IA: Turbo Attenuation (MCT)

[PowerPie5000]

I don't suppose anyone knows exactly what "IA: Turbo Attenuation (MCT)" means in HWinfo? It appears under the "Performance Limit Reasons" section of HWinfo and I can't think what could be causing it to flag up on my i7 6850k... Everything appears to be running ok as far as I can tell and it's running stock with it's default turbo (up to 4GHz).

Does anyone have any ideas? Cheers

[DanceswithUnix]

Was interested enough for a quick Google, only hit was this comment that using XMP enabled MCT (multi core turbo) which seems to lock the core speeds. Your system spec says you have some rather quick ram so I presume that is where it comes from. Sorry that isn't a good answer but might point you in the right direction.

https://www.kitguru.net/components/c...-cpu-review/3/

[ik9000]

could it stand for turbo attenuation on multi-core threads? Not uncommon for BIOS to limit turbo states on overclocked CPUs. Mine won't let me use the turbo boost and speed stepping if I switch it to manual/XMP settings.

[PowerPie5000]

Thanks for the replies. It's still the same no matter what RAM speed I run at (with or without XMP)… I even tried at stock DDR4 2133 timings and it's the same. The CPU isn't overclocked, but running the RAM at DDR4 3000 (XMP) causes the ring bus/uncore speed to jump from 2.8GHz up to 3.1GHz in the BIOS and the RAM voltage to increase from 1.2v to 1.35v.


For some reason the CPU fails the Intel Diagnostic Tool test when I enable the DDR4 3000 XMP profile (fails on AVX instruction tests).

[ik9000]

xmp can be ok up to a point but I tend to find when it gets outside of the native chip set speed ie beyond the official speed and into the "supported by mobo OC" speed that it can be power hungry more than it needs to if you manually oc the board. my rig would burn out if I left it to xmp settings to get it to 2133. it jumps to silly combinations of clock and multiplier that just need too high vcore etc. not wise.