Vital Statisics
We need
to cover a couple of basics here before we go too far in this duscussion.
The most obvious is that these processors cannot use the same motherboards.
I have to point that out because I'd hate to hear a story of bent pins
in a CPU socket. Intel's socket design used 370 pins while AMD's uses
420. That could end up being a deciding factor for a lot of people. I
realize that means you have to get a new board to move over to the Duron
or T-Bird but we'll leave that for the conclusion page. Let's go over
a couple of other factors here. The most logical order I could put them
in was FSB, Level 1 cache, and Level 2 cache.
FSB
The Athlon
front side bus is one of its most misunderstood concepts. When AMD released
the specs for the original Athlon there were many people who couldn't understand
the 200 MHz front side bus. Your memory and other components aren't running
at 200 MHz - there is a divider that brings things down to normal specs
for the other components. In all reality this doubling of the FSB is done
in such a way that most BIOS screens give you the option of changing the
system FSB in a way that looks very familiar. On the Azza board I used the
default was 100 and there were several increments upto 132 MHz. The question
immediately becomes why bother with such a high FSB? The answer boils down
to the fact that the FSB is one of the biggest bottlenecks in overall system
performance. When we raise the FSB on a Pentium III to 133 from the stock
100 MHz we see benefits in a lot of places - the most important being memory
and CPU performance. AMD's engineers saw that having a 200 MHz speed within
their CPU would mean that there would be higher performance potential moving
data from various areas within the processor and the Level 1 and Level 2
cache. One nice feature in all this is that AMD has promised a 266 Mhz FSB
in the future for their processors. You guessed it right - 133 MHz FSB for
our components is in the near future from AMD.
The Celeron
uses a 66 MHz bus. That is one of its most crippling problems that Celeron
users find. Of course this means that the most natural thing to do is to
overclock the CPU by changing the FSB to 100. Considering that a stock Duron
ships at 100 MHz system FSB that is a hurdle that the Celeron has a hard
time overcoming. It goes without saying that having your memory running
at 100 MHz FSB and your CPU at 200 FSB is much better than the 66 MHz the
Celeron uses.
Level
1 and Level 2 Cache
Cache is
memory that is incorporated into a processor to allow the temoporary storage
of data. While your CPU is working it will first store memory in the Level
1 cache, then the Level 2 cache, and finally the memory that is mounted
on the motherboard. This is why increasing the amount of memory you have
on your system can be such a big boost to performance. If both caches are
filled, and there isn't enough system memory, the data will be temporarily
written to your harddrive. That is a very slow way to get data back to the
CPU. The importance here is that the amount of cache, and its layout, can
have a big effect on performance.
The Duron
comes with 128K of Level 1 cache while the Celeron only has 32K. Having
such a large cache allows a large amount of temporary data to be stored
in the Level 1 cache which has the fastest access back to the CPU. There
isn't a whole lot to be said for the Celeron's 32K.
The Level
2 cache situation is pretty interesting. The Duron only comes with 64K while
the Celeron features 128K. Why so little for the Duron? With its very large
Level 1 cache it doesn't rely so heavily on the Level 2 cache. The Duron
800 is designed with the capacity to someday be built with 128K of Level
2 cache. With the Celeron running on a 66 MHz bus right now I don't think
there is a huge movement at AMD to implement this right now but I'm sure
it will happen about the same time that the Celeron moves to a 100 MHz bus.
Add them up and the Duron has a total of 192K of cache while the Celeron
has 160K. That looks pretty good for the Celeron except when you consider
that most of the Duron's cache is Level 1.
So we
know that we are comparing two different design philosophies here. Let's
get to the benchmarking!
