On Mon, 21 Mar 2005 13:41:41 -0500, Ivica Ico Bukvic <ico@email-addr-hidden> wrote:
> > I have an amd64 running in 64 bit mode. There honestly isn't much
> > reason to get a 64 if you are going to run in 32 bit mode...They are
> > way more expensive than the 32 bit counterparts and don't offer enough
> > extra in 32 bit mode.
>
> FWIW, I strongly disagree. You get much better performance per clock on a
> 64-bit machine even when running in 32-bit simply due to chip architecture
> improvements including SSE2 among other things, and the price should not be
> that different when compared with the 32-bit offering (as long as you don't
> go for the FX stuff). Also, heat dissipation as well as battery life (if
> considering laptop) is definitely a plus when compared with Pentium4
> offering. Pentium-M processors are also nice but also generally more
> expensive.
I am of course not talking about Intel processors, which are always
way overpriced, when I compare price between 64bit and 32bit. Maybe
the prices of 64 AMDs has gone down considerably but when I bought
mine the price was at least 5x greater than a 32 bit at the same
speed.
BTW, I am pretty sure the SSE2 registers are only available in 64bit
mode. I used the amd64 as my target platform in my os "design" for
college. If I recall correctly the SSE2 registers are one of many
things that become unavailable in 32bit legacy mode (the mode used
when you run a 32 bit OS), and this includes the expanded memory
addressing. In compatability mode, where the os is 64bit but the app
is 32, they might be available. I could have my mode names
reversed...
In short, when you run the 64bit processor as a 32bit processor you
loose almost all of the enhancements made in the new design. You
probably actually have better features with an actual 32 bit processor
than you do with a 64 in 32 mode.
Received on Tue Mar 22 04:15:13 2005
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