[npeterh]

Hi,

I just got the 15 inch PB and am considering adding 1Gig.
Will this decrease battery life significantly so I should consider just adding 512k instead?

Any ideas?

My theory is that the added memory will decrease hard drive usage so it should be evened out.
correct?

Thanks

[Big Mac]

Not only is your hypothesis essentially correct, RAM does not use that much energy anyway. If you can afford it, max your laptop RAM. It's a fine investment for everyone except those who have very light usage patterns.

[phantomo]

I would say you have battery saving by getting 1G or 512MB RAM (should be very closed). The amount used by the RAM chips are far less than HD swapping between files. So the determining factor is the programs memory usage and the number of pograms you load concurrently.

[mduell]

I disagree with the popular belief on these forums that more RAM will not decrease battery life.

According to the manufacturers, 512MB DDR2 RAM uses about 1.5W.
The difference in power draw between an idling laptop hard drive and one that is seeking/reading/writing is about 1.5W.

So you will see no change in battery life if you're constantly swapping to virtual memory (which would be a miserable situation to be in). Under any other scenario, battery life will decrease with more RAM.
But of course if the additional RAM lets you work more efficiently/quickly, you may be more productive despite the shorter battery life.