MAMEWorld Forums - EmuChat - Re: New MAME 0.192 benchmarks

> Some things are definitely confusing, like what is "Max Non Turbo Boost Ratio"?

Max Non Turbo Boost Ratio (37x) is the base CPU multiplier. I believe speeds for sub-units within the chip are based off this ratio. This is also where the Processor Base Frequency (3.7 GHz) comes from. According to Intel...

Processor Base Frequency describes the rate at which the processor's transistors open and close. The processor base frequency is the operating point where TDP is defined. Frequency is measured in gigahertz (GHz), or billion cycles per second.

If you disabled the Turbo Boost feature in the Intel XTU program, your CPU would max out at 3.7GHz.

More info on your CPU from Intel:
https://ark.intel.com/products/126684/Intel-Core-i7-8700K-Processor-12M-Cache-up-to-4_70-GHz

You probably know all this, but I'll say it just in case. "Turbo Boost" is basically Intel temporarily overclocking your CPU. When Turbo Boost kicks in when the CPU is under load, the motherboard increases the voltage to support the overclock and then ramps it back down to normal when the load stops. Also, not all cores will hit the maximum turbo boost multiplier. Intel deliberately limits this due to thermal concerns. This is the only chart I could find for your CPU. Intel used to publish this information but they're stopped with recent CPUs so I don't know if it's 100% correct but check out the speeds that each core runs at when you've got all 6 loaded at once. Only one hits 4.7, the next 4.6 and so on until the last loaded core tops out at 4.3. It basically matches the screenshot you posted...

> Is that when there are 0 active cores? Also, running MAME and watching the live value of
> "Active Cores" often showed 0 and no more than 1.

Not sure about the "Active Cores" value. Maybe it's fluctuating faster than the display can update and sometimes displays 0 due to a low sampling rate.

You can a "stress test" within the Intel XTU that will load all your CPU cores. I would turn on the thermal throttle display via the wrench icons in the upper-right corner so you can watch for that. If it gets too hot, it will throttle it back.

The Alienware OC "Stage 1" looks like it's setting turbo max to 4.6GHz on all cores equally. OC "Stage 2" is setting turbo max to 4.8GHz on all cores equally.

I don't know what kind of CPU cooler your system has so that might limit your overclocking due to thermal concerns. Also, I don't know how much overclocking headroom your CPU even has. The stock turbo of 4.7GHz is pretty awesome. How much are other people able to overclock the i7-8700K?

I'd be curious to see your bench numbers if you set all cores to 45x using the Intel XTU (I think it's under Manual Tuning -> Core). That way we can compare the coffee lake architecture performance at the same clock speed as my two Haswell chips as well as John IV's i7-6700K skylake CPU. And we can see how much boost you get from 2 more cores on the games that can use them. If you do a bench at 45x on all cores, can you stick the results in a text file and attach it so that I can more easily paste them into a spreadsheet?

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