as much as i hate to suggest it, the 12 penny trick may fix that problem, because the 12 penny trick puts pressure on the ram chips. A better way would be to identify the ram and resolder the legs, or if yours dont have legs use a hot air gun to "reflow" the solder. some people put heatsinks on the ram in order to prevent it again, but that is not a fact that it does anything for you(more heatsinks wont hurt anything, it is just unprovent that it will help).
I believe the ram are the ones with teh thermal pads that look like bandaides when you dissasemble your xbox, on the versions that have those.
