[mythtv-users] Zotac memory ?

[Johnny]

>  4GB is listed as supported, but when we tested them, the bios was
> only able to see 3GB.
>
> About a week later they contacted me with a follow-up:
>
>  We re-tested it again. Upgrading from 3GB to 4 GB only gives you half
>  a gig more actual usable ram. We've enabled that option on the order
>  page if you're still interested in more than 3 GB.

This sounds like the standard 32-bit address space issue, that is an
issue for everybody in the x86 world not just Zotac or ION. The
address space is only 4GB minus addresses reserved for memory mapped
I/O (shared GPU memory, PCI, etc). However, most new BIOSes will use a
36 or 48 bit address space for the RAM and then let you map the memory
hole up to higher addresses so that a 64-bit OS can see the full 4GB
or more in the lower addresses. It seems that the Zotac bios doesn't
have support for memory remapping, so you will lose 1/2 to 1 GB of
addressable memory. But this is standard for any 32-bit OS or for an
motherboard that doesn't support memory remapping. It doesn't have
anything to do with being picky about certain RAM modules.

Incompatibilities between specific RAM modules and motherboards has
always baffled me. If it is DDR2-800 and you give it the specified
voltage it should work. That is the whole point of having a standard
specification. You don't see these weird incompatibilities, despite
having the correct specs, with other components. I haven't seen the
manufacturer giving a list of approved PCI cards or approved hard
drives, but they do this with RAM modules.