the issue is that the evo has a small amount of ram on the phone. not sure what htc was thinking when designing the evo. but there is the apps2sd that can be sort of helpful. when you go to settings/applications/manage apps and then move the apps to the sd card, you are using apps2sd. it moves the apps to the sd card, but it only moves part of the app to the card. the other part is still left on the phone. that is why you can't use any widgets attached to the app when it is moved to the card.
so what is taking up all of the ram then? well your phone, as it is, has the dalvik cache which the phone uses to load any executable files that it needs. and then there is cache where your temp files are stored. of course there is your apps. and finally there is the stock rom with sense 1.0. so you can see how fast your ram will disappear.
the only way to get around this is to be rooted. the custom roms that are out now are much smaller and faster then the stock rom. plus you can partition your card and use a2sd which is different then apps2sd. a2sd moves the entire app to your card. the only thing left on your phone is a symbolic link that tells the phone where to find the app on your card. it saves a ton of ram by doing this. just to give you an idea i have 160 apps with still 250mb left!
there are two types of a2sd scripts. one is cm a2sd and the other is darktremor a2sd. usually if a rom has a2sd cooked in, it usually has cm a2sd. when you flash your rom your apps when restored with titanium backup will automatically be move to the sd card. with darktremor a2sd, you would first need a rom to have support for it, and then you need to flash darktremor into the rom. once flashed then you can manually push the apps to the card by using terminal emulator to enter the commands.
you will need a higher class card to do this, preferably a class 6 or higher. the higher class card is need especially if you use intensive apps like games and such. the reason is that since the apps are on the card the phone then needs to read and write on the card as the app runs. so if you have a slower card your apps will suffer.
Partition Your Card
it is recommended that you do this before trying to flash a rom.
so here are the directions on how to do it:
1.copy your content of the card to a computer because partitioning will wipe the card's content.
2.go into recovery and select partition your sd card
3.enter 32 for swap, and 1024 or 2048 for ext2, and do the rest for FAT
4.select upgrade ext2 to ext3
6.select usb-ms toggle and transfer your contents of your card on your computer back to the card.
5.go to the main menu and do a full wipe (min data, dalvik cache and cache)
6.flash the superwipe
7.flash the rom of your choice.
8.reboot
from now on it is recommended you wipe dalvik cache, cache, data and sd ext.before flashing roms. MAKE SURE THAT YOU DO NOT SELECT WIPE SD CARD as it will do just that. your card will be erased. also make sure that when making a nandroid backup to select sd ext to be backed up as well.
