Are there any know issues with memory size and/or type vs battery life?

I just bought a new memory card, a Dane-Elec 133 XS 4GB SD card. I installed it yesterday and now my N800 (OS2008) runs flat in about 8 hours of idle time!

Before changing the memory card (old one as a 1GB Micro SD in a holder) it would run for days idle.

Any ideas please

afaik, no there aren't. Do you have swap file turned on? This does make a difference, and people that have a swap file/virtual memory enabled were draining their batteries very quickly, at least under OS2007.

I haven't noticed any degradation on battery life on OS2008 when swap is enabled.

Flash memory doesn't consume any power when not being read or written, so it doesn't matter how big it is if you're not actively using it.

I've seen SD card reviews referring to low or high power consumption while manufacturers occasionally refer to (very) low consumption, obviously.

It would be nice to hear authoritative opinions from, say, Nokia's hardware people or even the tinfoil hats at the German C't or Popular Mechanics.

Also, larger cards tend to be faster (although good old 133x/150x SD cards are said to be faster than the newer SDHC Class 6 ones) so if they allow for faster reads/writes then the card should presumably spend longer in standby/sleep and thereby save power.

There are too many variables (usage, WIFI with/without power saving, batteries, temperature etc.) for any of us to make definitive statements without our personal FCC/EU/IEEE-approved home laboratory, but I would expect some cards to pull more juice than others while others might even have buggy circuitry.

I DID have a swap file on the card - removed it because it didn't seem to make any great difference to what I was doing.

I will try and do a bit more investigation over the next day or two and see if I can pin it down to anything else that might have changed when I swapped the card over.

You could also install one of the CPU monitoring status bar applets (e.g. load-applet-run) for easy checking of any unexpected CPU usage. There could be a crawler program or something else that has a problem with your new SD card, these kind of things have been reported to give problems like you described.