On 18:43 Sat 11 Aug , Aleksey V. Kunitskiy wrote: > On Friday 10 August 2007 22:34, Volker Armin Hemmann wrote: > > So your 'lost' memory is not really lost.... > Why? If I have 3G of memory it is OK and 4G is a problem. Of course a few > MB(~100 actualy) of memory is not critical for me in this case, but I'd like > to understand why 4G is problem where logical address space is 64 bit and > physical is about ~40 bit.
I think it's been explained pretty well in the 'ask Dan' link. I've read
through that and the article is really one of the best layman's tech
articles I've seen on the net so far.
See, the problem is that the PCI-addresses are all located at the upper
end of the 4Gig ram boundary. And _even if_ your system's already 64bit
the problem remains because of compatibility issues - hardware vendors
did not push the limit up (yet?) in order to be able to support
programs, drivers, OSs and other hardware that relys on PCI being
somewhere at the end of the 4Gigs... Some Mainboard vendors actually map
the stuff out with BIOS hacks in order to make more memory available.
This has happend on your machine because you only lack some lousy 100 MB
(Jesus, I remember my ultra-fast p100 (It was a cyrix though) that was
*so* proud of having 64 Megs...) which are used for PCI communications.
If you had an older mainboard you would probably lack those ~100 MB +
the amount of RAM your graphics card has, so, be happy ;-)
Regards,
Aleks
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