Now for the current emphasis on totally stock perf of the i9’s by the review sites, all the attention is on TDP but that’s just a gnat compared to the camel swallowed. NO site actually talked about and examined the latest feature of the i9, Thermal Velocity Boost TVB. By default Intel enables this but I see that only Asus boards enable this at defaults. The other boards I tested have this disabled even at defaults.
What this does is it reduces voltage guardbands depending on core temp. Traditionally, the voltage request by the proc is always based on worst case scenario TJMAX, meaning the voltage the proc thinks it needs for the frequency when temp is 100c. It is well-known that the cooler the chip runs, the lesser the voltage needed. Therefore TVB is opportunistically reducing power and temps. The behavior is quite linear and I observed the following on several samples.
TVB takes effect from 40~50x on 99k and 40 to 49x on 97k and 40 to 47x on 96k, simply 40x to single core boost ratio. The V/temp curve runs from 0c to 100c. For example 150mv delta between 100c and 0c for 50x, meaning every 1C drop from 100c VID requested will reduce by 1.5mv. The reduction is smaller as you go down to 49x, the smaller the ratio the smaller the reduction, and below 40x you get no reduction. This is good for most people running stock. You can try this yourself by noting the VID idle, and then unplug your water pump and let the core temp rise slowly, noting down the correlated temp/VID, and see what i'm talking about.
During OC, when you try to run adaptive mode voltage with this mechanism, you will need to change your perspective in how you set the ‘target adaptive voltage’ since you need to assume that’s the voltage you get when 100c and do the reduction to your lowest (usually ambient) temp and gauge what voltage is needed to be set. So if you set 1.35v for example, when you idle at 30c you will get maybe 1.25v instead. This can be confusing for many people, therefore we disable TVB once you customize a ratio. This is not to say you cannot exploit this mechanism to work for you during OC but you really need to find out your idle Vmin (lowest stable voltage). You can find this option in CPU internal power management in the bios and you can force it to enable during OC.
For those who want to check or try this on other boards, simply download r/w everything
http://rweverything.com/ and add CPU MSR 0x150
Access this register and set bit 63 to 1 and [39:32] to 18h:
https://ibb.co/gUyvUf
Bit 3 shows you if TVB is enabled or disabled (0=disabled). If TVB is disabled, simply flip the bit and use command 19 to write.
https://ibb.co/jCEDFL
https://ibb.co/muKDFL
Then you can see what the default stock behavior is really like. This will truly affect temperature, power consumption, boost frequencies when TDP is default, etc so those who want to dig deeper into ‘stock performance’ really needs to get this correct.
Problems? See this thread at archive.org.
just to let everyone know... it is only supported on 8th Generation CPU Processors and upwards..
