in multi-core CPU configurations?
This is my situation:
I want to save power while maximising performance.
I have a Quad Core, so do you think
A)Four cores at a low clock speed
Or
B)Two cores at a higher clock
Or
C)One core at higher clock than B
Is better?(Exclude power saving features)
2 cores at high speed, unless you have extremely multi-threaded applications in which case four low-speed cores will do the trick.
Switching to one core is akin to shooting yourself in the foot.
Originally posted by Raraken:2 cores at high speed, unless you have extremely multi-threaded applications in which case four low-speed cores will do the trick.
Switching to one core is akin to shooting yourself in the foot.
Roughly what clock speed would you recommend for each situation?
Originally posted by Call4ljw:Roughly what clock speed would you recommend for each situation?
Depends on CPU in question.
You don't need to do anything if you are running Intel hardware, since the chips have power gating and Turbo Boost. AMD chips, on the other hand, need more hands-on experience.
I would suggest undervolting at stock speeds first with all four cores enabled. I have my 955 undervolted to around 1.3V at full load, and I shaved off 15W off my max TDP. Idle remains the same at 20W. I'm too lazy to tweak further, but I'll get around to that soon enough.
Am i right to say that 0.8V x2 vs 1.6V x1 is same power consumption?
Originally posted by Call4ljw:Am i right to say that 0.8V x2 vs 1.6V x1 is same power consumption?
Voltage isn't linear. 0.8V x2 isn't the same as 1.6V x1. Sending 1.6V through your CPU will very likely kill it.
Originally posted by Raraken:Voltage isn't linear. 0.8V x2 isn't the same as 1.6V x1. Sending 1.6V through your CPU will very likely kill it.
Shouldn't it be if the ampere is constant?
Originally posted by Call4ljw:Shouldn't it be if the ampere is constant?
That would imply that one core is consuming the power of two cores.
Less cores at a higher speed is better.
But why do they keep increasing the number of cores?
Up to 8 already, in no time it will go to 10 or even 12.
Off-topic: Intel's oregon team is good.^^
alot of good processor designs come from there.
Originally posted by Call4ljw:Less cores at a higher speed is better.
But why do they keep increasing the number of cores?
Up to 8 already, in no time it will go to 10 or even 12.
Because the industry is shifting to multi-threaded parallel architectures. Lower-clocked but higher core count processors tend to be more efficient than higher-clocked with fewer cores.
There are already 12 core CPUs by AMD for the HPC industry, their Magny-Cours Opterons.
Originally posted by Raraken:Because the industry is shifting to multi-threaded parallel architectures. Lower-clocked but higher core count processors tend to be more efficient than higher-clocked with fewer cores.
There are already 12 core CPUs by AMD for the HPC industry, their Magny-Cours Opterons.
Okay...i still have no direct answer as to whether more cores is better, but i just decided to do according. Because, according to passmark.com, a 1.6Ghz i7 720QM performs almost equivalent to a 32nm core i5 661 Dual core of 3.3Ghz.
And i sort of found out that core-to-core scalability is rougly 80%.
Which some sum up like this: 100%(always 100% for the first core),80%,80%,80%
I did 1.6Ghz Quad-core, which ends up equivalent to 2.93Ghz dual-core.
I dont have a multi-meter, so can't test power consumption.
Originally posted by Call4ljw:Okay...i still have no direct answer as to whether more cores is better, but i just decided to do according. Because, according to passmark.com, a 1.6Ghz i7 720QM performs almost equivalent to a 32nm core i5 661 Dual core of 3.3Ghz.
And i sort of found out that core-to-core scalability is rougly 80%.
Which some sum up like this: 100%(always 100% for the first core),80%,80%,80%
I did 1.6Ghz Quad-core, which ends up equivalent to 2.93Ghz dual-core.
I dont have a multi-meter, so can't test power consumption.
As I indicated on one of my posts above,
it depends on your workload. Are you doing heavy video editing/ 3D modelling or just regular stuff? Are your programs programmed to take advantage of as many cores as possible?
Originally posted by Raraken:As I indicated on one of my posts above,
it depends on your workload. Are you doing heavy video editing/ 3D modelling or just regular stuff? Are your programs programmed to take advantage of as many cores as possible?
A large percentage on gaming, so i disabled HT.
Mostly can take advantage of multiple cores.
Even with underclocking, i feel the power consumption still very big after adding in power of discrete graphics.
I'm thinking of looking to Sandy Bridge's 35W desktop CPU which comes with iGPU.
Though the iGPU = HD5450, but i normally play 2D games like maplestory, so should be fine.
Fine, not find.
Dictionary.com in your spare time, thanks.
in the power formula
P=VI
P=V/Rsquare
see voltage is the numerator and multiplier at the same time. so i gues having Resitence and current as constant an increase in viltage rating generally means it can draw more power to perform heavier applications.
if your PSU has thsufficient power rating, and your PSu has a higher amp rtaing at the targeted railings i guess the only time it will draw more power is how many peripherals youconnect to the comp how heavy your software applications are that demands the hardware performance.
Originally posted by SBS7484P:Fine, not find.
Dictionary.com in your spare time, thanks.
Typo error.