Where is it documented that Haswell VID worked the opposite way? I hadn't heard that.
 
LuckyBenski said:
The basic silicon principle is...
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A basic principle would include temperature inversion ie gate threshold voltage as well as mobility.

Intel doesn't publicly provide much information on the FIVR and maybe doesn't provide much under NDA either going by HWiNFO and HWMonitor providing incorrect core VID values from the early days. One can however test one's own CPU for temperature vs VID with set ratio and load. Internal VID tables are usually different not only per CPU of the same model but per core of the same CPU. For instance my Haswell-EP CPU varies something like 15mV over 40C as does my i7-4600m but my i7-4700MQ changes as much as 50mV over a 60C delta (35C-95C) which can cause some confusion with adaptive mode and AVX as the extra voltage applied by AVX is offset by the change in VID resulting in what appears as no change.

You might find some vague data in the datasheet such as from 8th and 9th Generation Intel® Core™ Processor Families and Intel® Xeon® E Processor Family Datasheet, Volume 1 of 2
7.1.2 V CC Voltage Identification (VID)
The processor uses three signals for the Serial Voltage IDentification (SVID) interface
to support automatic selection of voltages. The following table specifies the voltage
level corresponding to the 8-bit VID value transmitted over serial VID. A ‘1’ in this table
refers to a high voltage level and a ‘0’ refers to a low voltage level. If the voltage
regulation circuit cannot supply the voltage that is requested, the voltage regulator
should disable itself. VID signals are CMOS push/pull drivers. Refer Table 7-19 for the
DC specifications for these signals. The VID codes will change due to temperature and/
or current load changes in order to minimize the power of the part. A voltage range is
provided in Section 7.2. The specifications are set so that one voltage regulator can
operate with all supported frequencies.
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Did you read the product brief I linked earlier? The 8th and 9th gen datasheet also says much the same for TVB
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So basically meant for giving an additional turbo boost when temperatures are low enough.

 
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