1GB matching DDR vs 1.25GB DDR non matching

[jrmwillis]

I currently have 2 sticks of 256MB DDR memory in my machine and I want
to increase this to at least 1GB. Am I better off getting two matching
512MB sticks or buying a single 1GB stick and leaving one of the 256MB
sticks in place.

The first scenario gives me a total of 1GB but theoretically faster
memory
the second scenario gives me a total of 1.25GB but I would miss out on
the speed enhancement of DDR

Can anyone give me some advice?

 

[Paul]

I currently have 2 sticks of 256MB DDR memory in my machine and I want
to increase this to at least 1GB. Am I better off getting two matching
512MB sticks or buying a single 1GB stick and leaving one of the 256MB
sticks in place.

The first scenario gives me a total of 1GB but theoretically faster
memory
the second scenario gives me a total of 1.25GB but I would miss out on
the speed enhancement of DDR

Can anyone give me some advice?

Motherboard brand/model or chipset used ? Matched pairs might
give you dual channel, which is a little better than forcing
your motherboard into a virtual single channel mode. Or, depending
on which Athlon64 processor stepping you've got, three sticks
simply won't run.

You'd better give details if you want a good answer. Like motherboard
brand/model (and CPU type/stepping if it is Athlon64/FX).

Paul

 

[jrmwillis]

I don't really know what motherboard I have, how would I go about
figuring that out?

The computer is a Gateway 901x it has 2 memory slots with 2x 256MB
sticks right now. Here are the memory specs that they give me:

Two 184-pin DIMM sockets
Dual-channel (128 bits wide) DDR memory interface
Single-channel (64-bits wide) DDR operation supported
Types of DIMM: 128 megabyte (MB), 256 MB, or 512 MB non ECC DDR 400
modules.
Maximum Capacity: 2 gigabytes (GB)

This is a link to the MB spec:

http://support.gateway.com/s/PC/901_Series/2900090/2521072/2521072sp9.shtml

Processor: Intel® Pentium® 4 Processor 3.0GHz with Hyper-Threading
Technology
Memory: 512MB 400MHz DDR SDRAM

Anything else I can lookup to help?

 

[kony]

I currently have 2 sticks of 256MB DDR memory in my machine and I want
to increase this to at least 1GB. Am I better off getting two matching
512MB sticks or buying a single 1GB stick and leaving one of the 256MB
sticks in place.

The first scenario gives me a total of 1GB but theoretically faster
memory
the second scenario gives me a total of 1.25GB but I would miss out on
the speed enhancement of DDR

Can anyone give me some advice?

What are you doing with the system? My point is, if you
won't be using more than 850MB or so of memory (leaving the
remainder of 1GB for a filecache) then don't install the
mismatched memory just to get to 1.2GB, install only 2 x
512MB. If your jobs will exceed 850GB used, install 1 x 1GB
plus at least one (if not both) of the 256MB.

 

[Paul]

I don't really know what motherboard I have, how would I go about
figuring that out?

The computer is a Gateway 901x it has 2 memory slots with 2x 256MB
sticks right now. Here are the memory specs that they give me:

Two 184-pin DIMM sockets
Dual-channel (128 bits wide) DDR memory interface
Single-channel (64-bits wide) DDR operation supported
Types of DIMM: 128 megabyte (MB), 256 MB, or 512 MB non ECC DDR 400
modules.
Maximum Capacity: 2 gigabytes (GB)

This is a link to the MB spec:

http://support.gateway.com/s/PC/901_Series/2900090/2521072/2521072sp9.shtml

Processor: Intel® Pentium® 4 Processor 3.0GHz with Hyper-Threading
Technology
Memory: 512MB 400MHz DDR SDRAM

Anything else I can lookup to help?

No, that is a good amount of info. A P4 S478 motherboard with Intel chipset.

The 865G chipset, has the ability to work in dual channel.

You can buy 2x512MB or 2x1GB DDR PC3200 (i.e. DDR400), and replace the 2x256MB
you currently have. [A DIMM is 64 bits wide, or 8 bytes. Multiplying the transfer
rate (400) by the width of the module (8 bytes), gives the bandwidth of
3200MB/sec or PC3200.]

Basically the same advice shown on this page for FMC-901X:

http://www.jenkco.com/product_submodel.php?ID=28089

Can you replace just one stick ? Yes, you can. But then the motherboard
will run in virtual single channel mode. That will have a small impact
on application performance. In Figure 3 here, a number like 7% or 8%
performance difference seems believable.

http://www.intel.com/design/chipsets/Dual_DDR_SB.pdf

Is the difference detectable ? Yes, it is. I bought a computer for a relative,
and it was supposed to come with dual channel memory. The product was
assembled locally, and I could tell by the screen update times, that something
was wrong. The memory sticks were not matched. Once the error was
corrected, the screen update was a little snappier. So the 865G graphics
do appreciate the advantage of dual channel memory. (Less so if a
separate AGP video card is being used.)

2x1GB kits start around $200, and there are a couple of CAS2 products
for $218.99 and $230.99. Read the customer reviews, to see if the
users find them good or not. CAS3 is a bit slower, but not much
cheaper.

http://www.newegg.com/Product/Produ...Subcategory=147&description=&Ntk=&srchInDesc=

2x512MB should be half that price.

Paul

 

[jrmwillis]

OK,

Right now I am running Vista and using the box as a media center hub.
Currently about 480MB of my 512MB is used and that is when I am not
actually doing anything on the machine itself...

It is an older machine and I don't want to push the memory to 2GB
because the other components will be lagging and its not worth the
investment. It obviously cannot carry on the way it is with almost no
free memory when sitting idle.

an 8% performance hit seems realtively low for me, as the machine is
doing what it needs to right now (streaming TV/Audio to my xbox 360).
SO I wonder given this information that I would be better getting
asingle 1GB stick and replacing one of the 256 and getting single speed
but more raw memory.

OR the fact that I am currently using about 480MB and that is about as
high as it needs to go for what it is going to be doing suggests that
1GB is enough.

Thanks again

I don't really know what motherboard I have, how would I go about
figuring that out?

The computer is a Gateway 901x it has 2 memory slots with 2x 256MB
sticks right now. Here are the memory specs that they give me:

Two 184-pin DIMM sockets
Dual-channel (128 bits wide) DDR memory interface
Single-channel (64-bits wide) DDR operation supported
Types of DIMM: 128 megabyte (MB), 256 MB, or 512 MB non ECC DDR 400
modules.
Maximum Capacity: 2 gigabytes (GB)

This is a link to the MB spec:

http://support.gateway.com/s/PC/901_Series/2900090/2521072/2521072sp9.shtml

Processor: Intel® Pentium® 4 Processor 3.0GHz with Hyper-Threading
Technology
Memory: 512MB 400MHz DDR SDRAM

Anything else I can lookup to help?

No, that is a good amount of info. A P4 S478 motherboard with Intel chipset.

The 865G chipset, has the ability to work in dual channel.

You can buy 2x512MB or 2x1GB DDR PC3200 (i.e. DDR400), and replace the 2x256MB
you currently have. [A DIMM is 64 bits wide, or 8 bytes. Multiplying the transfer
rate (400) by the width of the module (8 bytes), gives the bandwidth of
3200MB/sec or PC3200.]

Basically the same advice shown on this page for FMC-901X:

http://www.jenkco.com/product_submodel.php?ID=28089

Can you replace just one stick ? Yes, you can. But then the motherboard
will run in virtual single channel mode. That will have a small impact
on application performance. In Figure 3 here, a number like 7% or 8%
performance difference seems believable.

http://www.intel.com/design/chipsets/Dual_DDR_SB.pdf

Is the difference detectable ? Yes, it is. I bought a computer for a relative,
and it was supposed to come with dual channel memory. The product was
assembled locally, and I could tell by the screen update times, that something
was wrong. The memory sticks were not matched. Once the error was
corrected, the screen update was a little snappier. So the 865G graphics
do appreciate the advantage of dual channel memory. (Less so if a
separate AGP video card is being used.)

2x1GB kits start around $200, and there are a couple of CAS2 products
for $218.99 and $230.99. Read the customer reviews, to see if the
users find them good or not. CAS3 is a bit slower, but not much
cheaper.

http://www.newegg.com/Product/Produ...Subcategory=147&description=&Ntk=&srchInDesc=

2x512MB should be half that price.

Paul

 

[kony]

OK,

Right now I am running Vista and using the box as a media center hub.
Currently about 480MB of my 512MB is used and that is when I am not
actually doing anything on the machine itself...

Why?

You don't need Vista for a media center hub, it will require
an expensive license, usurp more memory to do the same job.

It is an older machine and I don't want to push the memory to 2GB
because the other components will be lagging and its not worth the
investment. It obviously cannot carry on the way it is with almost no
free memory when sitting idle.

Then optimize it for it's intended use. Win2k or XP could
get by as a hub with 256MB total, easily. If you had a
unique use that benefits from a lot of filecaching, a few
gigs of memory might help, but just a little more (like 1GB)
won't be so useful because each (video) media file has the
potential to be several GB in size, it's not as though you'd
be able to cache several for simultaneous access.

an 8% performance hit seems realtively low for me, as the machine is
doing what it needs to right now (streaming TV/Audio to my xbox 360).
SO I wonder given this information that I would be better getting
asingle 1GB stick and replacing one of the 256 and getting single speed
but more raw memory.

You'd be better off getting rid of Vista and leaving XP on
it. it should stream to one system fine with 256MB
installed.

OR the fact that I am currently using about 480MB and that is about as
high as it needs to go for what it is going to be doing suggests that
1GB is enough.

yes, 1GB is enough, and memory performance doing what is
essentially fileserving over 100Mb lan is inconsequential.
An old Pentium 400 system with 128MB and Win2k could do this
just as well.

 

[jrmwillis]

I am actually running Windows Media Center edition, not just streaming
files. That is why it runs so memory heavy. Vista gives me the best
experience with my xbox 360 as a media center which is why I am using
it. It works very well.

I used to run XP Media Center and it did run fine although I wasn't
using my xbox as an extender.

 

[DaveW]

Do you know if your model of motherboard DEFINITELY supports dual channel
memory? The older DDR motherboards do not.

 

[jrmwillis]

I am 90% sure it does

Do you know if your model of motherboard DEFINITELY supports dual channel
memory? The older DDR motherboards do not.

 

[jrmwillis]

I don't feel like I have the final word on this...

I guess right now I am thinking about going with the 512MB matching
pair.