PC Power Management Guide

[charge-n-go]

Originally Posted by Chai

Actually, I agree with most of your info except this.

"EIST -
manages processor P-state in the C0 state only."

Are you sure it's C0 state, not C1 state? Because everything you said is right, except that, from my experience anyway. I mean, I see no purpose in having EIST when it's in C0 state. While would you want to throttle the CPU when there's CPU usage?

That is the sole purpose of P-state (Performance State). It manages the processor to give the best performance per watt. A simple question for you: do you want to use Microsoft Word at 65W or 25W if the performance difference is negligible? This is how P-state manage the power according to the CPU load. However, since the transition from one P-state to another is within nano seconds, and the fastest detection tools we have can only report at probably 250 micro second range. So you won't see the changes until it is stabilized at the lowest / highest CPU clock speed for some time.

And yes, i am very sure EIST = P-state power management. It is called Geyserville technology in Intel.

In C1, the processor executes nothing. The execution unit is completed stalled as mentioned in guide. So there is no point to through every level of P-state. It will go straight into the lowest P-state which gives u 6x ratio. The purpose of using lowest P-state in C1, C2 and etc. was already mentioned in the guide too.

If you have any doubts. please read the ACPI specification. It mentioned clearly that P-state power management resides in C0 state.

[Chai]

I also noticed a significant power usage drop at idle compare to EIST disabled.

I guess I can forget what ever I'm going to do now. Haha. Thanks for your info.

[charge-n-go]

Originally Posted by Chai

I also noticed a significant power usage drop at idle compare to EIST disabled.

I guess I can forget what ever I'm going to do now. Haha. Thanks for your info.

Welcome dude

Yea, because C1 is sleep state, the whole core is put down into HALT mode. C0 is active, so even the processor runs at lowest clock speed, there are still millions of transistor working. C1 actually runs at highest clock speed, but C1E brings it down to lowest clock speed. This is more logical lo.

anyway, if u still have doubts, can post here or IM me directly @ YM ! cyeeyong

[Chai]

But the thing is C1E wasn't enabled. And when it's enabled, the voltage dropped to 1.1V. I'm sure without EIST, the C1 state will always be active.

[charge-n-go]

Originally Posted by Chai

But the thing is C1E wasn't enabled. And when it's enabled, the voltage dropped to 1.1V. I'm sure without EIST, the C1 state will always be active.

Yes you are right. C1 is an automated mechanism. The 'E' behind is just a new feature to enable the clock and voltage throttling before C1 kicks in.

[graysky]

Originally Posted by charge-n-go

Yes you are right. C1 is an automated mechanism. The 'E' behind is just a new feature to enable the clock and voltage throttling before C1 kicks in.

Is there an application that can display the current C or P state of the chip? I have noticed that coretemp ALWAYS show C0 state for my chip even when speedstep kicks in...

[firefly]

Originally Posted by The_YongGrand

Hey charge-and-go,

I happened to have the new Celeron 420 - the heatsink is really small, and it's just as cool as cucumber. The heat output - is absolutely minimal!! I touched the heatsink and it's just a little warm.

I don't have any measuring devices for wattage levels of CPU, but I'm pretty sure that it's really 35W...

Hi YongGrand and charge-and-go,

Been reading this forum and the 2 of you really sounded like a "sifu" to me, so .. was wondering .. whether I can get some advice from you guys ...

Was thinking to get a Celeron 420 too .. coz am going to put it in my room and was thinking of on it 24x7 .. for BT downloading ...

So, I was wondering .. will I get any problem if I were to on the PC 24x7? Will it ever get over-heated? Do I need to get any lightning arrester to protect my PC and modem? If so, can recommend any good one?

Also, I wish to run Vista Home Premium. Is there any additional hardware requirement to run Windows Aero?

Lastly, is this Celeron 420 fast enough for day to day use? What would be the ideal RAM for it? Care to advise?

Thanking you guys in advance ... and keep up the good work by sharing more knowledge and information ...

[The_YongGrand]

Originally Posted by firefly

Hi YongGrand and charge-and-go,

Been reading this forum and the 2 of you really sounded like a "sifu" to me, so .. was wondering .. whether I can get some advice from you guys ...

Was thinking to get a Celeron 420 too .. coz am going to put it in my room and was thinking of on it 24x7 .. for BT downloading ...

So, I was wondering .. will I get any problem if I were to on the PC 24x7? Will it ever get over-heated? Do I need to get any lightning arrester to protect my PC and modem? If so, can recommend any good one?

Also, I wish to run Vista Home Premium. Is there any additional hardware requirement to run Windows Aero?

Lastly, is this Celeron 420 fast enough for day to day use? What would be the ideal RAM for it? Care to advise?

Thanking you guys in advance ... and keep up the good work by sharing more knowledge and information ...

Hello and welcome!

Well the Celeron 420 (note the absence of D - it's for the older Cedar Mill and Prescott cores only) is quite a good buy if it's much cheaper! Yes the Celeron 420 is a very ideal one for HTPC and BT rig since it involves only a mere 35Ws. If you don't believe it - the heatsink of Celeron 4xx series are 1/2 of the size of the original stock 775 heatsink. But the thing is, the price of AMD X2 3600+ (not sure whether it is still sold!) looks tempting enough for you to buy that one instead of the Celeron 420. And the Athlons are also equipped with Cool and Quiet, so the throttling of speed will be even less than 35W for the Athlons. The Single-core Athlons are equipped with the same feature too, and it'll not be a worry for you since the performance of both 1-core Athlons64 and Celeron 4xx are almost the same.

The performance of Celeron 420 is comparable to Pentium 4 531 - I tested it. So it'll be a small outline of which one should it be belong to. Too bad it doesn't have a Speedstep, only C1E is supported. If speedstep is available, the Celeron 420 could have reach even lower wattages! Maybe it'll fall a little bit behind in terms of multitasks because the absence of HT.

For the Aero interface, a newer Intel GMA should work (I think it's the 9000 series!) or any cards equivalent or better than Geforce FX5200, which is the minimum one.

Hope that helps!

For the lightning arrestor - try the Cal-Lab. For the PC - you might need a UPS or a AVR.

[firefly]

Originally Posted by The_YongGrand

Hello and welcome!

Well the Celeron 420 (note the absence of D - it's for the older Cedar Mill and Prescott cores only) is quite a good buy if it's much cheaper! Yes the Celeron 420 is a very ideal one for HTPC and BT rig since it involves only a mere 35Ws. If you don't believe it - the heatsink of Celeron 4xx series are 1/2 of the size of the original stock 775 heatsink. But the thing is, the price of AMD X2 3600+ (not sure whether it is still sold!) looks tempting enough for you to buy that one instead of the Celeron 420. And the Athlons are also equipped with Cool and Quiet, so the throttling of speed will be even less than 35W for the Athlons. The Single-core Athlons are equipped with the same feature too, and it'll not be a worry for you since the performance of both 1-core Athlons64 and Celeron 4xx are almost the same.

The performance of Celeron 420 is comparable to Pentium 4 531 - I tested it. So it'll be a small outline of which one should it be belong to. Too bad it doesn't have a Speedstep, only C1E is supported. If speedstep is available, the Celeron 420 could have reach even lower wattages! Maybe it'll fall a little bit behind in terms of multitasks because the absence of HT.

For the Aero interface, a newer Intel GMA should work (I think it's the 9000 series!) or any cards equivalent or better than Geforce FX5200, which is the minimum one.

Hope that helps!

For the lightning arrestor - try the Cal-Lab. For the PC - you might need a UPS or a AVR.

Hi YongGrand,

Thank you so much for such a prompt reply and those useful info. Truly appreciate your input ...

Actually, there is this promo between Citibank, HP and TMnet .. and HP is giving this Compaq Presario SR5122CF CTO Desktop PC for the RM99 per month package.

Below is the full spec of this PC.


Model Number SR5120CF
Product Number GN672AA
Sku Status
Microprocessor Intel® Celeron® processor 420
1.6GHz, 512KB L2 Cache, EM64T, Execute Disable Bit, 800Mhz FSB
Processor Bus Speed 800MHz
Cache 512KB Advanced Transfer Cache
Chipset Intel® 945GC Express Chipset
Memory 512MB DDR2
Expandability expandable up to 2.0 GB with discard
Memory Speed PC2-4200 / 533MHz
Total Memory Slots 2 DIMM
Available Memory Slots 1 DIMM
Audio Integrated Intel High Definition Audio, 5.1 Surround Sound Ready
Hard Drive 80.0 GB * Serial ATA hard drive at 7200RPM *Gigabyte(GB) is defined as 1 billion bytes
Optical Drive 1 CD-RW/DVD Combo Drive (48x32x48x16x)
CD: 48x write; 32x-rewrite; 48x read max speed
DVD: 16x read max speed
Optical Drive 2 None
Video Graphics Intel® GMA 950 Graphics
Video Memory Up to 64MB shared memory
Communication None
Wireless LAN None
Tv Tuner None
Remote Control Module None
Networking Integrated 10/100 BaseT network interface (Broadband Ready)
Digital Media Reader None
Front Access None
Rear Access 2 USB 2.0, 2 PS/2, Line-in, Line-out, Mic-in, LAN
Keyboard Compaq Multimedia Easy Access Internet Keyboard
Mouse Compaq Optical, 2-button PS2 scroller mouse
Total Expansion Slots 1 PCI Express (x16), 1 PCI Express (x1), 2 PCI
Available Slots 1 PCI Express (x16), 1 PCI Express (x1), 2 PCI
Total Drive Bays External (2) 5.25", (2) 3.5"; Internal (2) 3.5"
Available Bays External (1) 5.25", (2) 3.5";
Service And Support 1 year (onsite) limited warranty with up-and-running phone support for first 30 days
LOGO
Vista Logo Free DOS Operating System
Platform brand (Intel Viiv or AMD Live) None
OS & SOFTWARE None
Operating System None
Productivity & Finance None
None
Encyclopedia None
Home Entertainment None
Entertainment None
None
None
Games None
Media Burning & Video Editing Software None
Digital Photography None
Video Editing Software None
Video Editing Software None
Internet & online None
Anti-Virus Software None
PC Help & Recovery PC Doctor
PC Help & Recovery None
PC Help & Recovery None
PC Help & Recovery None
PC Help & Recovery None


Umm .. what do you think about this spec? Any good?

Honestly, I am OK with it .. except the casing doesn't come with a front panel, i.e. I won't have any USB ports in front of the PC. Gosh .. this will be so inconvenient for me .. coz my room is small .. and the CPU is planned to be hidden underneth my table. Imagine I will need to take the CPU out each time I need to use the USB port at the back. Oh boy .. it's not going to be pleasant!!!

Don't know why HP is so cheapskate to remove the front panel. My friend got his HP PC through the TMnet promo in June .. and his model comes with a front panel ...

So, I was wondering .. is there a way to add the front panel later .. through DIY? I understand the front panel comes with the casing .. hmm .. do they sell separately on this? Is it difficult to install? Care to advise?

Also, was thinking to install Windows Vista Home Premium on this PC. Do you think this will be a wise move? Or, I shall stick with Windows XP Pro SP2. Hmm .. but kinda bored with XP and wish to experience the new Vista. But .. heard a lot of bad things about it wor ... ummm ...

[Chai]

Maybe you should create a new thread. This is about PC Power Management.