Upgrading the RAM doesn't make the games run bad at all, it doesn't make any difference to the games UNLESS you delimit the games, there is a patch available to RAM delimit the games which is available in the usual places, this CAN make a difference, games CAN run smoother but most games it doesn't do much for these.
Being as alot of RAM is ran at slower speeds than it should be in the xbox then adding the extra RAM can make it more stable, i think one of the biggest differences is in Halo.
Its great for use in XBMC, Linux, And especially emulators ie mame and the N64 emulators!
Also as above, its good for using when debugging, but being as the retail boxes are MCPX X3's and not the X2's then this doesn't allow everything that the original debugging machines can do, although it does come reasonably close depending upon the applications you wish to use this for.
Having said the above, some of the original debugging consoles like the live betas only ever came with the standard 64MB type so this isn't always required for different useages and will run alot of stuff fine with only 64MB RAM.
As for installing the extra RAM, only V1.0-1.5 boxes are capable of having the 128MB RAM upgrade done, the V1.6a+b are not compatable as there are no solder pads, the V1.0-1.1 can use any version xbox RAM providing its of the Samsung brand and not from a 1.6b motherboard.
the v1.2-1.5 boards use the newer version Samsung RAM and are not compatable with the older RAM from the version 1.0/1.1 motherboards.
Soldering the RAM is abit of a professional job, unless you have some pretty professional soldering skills i recommend you don't give this a go, simply because the chances of you pulling this off and it working correctly are so low. Even for someone with pretty professional soldering skills, getting this to work 100% fine can be abit tricky some times, ive had good experience considering how many boards i have actually upgraded.
I hope ive cleared a few things up here.
Good luck to anyone attempting to RAM upgrade
EDIT: If you want a tutorial check out the sections above in this forum the general hardware guide should have a working tutorial or check out the xbox linux website for more information and a reasonable tutorial.
You can remove the RAM from other xbox motherboards, most people including me remove it from dead boards that have other faults, but having said this you can buy it brand new, but its difficult to get hold of, and more often than not quite expensive.This post has been edited by Dano2k0: Jan 4 2006, 05:39 PM