I7 975 EXTREME 3 different clock speeds reporting??

Hi all, first post here

So, im not some overclocking pro, but i have dabbled over the years, anyway, ive got an old system with a I7 975 EXTREME which i thought i could have some over clocking fun with, so im currently sitting at 4.1ghz stable, but i have three speeds being reported, CPU-Z says 4.1ghz (27x152) REALTEMP says 4.26ghz (27x158) and in task manager performance it says 3.53ghz...............

Why would this happen?

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Task Manager read 4.8 Ghz when I was at 4.0 Ghz, didn't actually notice that I was running a whooping 5.5 Ghz as of now

My advice would be to trust CPU-Z the most, forget about task manager.

What BUS Speed did you actually set in the BIOS? That seems to account for the difference from realtemp to cpuz.

its set to 152 in bios, and on the post/boot screen it shows 4.1ghz too

Then I'd say CPU-Z reports the clock speeds correctly, as I assumed. As to why the reports / readings differ: no idea

Taskmanager is just probably reporting the factory base frequency.

windows doesnt always correctly read the cpu speed since it is overclocked, i have had this happen on xp/win 7, i dont use win10 at all on my main. i do have a x58 setup i installed win7 on and tried the free update to 10 and same thing, it doesnt read the new cpu speed for me. there could be a reason it doesnt work for me but might for others, thats not something i looked into. as i always suggest going by the bios cpu speed reading as it will also match CPUZ reading.