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Do you keep all L3 memory cache when disabling cores?

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#1
Since L3 memory cache is shared between all the cores in most modern processors, you would think that disabling two cores from a CPU like Core i7 8700K would still leave it's 4 remaining cores sharing that 12 MB L3 memory? Yes?
 
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#2
If the cache is shared, then it's not tied to the cores, is it?
 
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#3
My initial reaction is to say, of course.... however, try it and check CPU-Z for a definitive answer.
 
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#4
L3 cache is shared. Not much point in disabling cores , the CPU will end up prefetching pretty much the same instructions/data regardless given the same workload.
 
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#5
Your question would apply to Theadripper more than the other CPUs.
 

newtekie1

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#6
The amount of L3 stays the same when disabling cores, the amount of L1 and L2 changes.

disabledcores.png
 
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#7
Yes, the L3 cache is shared (flexible is actually a better word for it). It's shared across all the package, which means that not only the execution cores can access it, but also the rest of the blocks of the chip (such as the System Agent or the Integrated GPU). This makes it that if you disable a certain amount of cores, the size of the L3 cache will remain the same.
 
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