Speedstep and c state on but constant voltage.

[hunkeelin]

If I have c state and speedstep enabled, but I manually set voltage will I be saving electricity bills?

Thanks

 

[Burpo]

Yeap! I save electric bills too.. There's a pile of them on my printer!

 

[Soulkeeper]

The power gating is controlled by the cstate, this accounts for the vast majority of the savings from what i've seen.
I lock my cpu at a certain MHz/voltage with only the cstate stuff enabled and idle power usage is within the margin of error on my kill-a-watt

 

[tortillasoup]

I don't know about your computer but at least with my AMD Fusion based laptop, I can set upper CPU mhz limits on the laptop so that if I need the laptop to be mostly quiet, it can throttle up the CPU when needed but will top off after a certain speed like 2ghz or if I need absolute power savings, it won't go higher than 1400mhz. The max continuous speed is 2400mhz with "boost" up to 3100mhz but it's fake boost as it lasts only a fraction of a second and only if 1 cpu is loaded up, otherwise the max overdrive is like 2700mhz.

 

[flexy]

If I have c state and speedstep enabled, but I manually set voltage will I be saving electricity bills?

Thanks

YES!

See here:

HWInfo shows the actual Vcore on my i7, I also have voltage set to manual. Notice how the actual vcore is very low because of active processor c-states.

 

[Maximilian]

If I have c state and speedstep enabled, but I manually set voltage will I be saving electricity bills?

Thanks

Not really no :|

Electricity here costs ~13p per kwh. My pc uses 60 watts sitting idle, 1000/60 = 16.6666, so it takes 16.6 hours to use 1kwh. Leaving the thing on 24/7 for a 31 day month, costs £5.72

744 hours in a month / 16.6 = 44, so that's 44kwh in a month which at 13p per kwh is 44kwh * 13p = 572 or £5.72

Electricity is peanuts, don't expect any big savings by footering around with voltages. Use the microwave instead of the oven or turn the heating/air con down to see some real benefits.

You may see better CPU temps with a lower voltage but IMO leaving the thing on auto does a good job these days, haswell chips idle as low as 0.8v

 

[hunkeelin]

Ok, it seems c state decreases performance of the cpu though. When I bench with c state disabled I get a score of 18500~18600 in real bench h264. When I have it enabled i get 18000s. Any thoughts?

 

[sm625]

I have my CPU manually set to 1.3V, but it still spends most of its time around 1.08V

 

[tortillasoup]

Ok, it seems c state decreases performance of the cpu though. When I bench with c state disabled I get a score of 18500~18600 in real bench h264. When I have it enabled i get 18000s. Any thoughts?

But that's a small difference... that's like the performance difference I would get when using a benchmark software with Normal Process priority set in task manager vs. "Realtime".