lvl1 or lvl2 hardware prefetch in bios or both?

[AMF]

im tryingto figure what is the best setting. can anyone help?

 

[Vya Domus]

Best left untouched.

 

[AMF]

Best left untouched.

REASON? what does it actually do?

 

[izy]

Hardware prefetchers work well in workloads that traverse array and other regular data structures. The hardware prefetcher options are disabled by default and should be disabled when running applications that perform aggressive software prefetching or for workloads with limited cache.

This default setting is "Enabled". In some cases, setting this option to Disabled may improve performance. Users should only disable this option after performing application benchmarking to verify improved performance in their environment.

(source: google)

 

[Vya Domus]

REASON? what does it actually do?

It has to do with the way the processor fetches data into it's cache, the reason it's best to leave it alone is because for one whatever effect it has it's likely imperceptible most of the time and secondly it's so application specific and nuanced that it's not even worth messing with.

I don't know why they even have this option available on consumer hardware, it's something only in a server/datacenter environment you'd even consider changing.

 

[agent_x007]

Disabled get's stability, Enabled get's higher performance per MHz.
You decide what you need :
1) Stability range is between 0 and "I don't know how many more MHz AFAIK no one checked", but you can be first
2) Performance increase is also 0 to "I don't know how many more MHz AFAIK no one checked", but you can be first
Nothing more is needed to know.

 

[izy]

Disabled get's stability, Enabled get's higher performance per MHz.
You decide what you need :
1) Stability range is between 0 and "I don't know how many more MHz AFAIK no one checked", but you can be first
2) Performance increase is also 0 to "I don't know how many more MHz AFAIK no one checked", but you can be first
Nothing more is needed to know.

Is the stability software related ? (depending on what program / game your are using ?)

 

[AMF]

thanx guys yallwere helpful i thought as much about off being more stable

 

[izy]

Got back with some weird analogy , its like counting on your instincts when doing some type of team work , if your team m8s are easy to predict (or you have synergy) you can do the job faster predicting where they will be at some point in time, you are going to be there before you see them going there and you can speed up the work done but if your team is harder to predict you will do the job worse because you will lose time going somewhere where there is no work to be done as your team m8 will be elsewhere (can be from 2x to whatever slower depending on work) , its pure luck in this situation to increase the work done , statistically will be worse, i think is the same situation with prefetch.
Edit: to get back to my own question , my guess is that is depending on the software used. (dont take it as valid , its just my logic).

Edit2: i think my analogy was bad in some way as you have to predict the work not the workers , but the idea is the same , you send people to do the work to a location where you think the work has to be done and if there is no work there you lose time (performance) ... etc.. i could had been more accurate (even this is not that accurate) but i was only trying to explain the logic as i see it on fast forward.