In the end, however, he is right. Subjective descriptions of a device becoming "slow" do not help diagnose any possible issues. In any case: Which memory? Remember, the N900 has multiple memory types: - RAM - Rootfs (256MB where the OS is stored) - eMMC which stores > /home - where all of your user settings are stored > /opt - where all installed applications go > swap - the 768MB Nokia adds to the ram to say 1GB - SD Card (which may or may not be there.) Filling the rootfs to 95-100 is known to cause problems, including being unable to do pretty much anything. The only issue I could see is if you have an application open so long that it begins to use all the ram and force things out to swap.