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post #181 of 369
@Forceman

If the CPI doesn't spend a lot of time at 100MHz, then what is its purpose?
post #182 of 369
Sorry, not sure what you mean.
post #183 of 369
Quote:
Originally Posted by Forceman View Post

Sorry, not sure what you mean.

Argh, sorry I was mobile when I posted that. I meant this:

If the CPU doesn't spend a lot of time at 1600MHz, then what is its purpose?
post #184 of 369
I don't know, but that's why I think there is still benefit in setting the CPU up to downclocking, and to use a offset voltage. If those things didn't provide some purpose then Intel wouldn't have designed the chip to work that way. If it is just as power efficient (or more) to run it full-speed/full-voltage all the time and just use C3/C6 for power control, then why go to all the trouble to develop Turbo Boost, and EIST? Seems like Intel would have known what they are doing there, especially given their focus on power efficiency.
post #185 of 369
Quote:
Originally Posted by Forceman View Post

I don't know, but that's why I think there is still benefit in setting the CPU up to downclocking, and to use a offset voltage. If those things didn't provide some purpose then Intel wouldn't have designed the chip to work that way. If it is just as power efficient (or more) to run it full-speed/full-voltage all the time and just use C3/C6 for power control, then why go to all the trouble to develop Turbo Boost, and EIST? Seems like Intel would have known what they are doing there, especially given their focus on power efficiency.

True. This is also what I think about and I really want unclewebb to help us on this. He might have some insights that we still do not know.
post #186 of 369
When using C6 and EIST, the processor will still down clock when it doesn't have anything to do. The difference is that you can combine C6 with the Windows High Performance profile and you can use a fixed voltage without any negative side effects and you will be able to come up with a stable overclock faster. The Balanced profile that locks the CPU at 1600 MHz isn't necessary when C6 is enabled. The High Performance profile will let the CPU manage itself and it does a great job of that.

The problem is that everyone has been brain washed by CPU-Z. They see their CPU locked at the highest Turbo multiplier when lightly loaded when it really isn't and then come up with various settings to "fix" this problem. Check out the multiplier data coming from RealTemp for a more accurate look at what the CPU is really doing when it is idle or lightly loaded. The other misconception is that running a CPU at 1600 MHz uses less power than running it at say 4000 MHz but that's not true when C6 is enabled.

I don't think it was Intel that dreamed up offset voltages. Motherboard manufacturers came up with this because they know most enthusiasts immediately turn off the C3/C6 low power states. Offset voltages is a cobble job that can lead to BSOD issues if not set up correctly and no matter how you set up your offset voltages, you will always get less power consumption and less heat by simply turning on C6.

When a CPU core is able to spend 99% of its idle time in C6 at practically zero volts, a high or low voltage has no material impact on power consumption because it won't be at that voltage. The CPU core will mostly be at zero.

As mentioned in another forum, these CPUs are capable of running at 800 MHz. Intel likely turned this feature off because slow CPUs are inefficient and don't save any power when the alternative is to run a CPU fast and put it into C6 when it has nothing to do.
Edited by unclewebb - 2/17/13 at 9:06am
post #187 of 369
Quote:
Originally Posted by unclewebb View Post

When using C6 and EIST, the processor will still down clock when it doesn't have anything to do. The difference is that you can combine C6 with the Windows High Performance profile and you can use a fixed voltage without any negative side effects and you will be able to come up with a stable overclock faster. The Balanced profile that locks the CPU at 1600 MHz isn't necessary when C6 is enabled. The High Performance profile will let the CPU manage itself and it does a great job of that.

The problem is that everyone has been brain washed by CPU-Z. They see their CPU locked at the highest Turbo multiplier when lightly loaded when it really isn't and then come up with various settings to "fix" this problem. Check out the multiplier data coming from RealTemp for a more accurate look at what the CPU is really doing when it is idle or lightly loaded. The other misconception is that running a CPU at 1600 MHz uses less power than running it at say 4000 MHz but that's not true when C6 is enabled.

I don't think it was Intel that dreamed up offset voltages. Motherboard manufacturers came up with this because they know most enthusiasts immediately turn off the C3/C6 low power states. Offset voltages is a cobble job that can lead to BSOD issues if not set up correctly and no matter how you set up your offset voltages, you will always get less power consumption and less heat by simply turning on C6.

When a CPU core is able to spend 99% of its idle time in C6 at practically zero volts, a high or low voltage has no material impact on power consumption because it won't be at that voltage. The CPU core will mostly be at zero.

As mentioned in another forum, these CPUs are capable of running at 800 MHz. Intel likely turned this feature off because slow CPUs are inefficient and don't save any power when the alternative is to run a CPU fast and put it into C6 when it has nothing to do.

Yes. Actually we understand what C6 does. Our argument here is why do you recommend fixed voltage + c6 over offset voltage + c6? If one can setup offset voltages properly with c6 enabled without ever getting a BSOD, isn't that better than using a fixed voltage with c6 enabled? And if your target is for the cpu to stay at high clocks (not downclocking to 1600 MHz) then why is your EIST setting enabled as you've mentioned earlier?

What if I'm watching a movie that only needs about 25% CPU power. If downclocking isn't permitted, then my CPU will be at 100% all the time and will never go to C6 state for the rest of the movie. In that way, won't the necessary clock speed (25% - downclocked from 100%) be better in terms of power savings?
post #188 of 369
This is an interesting discussion keep it up! thumb.gif
If it is more beneficial to set Win to Performance profile from Balanced and still keep the power saving benefits I will go and do that!
Although most of the time I use my System for actual use and limited amounts of idle work (browsing). The rest of the time it is in Sleep, so I probably won't notice any differences.
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CPUMotherboardGraphicsRAM
i7 3770k Asus P8Z77-V EVGA GTX780 SC ACX Samsung DDR 3 (2 DIMMS) MV-3V4G3D/US 
Hard DriveHard DriveOptical DriveCooling
Samsung 830 SSD WD Caviar Black Asus DVD/RW Xigmatek s-1283 HDT (Air Cooling) 
CoolingCoolingOSMonitor
Scythe Slipstream 1200RPM (x2) Antec 140mm + Antec 120mm + Xigmatek 120mm (x2) Win 7 64bit Acer S243HL bmii - 24" 
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Corsair TX750 Corsair Carbide 300R MX 518 Auzentek X-Fi Forte 7.1 
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post #189 of 369
The reason I have EIST enabled is because it is impossible to disable it in the bios on my motherboard.

The bios will provide users with a bunch of options so you can enable and disable various CPU features. After you push OK or Save, it looks at your selections and then it ignores some selections that are not compatible with each other. On my Asus P8Z77-V Pro board, I have an option in the bios to enable or disable EIST / SpeedStep but after I boot up, no matter what I choose, I find that EIST has automatically been enabled. I always thought EIST was necessary for the proper functioning of the Turbo Boost feature so perhaps that's why Asus always leaves it on or maybe it is just a bug with my board.

As a user, if I disabled EIST in the bios, I would be believe that EIST was truly disabled. After testing my board, I am thinking that there are probably a lot of users convinced that they have EIST disabled when in fact it is still enabled within the CPU.

If you want to find out what your board does with EIST, disable this in the bios, boot up but don't run any utility programs. Next, run my MSR Tool and read MSR 0x1A0. This is the register in the CPU that will show whether you booted up with EIST enabled or disabled. Changing this register after you have booted up a Core i CPU doesn't seem to change anything.

MSR Tool
http://www.mediafire.com/?myjkxzkzzmd

You just need to enter 0x1A0 in the MSR Number box and then click on the Read MSR button. If bit[16] is set, that means the bios left EIST enabled. Post a screen shot or copy and paste the contents of the EAX register if you need me to interpret your data.

When the C6 core state is enabled and you are watching a movie or working on any task where the CPU is not being 100% utilized, the unused cores will automatically enter the low power C6 state. Here's an example while running a 2M Super Pi bench.

http://img17.imageshack.us/img17/2089/superpicscore.png

One quarter of the CPU is being utilized by the Super PI bench and on average, 73% of the time, the unused cores are in C6 using close to zero power. The rest of the time the CPU is working on various Windows background tasks.

When using C6, I don't see any significant time when offset voltages would ever be used. If the CPU is in the C0 state working on a task, it is going to be at the full turbo multiplier so you need to give it as much voltage as necessary to be stable. When it is not in C0 working on a task, it immediately drops back down to C6 where the fixed voltage you have entered in the bios is ignored.
post #190 of 369
Very enlightening, unclewebb.

Thanks,
Sabre10.
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