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Thread ID: 125153 2012-06-09 17:03:00 32 bit v 64 bit Vince (406) Press F1
Post ID Timestamp Content User
1280754 2012-06-10 06:58:00 Actually I was not quite up to date - some have a 44 bit address bus: 2^44 = 17,592,186,044,416 bytes = 7,592,186,044,416/ 1,073,741,824 = 16,384 GiB johnd (85)
1280755 2012-06-10 12:40:00 If you wish to run old 16-bit software in windows directly, you need 32-bit windows, as 64-bit windows can only emulate 32-bit, not 16-bit. Agent_24 (57)
1280756 2012-06-10 23:52:00 Not sure that this is true? To my knowledge 64 bit CPUs have a 64bit data bus but usually only a 36 bit address bus - so 2^36 = 68,719,476,736Bytes. (68,719,476,736/ 1,073,741,824= 64GB).

Even something old like AMD's original Athlon64 K8-series can address up to 1TB of RAM. Most current desktop CPUs can address up to 256TB of RAM (48-bit address space). I'm not aware of any consumer-level 64-bit desktop processor with less than 40-bit address space.
inphinity (7274)
1280757 2012-06-11 10:25:00 Even something old like AMD's original Athlon64 K8-series can address up to 1TB of RAM. Most current desktop CPUs can address up to 256TB of RAM (48-bit address space). I'm not aware of any consumer-level 64-bit desktop processor with less than 40-bit address space.

Yep - partially corrected in my previous post - the main point is that 64 bit CPUs don't have a 64 bit address bus.
johnd (85)
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