Archived from groups: comp.sys.ibm.pc.hardware.chips (More info?)
"Anonymous Joe" <anonymousjoe@net.net> wrote in message
news:TlWkc.7010$Ia6.809665@attbi_s03...
> "Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
> news:6RUjc.3959$0j3.1020@newssvr23.news.prodigy.com...
> > Paul Tiseo <tiseo123.paul456@mayo.edu> wrote:
> > > If you spend umpteen million in R&D to design the P4, and the P-M
> > > comes along with less R&D and runs slightly faster in some scenarios,
> > > what do you do? Chuck all your P4 R&D out the window?
> >
> > Actually, I believe the Pentium4 was done as a rush job,
> > on the cheap after it became apparant that ia64 (aka
> > Itanium) would not take over. IMHO it's an original
> > Pentium plus SSE2, deeply pipelined for inflated clocks.
> >
> > The Pentium-M is little more than the venerable P6 core,
> > tweaked and clocked higher on smaller processes.
> >
> > -- Robert
>
> It does seem as though the P4 is just that. A P3 with SSE2, with very
long
> pipelines (extended further thanks to Prescott) for a hyper-inflated clock
> speed that eventually is pretty decent, but only when you get to a
> ridiculous level of clock speed, and some of that is due to the quadrupled
> bandwidth bus speed combined with the memory speeds (dual channel
anyways).
> As the P4 increases in clock speed, so does the L1/L2 cache, which can
only
> help but improve performance further.
>
> What strikes me is that a P4 @ 3GHz is generally on par with an Athlon
> 3000+, which depending on the bus speed chosen is either 2.16GHz (333Mhz
> bus) or 2.1GHz (400Mhz bus). I forget off-hand how deep the P4 pipeline
is,
> but is something like 24, isnt it? The Athlon is something like 12, or
15.
> Either way, the numbers are off, but it still is rather close. The P4 has
> L1 & L2 cache running at 3GHz, while the Athlon's is about 66% of that,
but
> more plentiful. The bus bandwidth of the P4 is going to be either
> 4.27GB/sec or 6.4GB/sec (533 or 800MHz bus [yet it is really 133 or
> 166MHz]). Yet the Athlon is using a 3.2GB/sec bus. As for memory, the
most
> you can get out of the Athlon is the 3.2GB/sec (whether you use P3200 RAM,
> any speed dual channel RAM, even PC3200), but with P4 you have a shot at
> getting a theoretical of 6.4GB/sec (dual channel PC3200).
>
> All this combined, things sure look favorable for P4. It has so much more
> bandwidth in every area, cache, bus, and RAM. Yet, how come with a 900MHz
> core clock lead, it is only able to tie the Athlon? It seems like it is
> using all the bandwidth and wasting it. If AMD could get the sort of
> bandwidth that Intel has, I would imagine that the P4 would need about a
> 1200MHz or more head start to start being comparable.
>
> For anybody who cares, I do use AMD, so if you want to say I'm promoting
AMD
> unfairly or whatever, that's wrong, I'm simply showing that Intel isn't
> efficient.
>
>
In my opionion(2 ?cents worth) that's exactly the opposite of bragging
rights, those numbers. When we consider the problems they constantly bring
out related to Moore's law and heat dissipation and all that stuff related
to miniaturization reaching it's final barrier, every FLOP/Hz, B/s and
transistor saved should mean more than ever and P4 design looks right in the
eye of the problem and smugs: yes, but my pipe is longer...
"Anonymous Joe" <anonymousjoe@net.net> wrote in message
news:TlWkc.7010$Ia6.809665@attbi_s03...
> "Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
> news:6RUjc.3959$0j3.1020@newssvr23.news.prodigy.com...
> > Paul Tiseo <tiseo123.paul456@mayo.edu> wrote:
> > > If you spend umpteen million in R&D to design the P4, and the P-M
> > > comes along with less R&D and runs slightly faster in some scenarios,
> > > what do you do? Chuck all your P4 R&D out the window?
> >
> > Actually, I believe the Pentium4 was done as a rush job,
> > on the cheap after it became apparant that ia64 (aka
> > Itanium) would not take over. IMHO it's an original
> > Pentium plus SSE2, deeply pipelined for inflated clocks.
> >
> > The Pentium-M is little more than the venerable P6 core,
> > tweaked and clocked higher on smaller processes.
> >
> > -- Robert
>
> It does seem as though the P4 is just that. A P3 with SSE2, with very
long
> pipelines (extended further thanks to Prescott) for a hyper-inflated clock
> speed that eventually is pretty decent, but only when you get to a
> ridiculous level of clock speed, and some of that is due to the quadrupled
> bandwidth bus speed combined with the memory speeds (dual channel
anyways).
> As the P4 increases in clock speed, so does the L1/L2 cache, which can
only
> help but improve performance further.
>
> What strikes me is that a P4 @ 3GHz is generally on par with an Athlon
> 3000+, which depending on the bus speed chosen is either 2.16GHz (333Mhz
> bus) or 2.1GHz (400Mhz bus). I forget off-hand how deep the P4 pipeline
is,
> but is something like 24, isnt it? The Athlon is something like 12, or
15.
> Either way, the numbers are off, but it still is rather close. The P4 has
> L1 & L2 cache running at 3GHz, while the Athlon's is about 66% of that,
but
> more plentiful. The bus bandwidth of the P4 is going to be either
> 4.27GB/sec or 6.4GB/sec (533 or 800MHz bus [yet it is really 133 or
> 166MHz]). Yet the Athlon is using a 3.2GB/sec bus. As for memory, the
most
> you can get out of the Athlon is the 3.2GB/sec (whether you use P3200 RAM,
> any speed dual channel RAM, even PC3200), but with P4 you have a shot at
> getting a theoretical of 6.4GB/sec (dual channel PC3200).
>
> All this combined, things sure look favorable for P4. It has so much more
> bandwidth in every area, cache, bus, and RAM. Yet, how come with a 900MHz
> core clock lead, it is only able to tie the Athlon? It seems like it is
> using all the bandwidth and wasting it. If AMD could get the sort of
> bandwidth that Intel has, I would imagine that the P4 would need about a
> 1200MHz or more head start to start being comparable.
>
> For anybody who cares, I do use AMD, so if you want to say I'm promoting
AMD
> unfairly or whatever, that's wrong, I'm simply showing that Intel isn't
> efficient.
>
>
In my opionion(2 ?cents worth) that's exactly the opposite of bragging
rights, those numbers. When we consider the problems they constantly bring
out related to Moore's law and heat dissipation and all that stuff related
to miniaturization reaching it's final barrier, every FLOP/Hz, B/s and
transistor saved should mean more than ever and P4 design looks right in the
eye of the problem and smugs: yes, but my pipe is longer...
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