Thoughts on CPU Core ulocking

[Chris_nz]

Hi im an owner of a fx8120. i wanna know what you guys think of unlocking and disabling cores, ive done it before with this core, and i ahcieve 5.4ghz stable. but noticed some impacted on certain games where the frames drop out like crazy.

do you ugys think there are benefits to core disabling especially on these fx chips?

also i dont do any video editing, i do some 3d rendering, am i at a loss in disabling?

cheers

Chris_nz

[King Nothing]

There are tow reasons for locking cores.

1. Defective cores

2. Production and sales

Ive unlocked some Phenom II chips with very diverse results. The best way after unlocking a core is to stress test atleast overnight to see if it is mostly stable THEN start overclocking. Most video editing will like the multi cores but if its defective I wouldnt chance it and just leave that core off.

[Chris_nz]

what about for power saving? you think disabling cores is one way to achieve this? like i said in my post i achieved a higheoverclock with less cores

[allthatremains94]

what about for power saving? you think disabling cores is one way to achieve this? like i said in my post i achieved a higheoverclock with less cores

Yes, disabling cores will save you power, albeit not much.

[Andriko]

What? I thought the FX 8120 already has 8 logical cores, how could you possibly unlock more if there are no more on the die. Are you referring to the message at the beginning when you start up your computer on an AMD pc, says "press to unlock cores"? That was initially for the old athlon x3 or whatever where it had 4 physical cores but one was disabled. This won't work on processors where all the cores are enabled (but it will say it was successful).

Onto the topic of disabling cores. A very few people would want to disable cores because well, there's a reason higher core count processors usually perform better, more multitasking because of the extra amount of data it can process at one time. Disabling cores will help achieve higher clocks on other cores because the power delivery system will have an easier time, and there is less heat from the disabled cores because they aren't drawing power. Games don't necessarily use cores, but if you disable your GOOD cores(remember, some cores may perform better than others, or may just be completely deffective, this is why some cores are disabled on the FX 4000 and the old Athlon x3s through the binning process) then you will see a decrease in fps obviously, so check which cores perform better than others before disabling. I would advise to keep as little as 4 cores on a 6-8 core chip and as little as 3 on a 4 core, or maybe just 2 for gaming, don't even try single cores, no amount of overclocking will help you there.

[Chris_nz]

yes there 8 but in the bios its locked, so you unlockit and disable some of those 8 cores

[TechFan@ic]

Did you do the "disable one core per module" trick ? how did that work out for you ?

Because I'm looking into getting myself an FX 8320 and doing just that.

And what games did you experience crazy frame rate drops in ? because it could be due to GPU drivers or something else.

[Chris_nz]

I notice my Games Speed up when i overclock it over 4ghz, i thought it was my Gpu's but its the cpu. also get alot of frame skips in League of legends. its hard to get a stable clock on the 8120 when i get over 4ghz, ive had it up to 5ghz stable once, but then all my games frame skip alot making them unplayable.

and no i havent heard of the one core per module trick? got a link to it?? or more infomation?

[TechFan@ic]

Oh sure thing mate, here is the link Neither really, http://12tronics.com/index.php?/topic/397-amd-fx-8150-overclocking/

This trick has cought some serious traction lately, everyone that has tried claim that they have noticed lower power consumption, lower temperatures, better instructions per clock and even better clocks on the same voltages when all cores are enabled.

Please try it out and tell me what you think !

[TechFan@ic]

Here is a performance comparison , check the first two benchmarks a 4 core 4 module FX chip is actually faster than the same chip with all 8 cores enabled.

http://www.extremetech.com/computing/138394-amds-fx-8350-analyzed-does-piledriver-deliver-where-bulldozer-fell-short/2

[aicom]

Due to the shared front-end and cache, the Bulldozer integer cores can sometimes be starved for data, due to insufficient decode bandwidth, cache thrashing, etc. Disabling one core per module does eliminate these bottlenecks, but you will only see a gain in tasks that won't stress more than 4 cores. Once you exceed that, just like Intel's HyperThreading, the extra cores come in handy.

[TechFan@ic]

Due to the shared front-end and cache' date=' the Bulldozer integer cores can sometimes be starved for data, due to insufficient decode bandwidth, cache thrashing, etc. Disabling one core per module does eliminate these bottlenecks, but you will only see a gain in tasks that won't stress more than 4 cores. Once you exceed that, just like Intel's HyperThreading, the extra cores come in handy.[/quote']

Yes exactly, that's why I only recommend this for gaming, since games tend to use 2 to 4 cores at most.

[kght22]

i love you guys. this is exactly what was so disappointing about the bulldozer and piledriver chips. they were acting like things were cores when they were crippled by shared cache. they do perform better than hyperthreading, but an 8 core amd proc is essentially a 4 core cpu (by cache) proc that allows 2 threads per core. i hope that this week they introduce something awesome that solves this issue, like a TRUE 8 core processor that has cache for each core, and maybe uses their core doubling trick, so that it acts like a 16 core proc. THAT would be awesome.

EDIT: that is not what i quoted, i think i can add the right quote;

Originally posted by aicom

Due to the shared front-end and cache, the Bulldozer integer cores can sometimes be starved for data, due to insufficient decode bandwidth, cache thrashing, etc. Disabling one core per module does eliminate these bottlenecks, but you will only see a gain in tasks that won't stress more than 4 cores. Once you exceed that, just like Intel's HyperThreading, the extra cores come in handy.

by techfan@tic

Yes exactly, that's why I only recommend this for gaming, since games tend to use 2 to 4 cores at most.

[Fordox]

its just a marketing trick. its a 4 core with hardware like hyperthreading.

we can wait a while for pure 8-cores, since they will go above the 125W TDP. and amd and intel wont want to do that, because of the compatibility with other coolers.

Yes you can disable the cores and it saves on your energie bill but you do get a performance loss.

Have you tried the windows FX fixes yet? those fixes wont improve much but it is something.

http://www.anandtech.com/show/5448/the-bulldozer-scheduling-patch-tested

http://forums.pureoverclock.com/operating-systems/17990-windows-hot-fix-amd-fx-cpus.html

[TechFan@ic]

its just a marketing trick. its a 4 core with hardware like hyperthreading.

we can wait a while for pure 8-cores, since they will go above the 125W TDP. and amd and intel wont want to do that, because of the compatibility with other coolers.

Yes you can disable the cores and it saves on your energie bill but you do get a performance loss.

Have you tried the windows FX fixes yet? those fixes wont improve much but it is something.

http://www.anandtech.com/show/5448/the-bulldozer-scheduling-patch-tested

http://forums.pureoverclock.com/operating-systems/17990-windows-hot-fix-amd-fx-cpus.html

The performance loss is only in applications that utilize those 8 cores ( high threaded work loads), gaming is usually a signle and sometimes lightly threaded (requires 2 to 4 cores) work load.

You gain up to 25% more performance by locking one core per module in single threaded and lightly threaded work loads, it has been tested and confirmed.

Not only that, the power usage drops, along with the heat and the voltage requirement, which allows for even better overclocks which results in even more performance.

Try it, it really works.

[TechFan@ic]

And it's not like you're permanently locking the cores, whenever you intend to do heavily threaded work, just enable the 4 cores back on and crunch those numbers away !

[Fordox]

its just a marketing trick. its a 4 core with hardware like hyperthreading.

we can wait a while for pure 8-cores, since they will go above the 125W TDP. and amd and intel wont want to do that, because of the compatibility with other coolers.

Yes you can disable the cores and it saves on your energie bill but you do get a performance loss.

Have you tried the windows FX fixes yet? those fixes wont improve much but it is something.

http://www.anandtech.com/show/5448/the-bulldozer-scheduling-patch-tested

http://forums.pureoverclock.com/operating-systems/17990-windows-hot-fix-amd-fx-cpus.html

hm maybe nice to read up in it, thanks for the tip.