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Gomff

macrumors 6502a
Original poster
Sep 17, 2009
802
1
Hi all
Hope this is the right place for this thread.

I've recently installed Ubuntu 64 bit on my mac pro (for various reasons) and found that despite having 8GB RAM in the system, Ubuntu only sees 2GB.

My RAM configuration is 4 sets of 2GB sticks, 2 sticks in each memory board. There's 2GB in the first slots, then nothing in the second, then another 2GB in the third slots, then the fourth is empty. I spaced them out like this in the hope they might stay cooler....Dunno if it works or not. Anyhow, OS X and Windows 7 has no problems accessing all 8GB, it's just Ubuntu that can only see 2.

Does anyone have any ideas?

Thanks.
 
Yep, tried that....2 sticks in first 2 DIMM slots on both memory boards and still just get 2 GB showing up.

Any other ideas?
 
Thanks everyone for the advice....I've finally got to the bottom of it and feel pretty daft. Despite being certain I'd downloaded the 64 bit version, I was running the 32 bit somehow.

I then tried to install the 64 bit version which is confusingly labelled AMD 64bit but supposedly works on intel systems as well. This would not boot at all on my system, so I've opted to stay with 32 bit but have installed some pae packages which allow Ubuntu to see all 8GB, so I guess I'm almost where I wanted to be.

Even with Ubuntu, it seems there's a steep learning curve!
 
which is confusingly labelled AMD 64bit but supposedly works on intel systems as well.

That's because AMD invented the 64 bit standard currently used by AMD and Intel. Intel ripped it off when Itanic went nowhere. Hence, 'AMD64'.
 
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