To read all comments associated with this story, please click here.
Well and a lot of your data (at least the pointers) are suddenly twice as big: you *need* more memory! Using < 4GB RAM with a 64bit OS gives less usable memory than with a 32bit OS. Only if you have significantly more than 4GB RAM 64bit has advantages memory wise. AMD64 has other advantages though: "better" assembler and twice as much registers -> this property should be faster. But bigger pointers = more memory to copy = slower memory operations. So some things are better with 64bit, some aren't.
An advantage of a 128 bit system over a 64-bit system would be the ability to natively process 128-bit numbers, which would speed up things like 128-bit file systems. Other than that, you get more potential address space for your programs. Which is dumb considering it would take a very long time for current systems to copy the equivalent of the contents of a full 64-bit address space (even at speeds of 1 TB per second it would take 213 days to read it all).
We seriously need to solve the problem of memory speed before we tackle memory limits higher than 64-bit.
"We seriously need to solve the problem of memory speed before we tackle memory limits higher than 64-bit."
That would be the primary reason in my mind for a move to >64 bit. Modern GPUs have 256- and even 512-bit wide memory buses (I don't know about addressing though).
Better from a board design standpoint is to get higher-speed, narrower interconnects as you noted.




Member since:
2009-09-17
Does anyone know what the advantage a 128 bit system has over a 64 bit system? I was under the impression that we had not yet even come close to making full use of a 64 bit system, so where would the use of 128 bit system show improvements.