Hyperthreading questions

[littlepigboy5]

Just wondering how performance changes from a real core to a virtual core.  granted i don't know exactley  how a processor works, but I know enough to understand them.  An example would be a 4790k vs a 5960x(4790k hyperthreading on, 5960x hyperthreading off).

Thanks

[Pugs501]

[littlepigboy5]

my first idea was to look at a fast as possible lol.  I didn't really get the difference between the two types of cores in performance though.

[themaniac]

well hypertheaded core/logical cores are weaker then full cores/physical cores so the 5960x with hyperthreading disabled will beat the i7 4790k with hyperthreading enabled

[don_svetlio]

A HT is about 20% of an actual core in terms of overall gains - expect 20% increase in multithreaded apps compared to an i5.

[littlepigboy5]

well hypertheaded core/logical cores are weaker then full cores/physical cores so the 5960x with hyperthreading disabled will beat the i7 4790k with hyperthreading enabled

I thought they'd be weaker, but how much weaker

[themaniac]

I thought they'd be weaker, but how much weaker

i'm not entirely sure but i'd guess probably half as strong to 75% as strong

[don_svetlio]

i'm not entirely sure but i'd guess probably half as strong to 75% as strong

A hyper thread is as strong as 20% of the core it's attached to.

[don_svetlio]

I thought they'd be weaker, but how much weaker

20% of the original core

[i_build_nanosuits]

A hyper thread is as strong as 20% of the core it's attached to.

 

20% of the original core

no, that's bullshit, check multi-threaded benchmarks and realise it's anywhere from 25 to 40% depending on the situation...

[don_svetlio]

 

no, that's bullshit, check multi-threaded benchmarks and realise it's anywhere from 25 to 40% depending on the situation...

I'm quoting Linus himself when I say 20%. Can't remember the exact video but I think a WAN show a  year ago had this

[themaniac]

A hyper thread is as strong as 20% of the core it's attached to.

if thats the case then i'd think the 860k would out perform the i3 when both are using all cores/threads then wouldn't you also think so?

[don_svetlio]

if thats the case then i'd think the 860k would out perform the i3 when both are using all cores/threads then wouldn't you also think so?

Nope - the i3 still has stronger single cores.

[i_build_nanosuits]

I'm quoting Linus himself when I say 20%. Can't remember the exact video but I think a WAN show a  year ago had this

no it's a lot more than that in adobe premiere rendering for example hyper-threading i've found cut my rendering times by around 40%...encoding and transcoding also shave a good 40%...compression and encryption usualy around 30%. Anything that can leverage an 8 thread computing workload will see great benefit from hyper-threading and it will be more than 20% boost in the end result...maybe for gaming and shit that is not well parallelised it will be down to 20%, but for good proper workstation related multi-threaded compute loads, it's a lot more than that!

[themaniac]

Nope - the i3 still has stronger single cores.

yeah but i wouldn't think amd's strongest cores are so weak that it takes basically 2 of intel cores to beat 4 of amds cores

[don_svetlio]

yeah but i wouldn't think amd's strongest cores are so weak that it takes basically 2 of intel cores to beat 4 of amds cores

i3s are relatively high clocked at 3.7+ GHz - it's not something to sniff at. Hyperthreading helps but it's not magic. 860K doesn't have trouble matching an i3 - the main reason people pick i3s and 860ks over the Pentium which go even higher is that they handle 4 threads and stutter a LOT less.

[i_build_nanosuits]

yeah but i wouldn't think amd's strongest cores are so weak that it takes basically 2 of intel cores to beat 4 of amds cores

that's because what AMD call a core is in fact half a core...those APU and CPU all based on piledriver, steamroller etc. they all share the same design which is modular design including only ONE FPU and ONE instruction decoder PER two integer units (so...AMD consider an integer unit as a core)

[themaniac]

i3s are relatively high clocked at 3.7+ GHz - it's not something to sniff at. Hyperthreading helps but it's not magic. 860K doesn't have trouble matching an i3 - the main reason people pick i3s and 860ks over the Pentium which go even higher is that they handle 4 threads and stutter a LOT less.

well not all i3's go that high(at least not skylake i3's) but still i wouldn't think it takes basically half the amount of intel cores to beat amd cores

[don_svetlio]

that's because what AMD call a core is in fact half a core...those APU and CPU all based on piledriver, steamroller etc. they all share the same design which is modular design including only ONE FPU and ONE instruction decoder PER two integer units (so...AMD consider an integer unit as a core)

860K is Kaveri - different beast.

 

well not all i3's go that high(at least not skylake i3's) but still i wouldn't think it takes basically half the amount of intel cores to beat amd cores

It takes intel more than half a core - if i3 didn't have HT it'd be getting kicked in the teeth like the Pentium - 20% is still 20%.(for games)

[i_build_nanosuits]

860K is Kaveri - different beast.

no, it's still steamroller architecture it's the same shit it's CMT.

Last true full cores from AMD where Phenom...since then if you want a true AMD quad-core you have to look for one of those ''octocores'' like the FX-8350 for example...this has 4FPU and 4 decoders it's a fancy quad-core with cluster based multi-threading.