05-30-2018 02:58 PM
06-28-2018 11:54 AM
An update to my all core boost woes. I saw that there was a new 0903 BIOS for the motherboard with manufacturer implemented Meltdown/Spectre fixes. So I flashed the new BIOS.
That forced a completely new and virgin BIOS configuration so I lost all my previous user profiles. The BIOS set up the memory and core clocks differently than what I had used before. It achieved the XMP 3000 memory setting by changing to a 125Mhz BCLK setting and an Sync All Cores multiplier of 32. That accomplished a cpu core clock of 4000Mhz and the expected 3000Mhz memory strap of the XMP profile of the kit.
But what I found in the OS was that I had my all core boost again at the normal system clock of 4000Mhz. But the BIOS says to use if possible a standard front side bus frequency of 100Mhz and achieve the desired core clock and memory strap settings with a higher multiplier. This is how I had the system set up previously. 100 Mhz BCLK and 42 multiplier for 4200Mhz cpu clock and the XMP 3000 Mhz memory strap.
When I did that though I lost my all core boost again and was back again with the original problem of only two cores boosting to 4000Mhz and the rest at 3800Mhz. All the BIOS settings were set by default to Auto just as before.
As soon as I went back to the BLCK of 125Mhz and the multiplier of 32, I got my all core boost back again at 4000Mhz. So I set up a 34 Sync All Cores multiplier for a derived 4250Mhz cpu core clock and the XMP 3000 memory profile. I was able to get my same Vcore voltage back by setting a manual voltage of what I was running previously with an Auto with Offset voltage setting.
So once again I am boosting all cores at my desired core clocks.
So, there is definitely a difference between what the cpu exports in the MSR registers to the OS when achieving the desired cpu Turbo Boost settings via a BCLK of 125Mhz and one of 100Mhz. The 100Mhz BCLK setting prevents a all core Turbo Boost with the default intel_pstate scaling driver and performance governor. So for anyone that lost their all core Turbo Boost with the new 4.15.0-20 kernels, this is the way to get it back.
[Edit] Addendum. What this accomplished was reducing my BLC cpu task completion times from 51 minutes down to 32 minutes. Now the Intel system can run the BLC cpu tasks as fast as the Ryzen systems.]