Battery Life

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07-30-2003, 12:09 AM
jagojago12

Battery Life

Does anyone know how much does an extra stick of RAM affect battery life?

JEDEC specifies that PC133 SDRAM to operate at a DC voltage of 3.3V.
Although I have not done strict lab-environment testing between the before & after of having 2 sticks of RAM, I have felt a noticeable decrease in my battery life. My laptop initially came with 1 stick of RAM. I don't know if there really was a difference in battery life, or if it was just my "psychology" getting the best of me, meaning I only percieved my battery life to drop.

My PCGA-BP2E laptop battery has a voltage of 11.1V @ 3.4 AmpHours for 37.74 WattHours.

I have seen charts on webpages for power consumption in the past and it shows that having multiple sticks of RAM to increase in power usage, but I don't know how accurate those figures are. 2 128MB sticks of DDR at 2.50 Volts can use upto 30 Watts of power? Link: http://www6.tomshardware.com/howto/2...pplies-02.html

I have 2 sticks of 256MB PC133. Would having 1 stick of 512MB PC133 offer less power consumption than 2 sticks of RAM but of equal total capacity, and would it offer the same power consumption as 1 stick of 256MB?
08-08-2003, 04:43 PM
ace727861986

Re: Battery Life

Quote:

Originally posted by jagojago12
Does anyone know how much does an extra stick of RAM affect battery life?

JEDEC specifies that PC133 SDRAM to operate at a DC voltage of 3.3V.
Although I have not done strict lab-environment testing between the before & after of having 2 sticks of RAM, I have felt a noticeable decrease in my battery life. My laptop initially came with 1 stick of RAM. I don't know if there really was a difference in battery life, or if it was just my "psychology" getting the best of me, meaning I only percieved my battery life to drop.

My PCGA-BP2E laptop battery has a voltage of 11.1V @ 3.4 AmpHours for 37.74 WattHours.

I have seen charts on webpages for power consumption in the past and it shows that having multiple sticks of RAM to increase in power usage, but I don't know how accurate those figures are. 2 128MB sticks of DDR at 2.50 Volts can use upto 30 Watts of power? Link: http://www6.tomshardware.com/howto/2...pplies-02.html

I have 2 sticks of 256MB PC133. Would having 1 stick of 512MB PC133 offer less power consumption than 2 sticks of RAM but of equal total capacity, and would it offer the same power consumption as 1 stick of 256MB?

I asked my dad about this and he said sure it would use more power. The more stuff to run electricity threw will cause more of a power drain.
08-08-2003, 05:22 PM
ThAz

I have 2 sticks of 256MB PC133. Would having 1 stick of 512MB PC133 offer less power consumption than 2 sticks of RAM but of equal total capacity, and would it offer the same power consumption as 1 stick of 256MB?

It depends, if the 256MB sticks are singlesided it will not have any difference, but if they are doubblesided you will have 1/2 the ammount of memory modules if you go with one 512MB stick.
08-08-2003, 07:20 PM
jagojago12

Quote:

Originally posted by ThAz
It depends, if the 256MB sticks are singlesided it will not have any difference, but if they are doubblesided you will have 1/2 the ammount of memory modules if you go with one 512MB stick.

Let's assume that's the case. You have 2 256MB double sided sticks. Then you upgraded to a single 512MB double sided stick.

You are saying power consumption of a single double sided 512MB stick = power consumption of a single 256MB double sided stick? I'm thinking maybe the 512MB stick will require more power, maybe because the chips themselves are higher density. Thus, requiring more amperage and increasing the total wattage requirement.
08-08-2003, 07:26 PM
jagojago12

Re: Re: Battery Life

Quote:

Originally posted by ace727861986
I asked my dad about this and he said sure it would use more power. The more stuff to run electricity threw will cause more of a power drain.

There was little doubt in my mind that 2 sticks required more power, but as to how much, I wasn't sure. I would really be comforted if I knew how much my wattage use increased from adding an additional 256MB stick. I really don't believe Tom Hardware's Guide is accurate regarding laptop SODIMM memory. I mean 30 Watts for two (2) 2.50 Volt RAM sticks is even more power than what my 1.13GHz processor requires; that's crazy. My Battery only supports 37.74 WattHours anyway. I know I can use over 37.74 Watts, but that will shorten battery life drastically.

If it only decreased my battery life by 5 minutes, I can live with that. However, if it decreased my battery life on the order of 20 minutes, I might actually downgrade my laptop for trips.

I think I'm probably the only one that can determine this with 100% accuracy, but I was just curious if anyone knew since I would rather not take out the sticks and do benchmark testing :(.
08-09-2003, 08:27 PM
ThAz

Quote:

Originally posted by jagojago12

Let's assume that's the case. You have 2 256MB double sided sticks. Then you upgraded to a single 512MB double sided stick.

You are saying power consumption of a single double sided 512MB stick = power consumption of a single 256MB double sided stick? I'm thinking maybe the 512MB stick will require more power, maybe because the chips themselves are higher density. Thus, requiring more amperage and increasing the total wattage requirement.

You got me there, i didn´t think of that

Well if you think about it logicly they have more transistors than smaller memorymodules so they must consume more power, but i would think that there should be atleast a little power saving to have 1 512MB stick.
08-10-2003, 07:12 AM
jagojago12

Quote:

Originally posted by ThAz
You got me there, i didn´t think of that

Well if you think about it logicly they have more transistors than smaller memorymodules so they must consume more power, but i would think that there should be atleast a little power saving to have 1 512MB stick.

Yeah. I don't know if the additional # of transistors on the single 512MB stick would outweigh the power usage of fewer transistors per 256MB stick (thus lower power consumption on a stick-by-stick basis) but having 2 256MB sticks instead of 1 512MB stick.

If I were to place by bets though, I think the 512MB stick should use less power because I think there's some inefficiency or overhead from having 2 physical sticks of RAM instead of 1 in terms of delivering to powering them.
08-10-2003, 09:14 AM
ThAz

I found something interesting for you :

McCarty, Paul" wrote:
>
> > -----Original Message-----
> > From: Christopher Allen [mailto:]
> >
> > On Thu, 14 Nov 2002, McCarty, Paul wrote:
> > > 512MB PC133 SoDimm $60 ($0.11/MB) [1-2 watts]
> > ^^^
>
> I have 2 SoDimms here. One PNY PC133 128MB, and one unmarked PC100
> 256MB. These are standard notebook SoDimm modules. I have measured power
> consumption of an embedded windows system with video controller, etc.
> And typically the power consumption is around 4 watts. Not very
> scientific, but I know the minimum power consumption of the components
> of this system other then memory is 3 watts leaving 1 watt for memory. I
> also noticed the 128MB versus 256MB made no difference in power
> consumption. I'm chalking it up to smaller feature sizes on higher
> density chips.
> If I could fit a small resistor between the SoDimm socket and the
> motherboard, maybe I could get better numbers.
>
> As for price, I must have made a mistake. I did a second search for
> cheap SoDimms and found a minimum price of $71 from www.Digi4me.com.
>
> I did buy the 128MB for $15 from CircuitCity. so 4x$15=$60. Sorry about
> that.
>
> -Paul

http://www.eyetap.org/wearable/wear-.../20028705.html
08-10-2003, 10:01 AM
jagojago12

Quote:

Originally posted by ThAz
I found something interesting for you :

McCarty, Paul" wrote:
>
> > -----Original Message-----
> > From: Christopher Allen [mailto:]
> >
> > On Thu, 14 Nov 2002, McCarty, Paul wrote:
> > > 512MB PC133 SoDimm $60 ($0.11/MB) [1-2 watts]
> > ^^^
>
> I have 2 SoDimms here. One PNY PC133 128MB, and one unmarked PC100
> 256MB. These are standard notebook SoDimm modules. I have measured power
> consumption of an embedded windows system with video controller, etc.
> And typically the power consumption is around 4 watts. Not very
> scientific, but I know the minimum power consumption of the components
> of this system other then memory is 3 watts leaving 1 watt for memory. I
> also noticed the 128MB versus 256MB made no difference in power
> consumption. I'm chalking it up to smaller feature sizes on higher
> density chips.
> If I could fit a small resistor between the SoDimm socket and the
> motherboard, maybe I could get better numbers.
>
> As for price, I must have made a mistake. I did a second search for
> cheap SoDimms and found a minimum price of $71 from www.Digi4me.com.
>
> I did buy the 128MB for $15 from CircuitCity. so 4x$15=$60. Sorry about
> that.
>
> -Paul

http://www.eyetap.org/wearable/wear-.../20028705.html

Very interesting. I knew something was fishy when I visited this link http://www6.tomshardware.com/howto/2...pplies-02.html that said 2 sticks of 2.50 Volt DDR SDRAM being a whopping 30 Watts :eek:. When I looked at that I thought to myself "Since my PC133 is older technology, and also runs at a higher voltage, it might even use more power," so I started to worry a bit. Maybe the 30 Watt figure for desktop DDR SDRAM is still right, but I'm glad that isn't the case with SODIMMs.

From the looks of it, it seems like SODIMMs don't take very much power additional power per additional stick, at least for that guy. I think having 2 sticks does use more power, which is a given, but now I know it's probably a negligible difference.

I feel better about having 2 sticks of RAM in my laptop now. Thanks for helping out my conscience :).