Memory Q: 1gb dual channel 320mhz or 2gb single channel 266mhz?

[KenV]

This one isn't a problem, just sort of a thought experiment, if you enjoy this
sort of thing..

I have a P4P800E-Deluxe with a P4 2.8c processor. (Some of this has been
discussed in another thread concerning dual channels.)

Finally, after much soul-searching I have decided to replace or maybe
supplement my old Crucial PC2700 512mb mismatched (one single bank, other dual
bank) sticks with a matched set of Crucial PC3200 512mb sticks, which I will
then place in the blue slots.

Now, should I expect to get better performance with only those two sticks in
place, 1 gb of 333mhz (really 320mhz) dual channel, or if I add the two 512
PC2700 mismatched 512 sticks in the black slots, thus giving a total of 2gb
memory, but which will revert the system to single channel mode running at
266mhz. Does it depend upon the application? For example, when I use Ghost to
make backups, it slows the computer down tremendously, and according to the Task
Manager uses about 75% of the memory while it is working. If I double the
memory, will it still use the same 75%?

How could I test this other than judging by the "feel" of the computer?

Ken

 

[Paul]

This one isn't a problem, just sort of a thought experiment, if you enjoy this
sort of thing..

I have a P4P800E-Deluxe with a P4 2.8c processor. (Some of this has been
discussed in another thread concerning dual channels.)

Finally, after much soul-searching I have decided to replace or maybe
supplement my old Crucial PC2700 512mb mismatched (one single bank, other dual
bank) sticks with a matched set of Crucial PC3200 512mb sticks, which I will
then place in the blue slots.

Now, should I expect to get better performance with only those two sticks in
place, 1 gb of 333mhz (really 320mhz) dual channel, or if I add the two 512
PC2700 mismatched 512 sticks in the black slots, thus giving a total of 2gb
memory, but which will revert the system to single channel mode running at
266mhz. Does it depend upon the application? For example, when I use Ghost to
make backups, it slows the computer down tremendously, and according to the Task
Manager uses about 75% of the memory while it is working. If I double the
memory, will it still use the same 75%?

How could I test this other than judging by the "feel" of the computer?

Ken

To measure the available bandwidth on the memory, I use
the bandwidth display item in the upper left hand corner
of the memtest86+ memory test program. SiSoft Sandra has
a memory bandwidth benchmark that people use as well.

On my P4C800-E, memory plugged in a single channel config
measures 1681MB/sec, while the same memory with the same
timings measures 2732MB/sec in dual channel mode. That may
seem like a large difference, but the application impact
will be a lot less. In a way, this kind of bandwidth
measurement is useless, except to quantify the impact
that various features make to memory performance. On some
of the enthusiast sites, it is also fun to compare numbers
with your friends

If you are transcoding a movie, or doing something with
a long run time, using a stopwatch will tell you the
impact of your two configurations.

I cannot say that I'm particularly impressed with a
number of benchmark programs they use on the popular
sites like Anandtech. Does PCMark reflect what I do ?
Do the descriptions of what is being modelled in some
of the other tests seem like realistic scenarios ? I think
it is better to rely on things you can measure, on
the applications you own and use every day.

Photoshop is likely to see a measurable difference
between the two configurations. To make the comparison
really fair, so you are measuring the diff between
single and dual channel, I would crank the RAM to PC2700
rates for both tests, and use 1GB SC and 1GB DC
configs for your two tests. Otherwise, Photoshop may
benefit from having the extra GB of RAM in one of your
cases. There are Photoshop "action" scripts that will
run an automated set of commands, and are used as
benchmarks by Photoshop users. Timing those would
show you the impact of SC versus DC when using a
memory intensive program.

Since my normal usage pattern hardly makes a dent
in my 2x512MB config, I'd have to say I'd
pick the 2x512MB PC3200 DC config. Doing Photoshop
type things happens seldom enough that I don't
think I'd plan my memory config around that
usage. I'd need to be using very big images
before I'd plug in the rest of the RAM.

Your Ghost experience seems strange. Have you
ever tried to find the reason for the large
memory consumption ? Maybe it is a bug and
Symantec has a fix for it.

Paul

 

[Egil Solberg]

This one isn't a problem, just sort of a thought experiment, if you
enjoy this sort of thing..

I have a P4P800E-Deluxe with a P4 2.8c processor. (Some of this has
been discussed in another thread concerning dual channels.)

Finally, after much soul-searching I have decided to replace or
maybe supplement my old Crucial PC2700 512mb mismatched (one single
bank, other dual bank) sticks with a matched set of Crucial PC3200
512mb sticks, which I will then place in the blue slots.

Now, should I expect to get better performance with only those two
sticks in place, 1 gb of 333mhz (really 320mhz) dual channel, or if I
add the two 512 PC2700 mismatched 512 sticks in the black slots, thus
giving a total of 2gb memory, but which will revert the system to
single channel mode running at 266mhz. Does it depend upon the
application? For example, when I use Ghost to make backups, it slows
the computer down tremendously, and according to the Task Manager
uses about 75% of the memory while it is working. If I double the
memory, will it still use the same 75%?
How could I test this other than judging by the "feel" of the
computer?
Ken

I have 1GB RAM installed. As judging by taskmgr, I have never used that
much, at most 6-700MB. If it is the same for you, the 1GB DC setup will be
fastest. If you need to use more than 1GB RAM often, running 2GB SC will be
fastest. The question is: Do you need over 1GB RAM? For all other purposes
the 1GB DC setup will be much faster.

 

[KenV]

I have 1GB RAM installed. As judging by taskmgr, I have never used that
much, at most 6-700MB. If it is the same for you, the 1GB DC setup will be
fastest. If you need to use more than 1GB RAM often, running 2GB SC will
be fastest. The question is: Do you need over 1GB RAM? For all other
purposes the 1GB DC setup will be much faster.

Since my normal usage pattern hardly makes a dent
in my 2x512MB config, I'd have to say I'd
pick the 2x512MB PC3200 DC config. Doing Photoshop
type things happens seldom enough that I don't
think I'd plan my memory config around that
usage. I'd need to be using very big images
before I'd plug in the rest of the RAM.

Your Ghost experience seems strange. Have you ever tried to find the
reason for the large
memory consumption ? Maybe it is a bug and Symantec has a fix for it.

Egil and Paul,

Thanks! Very useful information, and it makes total sense that it's better
to have 1 gb of fast memory than 2gb of slower memory if you're not using
more than 1 gb of memory in the first place.

I am going to contact Symantec about the Ghost problem. I suspect they are
going to tell me to buy their version 10.0 which, unlike the 9.0 I have,
apparently has a priority setting where you can more or less control the
memory usage. Whether it's worth the $50 or so for the upgrade is another
matter.

Ken