running a single core 64-bit as dual core 32-bit?

[CoMePrAdZ]

Okay, it's a fool question. (sorry about my bad english). can you make an gromacs fahcore who can utilizing single 64 bit as like as dual 32 bit? i looked that 64 bit has as twice as 32 bit's data and address bus ...

[7im]

There is no speed improvement for FAH using 64 bit hardware, and not for 64 bit FAH software. The software uses SSE for most of it's speed, and increasing bits from 32 to 64 did not change SSE.

[CoMePrAdZ]

thx for your reply, but i didn't mean like that ... i mean like this: when running 32 bit instruction on 64 bit cpu, we just utilize 32 bit, and another 32 bit are useless. so, can we utilize these useless bits for running another task(ex. second thread), but still using 32 bit OS? i think that it will using additional cpu driver ... (it's really my bad english ...)

[7im]

You would need a 64 bit OS to take full advantage of 64 bit hardware.

Still does not help FAH go faster. It may help other programs, but then we really only discuss FAH in this forum. Sorry.

[bruce]

thx for your reply, but i didn't mean like that ... i mean like this: when running 32 bit instruction on 64 bit cpu, we just utilize 32 bit, and another 32 bit are useless. so, can we utilize these useless bits for running another task(ex. second thread), but still using 32 bit OS? i think that it will using additional cpu driver ... (it's really my bad english ...)

This simply is not true. A single SSE instruction operates on 128 bits of data. It can perform four single precision floating point operations simultaneously or two double precision floating point instructions. Using double precision gets less work done and FAH doesn't really need the extra precision. These operations do not use the 32-bit or 64-bit integer registers that you're thinking about.

[CoMePrAdZ]

Oww, like that ... i know what you mean. now i know why in the task manager fahcore_82.exe process have 4 threads. thanks for all reply ...