...actually there is a benefit for defragmenting memory.
Consider having 1GB of physical RAM out of wich just 512MB are allocated but the memory is fragmented in such a way that there is no more than 2 MB of free space between each fragment.
Now if a program wants to allocate a continuous block of RAM larges than 2MB it will find no space in physical RAM and will use the swap file even if there are 512MB free in physical RAM.
So in a scenario where there are many (hundreds) of processes constantly appearing and dissapearing (in case of servers) you may start to see a lot of swapping even when there is free space in the physical RAM, in this case defragmentation of RAM helps.
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...actually there is a benefit for defragmenting memory.
Consider having 1GB of physical RAM out of wich just 512MB are allocated but the memory is fragmented in such a way that there is no more than 2 MB of free space between each fragment.
Now if a program wants to allocate a continuous block of RAM larges than 2MB it will find no space in physical RAM and will use the swap file even if there are 512MB free in physical RAM.
So in a scenario where there are many (hundreds) of processes constantly appearing and dissapearing (in case of servers) you may start to see a lot of swapping even when there is free space in the physical RAM, in this case defragmentation of RAM helps.