Does more memory consume more power?

[SteveDC]

I am not an expert on the latest semiconductor technology, but I understand that, in general, more gates means more power consumption through leakage current, etc. So, does my battery life decrease with more memory?

On the other hand, more memory would reduce the amount of disk thrashing that has to go on, maybe offsetting the power consumed by more memory.

Thank you in advance for considering my question.

[GomJabbar]

I believe that having adding RAM to decrease disk-thrashing reduces power consumption. However, I also believe it is possible to reach a point were adding more RAM does not reduce hard drive activity (unless you use a RAM disk), and at this point, adding additional RAM probably would consume more power.

[AlphaKilo470]

Depends. Too little RAM will result in more swap file usage, thus meaning more hard drive usage and athough not in all, in most cases hard drive usage will eat more power than RAM usage.

If the RAM is used significantly more than the hard drive, it is possible that the ram could start using more power than the hard drive but even in that unlikely case, it'd most likely be less power usage than if the swap file was running in place of all that RAM.

There is, however, a theorettical equilibrium point between RAM and hard drive but because the power difference would be vaguely noticable and because that point changes with every kilobyte that's added or subtracted from your drive, it'd be a rather futile effort to find it.

In conclusion, more RAM will ultimately result in better power consumption for most normal to heavy computing use. The only exception to this is when the computer is idle or in standby but the power consumption difference there is so small, it really shouldn't matter at all.

[Aroc]

All the tests I've seen show that battery drain due to large amounts of RAM to only be a few minutes at best, when measured over the course of many hours. This is minicule compared to higher drain devices like you display's backlighting (use the lowest setting comfortable for you), optical drives (rip those CDs and DVDs as ISOs to your hard disk), hard disk, and wireless adapters.

all things being equal, yes more ram does consume more power. But you have to take it in context, like everyone else is saying.

[DIGITALgimpus]

I believe that having adding RAM to decrease disk-thrashing reduces power consumption. However, I also believe it is possible to reach a point were adding more RAM does not reduce hard drive activity (unless you use a RAM disk), and at this point, adding additional RAM probably would consume more power.

Correct.

Until you break about 1-1.5GB (depending on your usage) you'll be saving more Battery life then the RAM will cost you.

[jhonyl]

What I was told (when I asked Micron, if I remember right) is that each RAM module takes a certain amount of power regardless of its size[MB]. So if you have one module it would consume less power than if you have two modules. For example if you have a total of 256MB in two 128MB sticks, it would consume more than if you have one 512MB stick for instance.

It is also true that disk thrashing is power expensive, and that more memory may help to reduce that. However how much memory you need depends on what you do with your computer, and it doesn't necessarily mean that if you use more memory than your physical RAM that you will thrash the disk. I used more memory than I have without any noticable effect. You can know that the disk is thrashing by the sound of it and by the time that it takes the computer to respond, since the disk is much slower than the physical RAM.

Moreover, IBM Preload(ed) Windows OS have prevented my hard disk from spinning down (I.e. stop). I did a fresh install of Windows OS, as described in the Windows OS forum (here), and the problem was solved. I believe that spinning down also save power.

[GomJabbar]

Moreover, IBM Preload(ed) Windows OS have prevented my hard disk from spinning down (I.e. stop). I did a fresh install of Windows OS, as described in the Windows OS forum (here), and the problem was solved. I believe that spinning down also save power.

How did you know that your hard disk was not spinning down? By sound or some other method?

[Esben]

I have max'ed the memory, but my harddrive still blinks every third second. I don't know what's causing it, but my original plan was to use the extra gigabyte as an extra ram-based drive, for all temporary files, allowing the harddrive to spin down and thereby use less power.

Before my purchase, I also speculated whether it would be better going with lesser memory, for less battery use. My brother, an electrical engineer, replied that the power use of memory is miniscule compared to the rest of the system.

[jhonyl]

GomJabbar:

Mostly by the sound of it. It is enough for knowing if your disk operates or not. But I also looked at the 'Administrative tools'->'Performace' which allows you to monitor many things, and I saw there the disk operation as well.

Esben:

Did you fresh install windows? (see my prev. post)

Edit:

PS. My theory about it is that IBM messed up the Hitachi disk driver probably in order that it will park the head ASAP for their disk "Air Bag" application, but the result was that as soon as the disk had no activity it started to park the head, and unpartk it, and park it and unpark it, which sounded like a tracktor. So they had put something in their preload OS so the disk will not ever rest, and so, for that reason the disk doesn't spin down. After fresh install I did get the tracktor sound from the disk from time to time untill I upgraded the disk driver, and thus both problems were fixed.