Disabling CPU Prefetch features boosts single thread performance

[RejZoR]

Prefetching enabled:

Prefetching disabled:

5820K has two prefetch settings in BIOS, one is Hardware Prefetch and second, Adjacent Cache-Line Prefetch. I disabled both for lolz just to see how it goes.

Single thread performance was consistently higher by ~50 points where multithreaded hardly ever changed much. 20 is about as much difference I ever got. And that's from 12 threads combined. 50 jump is just for single thread. Only thing that changed between both runs are the cache settings, no fiddling with clocks or other settings.

I just find this interesting...

 

[Toothless]

Soooo not really worth changing a setting?

 

[basco]

i tried on x99 sabertooth and not 1 point moar.
do you have c-states and downclocking on??
if yes try to run a short multithreaded bench(like hwbotprime or wprime) before you push start on bench cpu.
this way i get better scores in both.

 

[RejZoR]

I only have EIST enabled. C-States are off.

 

[arbiter]

looking at the number its only 42 points, which is only 2% boost so i would kinda see that is within margin for error. Turning it off or leaving it along least from those screen's there is detriment or benefit

 

[RejZoR]

It's not margin of error when it consistently goes well over 2000, but with prefetching enabled, it NEVER goes above 2000. Meaning it is a consistently measurable difference, even though small, but there is.

 

[GreiverBlade]

less noticeable on Skylake although multi thread increase of 92pts in that case, where your take a -22pts hit , well that make your 4.5ghz 5820K ipc's going almost up to 4.4ghz 6600K

enabled and disabled

 

[basco]

if you have cstates and eist enabled:

whithout cpuload(hwbotprime) before bench

with cpu load before bench

and for me this bench is very accurate +-5 points margin whithout eist+cstates

 

[jboydgolfer]

curious about whether this might effect my pentium.

i removed some of the prefetch settings on this Chip, and got the following...its obv OC'd

 

[EarthDog]

Well did it???? ^^

You only posted one result and no mention if it helped or not.........

 

[Filip Georgievski]

My i5 750 now has a new ASUS board with both Prefetch settings and i do not see the difference between old MSI P55 without Prefetch and new (second hand) Asus H55 board other than the fact that both MBs are awsome overclockers, pushing my CPU to 4GHZ OC stable at 1.28V and a single-thread score of 1400+ on CPUZ Bench.