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The top speed of the Intel Celeron and AMD Duron processors (CPU's) is 1.3
GHz. The top speed of the Intel Pentium 4 and the AMD Athlon are 2.53 GHz and
=2.2 GHz, respectively. Most P4's and Athlons sold today are faster than 1.3
GHz. However, suppose you have 4 systems: 1.3 GHz Celeron, Duron, P4, and
Athlon. The difference is with the memory inside the CPU called the cache, the
type of memory the system uses, and the additional multimedia commands the CPU
can handle.
The cache is expensive to build into the CPU because it makes the physical die
size larger. The larger the cache, the less the CPU must reach into main
memory which is farther away and slower. The Celeron and the Duron are the
budget cpu's. They have a smaller cache. The P4 and the Athlon have a larger
cache. Some specialized Pentiums, called Xeons, have 1 MB of cache and cost
over $3,000. If you want cache sizes, go here:
http://www.geek.com/procspec/procspec.htm
Without opening the box, it can sometimes be difficult to figure out what type
of main memory sticks a system uses. It can be either, by order of speed and
expense, SDRAM, DDR-RAM, or RDRAM. AMD CPU's only use SDRAM and DDR-RAM.
Until this year, most P4 systems only had RDRAM installed. Intel decided to
reduce their RDRAM commitment and support SDRAM and DDR-RAM. SDRAM is oldest
and slowest standard. A system with SDRAM, no matter how fast the CPU, would
be slower when creating large ZIP files, multimedia files, handling video,
etc... RDRAM is the most expensive and the fastest. However, because the
Athlon is so enhanced, at the same speed with DDR-RAM it is usually faster than
a P4 with RDRAM.
Beginning with the Pentium in 1995-6, CPU makers started including extra
multimedia command sets. These commands are additional features and are there
for programmers to exploit. I don't remember them all or all the details. The
Celeron can use MMX, SSE, SSE2; Duron MMX, 3DNow!; Pentium 4 MMX, SSE, SSE2;
Athlon Thunderbird MMX, 3DNow!, Enhanced 3DNow!; and Athlon XP & ThoroughBred
MMX, 3DNow!, Enhanced 3DNow!, SSE. These command sets are used to accelerate
multimedia functions in games, playing DVD's, possibly music, etc... Not all
games and apps exploit all advantages in a CPU. Very few applications use SSE2
commands or Enhanced 3DNow!. Even so, games and applications have no problems
running on all 4 CPU's.
Because this is such a complex subject, it is difficult to be brief. This is
about as simple as you can get without throwing out details. Below is
additional material concerning a new CPU.
Personally, I prefer the AMD line of CPU's. Late this year, the new AMD K8
(Opteron and ClawHammer) arrives. The K8 will have 64-bit capability and, more
importantly, a built-in memory controller. Unlike the new Intel Itanium, the
K8 has native 32-bit support which means it should be just as fast as AMD's
current Athlon CPU's with standard apps. Because the K8's memory controller is
built-in, it should be much faster when moving large amounts of data. Unlike
all previous AMD CPU's which have their memory controller on the motherboard,
the K8's onboard memory controller should fully exploit any DDR-RAM used with
it. The Abit KG7-RAID motherboard I purchased in September uses the AMD 760
chipset which has a slow memory controller. While subtle, the speed
limitations are noticeable while moving large amounts of data.
Daniel.
Jim wrote:
> No doubt this is obvious to many but not to me:-
>
> Would someone briefly explain in laymans terms why it matters which type of
> processor (pentium/celeron/athlon) is in use if their quoted speeds are the
> same.
>
> TIA
>
> Jim
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