Abstract: The processor throws fits like a baby when there is not enough memory bandwidth, something which can often keep it from performing up to its potential.|
RDRAM vs. DDR RAM; Does it Really make a Difference?
The Pentium 4 is known to
crave memory bandwidth above and over everything else. The processor throws
fits like a baby when there is not enough memory bandwidth, something which can
often keep it from performing up to its potential. This was evident
when Intel released their original i845 chipset which allowed a Pentium 4 to be
run with conventional SDRAM (hint: avoid like the plague).
Often a P4 equipped with SDRAM, running at
similar clock speeds could not beat a P3 at 1 GHz in terms of performance!
DDR alleviated the memory bandwidth bottleneck somewhat with the
i845D, delivering 2.1 GB/s worth of bandwidth as opposed to the 1.08 GB/s
SDRAM offered. That is still
a far cry from the 3.2 GB/s RDRAM can supply though, and today we're going
to take a look at whether the i850 "RDRAM" chipset is that much faster then the i845D "DDR"
times readers have been writing in to ask; "Is RDRAM really necessary for a
Pentium 4?" or maybe "I can't afford RDRAM, can I get by on DDR?" My personal favorite is; "I'm a speed freak on a budget, but can I get
good performance with a P4/DDR combo? ".
today I hope we set these questions to rest and answer what has been on the
minds of many; if Spiderman and Superman were in a battle who would win? We also
plan on pitting RDRAM vs. DDR RAM and seeing which
memory will be victorious - it is a battle royal that even
the great Spidy can 'sense'.
a whole bunch of DDR chipsets now for the Pentium 4, but we're going to be
focusing on Intel's own i845D. Why you ask? Intel has always produced fast and
very stable chipsets (other then the i820) and the i845D is no exception.
Based on the earlier i845 which was a very stable chipset in it's own, the i845D
only brings DDR capability to the table and nothing else. Actually there are no
real differences between the i845 or
i845D. Sure there's an official revision difference, but basically the i845D is
the i845 with DDR enabled.
The i850 board we are testing with
is the nice red MSI 850 Pro5 which has official support for
400 MHz based Pentium 4's using the Socket 478 format. We had a few i845D
based motherboards to choose from and eventually decided to keep it in the family and
test on the MSI 845 Ultra. Our testing processor is a Pentium 4 2.0 GHz
Williamette with 256KB L2 cache.
test system specs:|
||Pentium 4 2.0 GHz|
20 x 100 MHz = 2.0 GHz
Intel i850 (850Pro5)
Intel i845D (845
MSI GeForce 4 Ti4600 (300/660)
2x 128MB Samsung PC800 RDRAM
PC2700 DDR RAM
||40GB 7200RPM Maxtor D740X
||Panasonic 48x CD-ROM CR-594-B
Panasonic 1.44MB Floppy Drive
|| AVC Sunflower |
||Antec 400W PSU |
Content Creation 2001
SiSoft Sandra 2002
Please keep in mind when testing both systems, the
memory options were set to the most aggressive settings allowed in the