Does increased RAM size drain the battery faster?

Yes.

The memory uses power.

John Hay1 wrote:
Will increasing my brand-new MacBook 2.4 RAM to 4 gig drain my battery faster.

Probably not enough for you to notice. It might also depend on which brand/model of memory.

If you open the Activity Monitor and look at the System Memory tab at the bottom, do you have any "Page outs"? If you do, at some point you've run out of physical memory/RAM and your hard drive has been used for virtual memory. Using your hard drive for virtual memory will probably consume more power than more RAM will. So, it's possible that by adding more RAM and using your hard drive less for virtual memory will save you battery power. If you don't see any page outs accumulating, then you have no reason to purchase more RAM as you're not fully utilizing the RAM you already have.

-Doug

Much would depend on the part used. DDR3 operates at 1.5 and 1.35 V, so that helps with power consumption compared to DDR2. There's going to be power used for memory refresh. More power is going to be used when the memory is accessed.

I think one key would be how many parts (chips) are actually used. I/O uses a lot of power, so the ones with denser chips might use less power.

http://download.micron.com/pdf/technotes/ddr3/TN41_01DDR3%20Power.pdf

Micron actually has a spreadsheet to calculate all this:

http://download.micron.com/downloads/misc/ddr3powercalc.xls

John Hay1 wrote:
Will increasing my brand-new MacBook 2.4 RAM to 4 gig drain my battery faster.

Not quite, expanding your RAM of the same technology (DDR2 --> DDR2)? No. Expanding your RAM with newer technology (DDR2 --> DDR3)? Yes, but very minuet.

deltatux

deltatux wrote:

John Hay1 wrote:
Will increasing my brand-new MacBook 2.4 RAM to 4 gig drain my battery faster.

Not quite, expanding your RAM of the same technology (DDR2 --> DDR2)? No. Expanding your RAM with newer technology (DDR2 --> DDR3)? Yes, but very minuet.

DDR3 as a rule operates at a lower voltage and should almost always use less power than DDR2. I assume the original poster means DDR3 - increasing from 2x1GB standard to 2x2GB. I don't think it's enough to make a difference. Any performance increase will be well worth it and in some cases it can reduce power consumption.