[10.10 64bit]-Why 8GB RAM Shows 7.8GB ?

[MR ZenWiz]

On Wed, Dec 22, 2010 at 2:06 PM, Ric Moore <wayward4now at gmail.com> wrote:
> On Wed, 2010-12-22 at 22:50 +0100, Thierry de Coulon wrote:
>> On Wednesday 22 December 2010 09:45:03 pm Jesse Palser wrote:
>> > [10.10 64bit]-Why 8GB RAM Shows 7.8GB ?
>> >
>> > Hi,
>> >
>> > Recently made the switch to the 64bit version of Ubuntu 10.10.
>> > I have 8GB DDR2 RAM installed on my computer
>> > but System Monitor shows only 7.8GB ?
>> > Where did 200MB RAM go?
>> > Thanks!
>> >
>> > Ubuntu is best OS...
>> >
>> > Jesse
>>
>>
>> Most probably the usual "kilobit/kilobyte" stuff: one kilobit is 1000 bit, 1
>> kilobyte is 1024; 1000/1024 is 0.9765 and 0.9765*8 is 7.8 so....
>
> I think that explanation is spot on. Ric
>
That would be true if the memory was actually 8,000,000,000 bytes, but
most memory measures are in traditional 2^x byte counts.  8GB of
memory should be 8,589,934,592 bytes (which is significantly more than
200MB > 8 billion).

The missing 200MB could be reserved for system use or something else -
are you running a 64-bit kernel or a 32-bit PAE kernel?