Memory speed question

  • Thread starter Thread starter Wolf Kirchmeir
  • Start date Start date
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Wolf Kirchmeir

Hi,

I have purchased two 533MHz 1GB SODIMMs for my wife's laptop (it came
with 512MB). On checking specs (which I should have down first, silly
me) I find that the machine uses 667MHz SODIMM.

Question:
Will the system recognise and work with 533MHz SODIMMs?

Thanks.
 
Wolf said:
Hi,

I have purchased two 533MHz 1GB SODIMMs for my wife's laptop (it came
with 512MB). On checking specs (which I should have down first, silly
me) I find that the machine uses 667MHz SODIMM.

Question:
Will the system recognise and work with 533MHz SODIMMs?

Thanks.
Click to expand...

Silly you, if you'd included the make and model number of the laptop
in your posting, we could look it up on Crucial.com or Kingston.com .

Generally speaking, modern chipsets decouple memory interfaces from FSB,
allowing then to run at different speeds. So there shouldn't be
a problem. Older chipsets either operated synchronously, or had
limited asynchronous settings (for example, one chipset enforced
synchronous operation, at the highest FSB setting). Generally,
anything with DDR2 in it, should be more flexible. But looking
up the memory requirements (or looking in the manual), will
give you some ideas.

Here is an example, comparing a couple Intel DDR2 mobile chipsets.
Note that DDR2-533 and DDR2-667 are supported.

http://compare.intel.com/pcc/showchart.aspx?mmID=28117,28116&familyID=7&culture=en-US

Every chipset could be different, which is why knowing the make
and model would be important. This SIS chipset supports DDR2-400,
DDR2-533, and DDR2-667.

http://www.sis.com/products/sism672mx_features.htm

Paul
 
Paul said:
Silly you, if you'd included the make and model number of the laptop
in your posting, we could look it up on Crucial.com or Kingston.com .
Click to expand...

Acer Travelmate 4202WLMi, w/ 512MB DDR-2 RAM. Can support up to 2GB.

[...]
Thanks for your comments, they reminded me to check the system specs
more thoroughly. I used SANDRA, which reported that the memory bus speed
was 528MHz, and its maximum speed 668MHz. Hence the reference to 667MHz
memory that turned up somewhere and cause me some minor conniptions.
(BTW, Acer's online info is scanty, to put it mildly.)

It looks like the machine will be quite happy with 533MHz memory.

Thanks for your help.
 
DaveW said:
Yes, but the system will run slower. Is that OK with her?
Click to expand...


Thanks, but the constant disk activity with 512MB is a major slowdown.
In effect, the machine was capable of running only one application at a
time. Bah! I'll be installing 2GB, so I expect the actual speed to be
much, much faster. Besides, the memory bus speed is spec'ed at 528MHz,
max speed is 668 MHz, and AFAIK, a system won't reach max memory speed
all that often. So my wife should see a major improvement. Which will
make her happy. ;-)
 
in message
Paul said:
Silly you, if you'd included the make and model number of the
laptop
in your posting, we could look it up on Crucial.com or Kingston.com
.
Click to expand...

Acer Travelmate 4202WLMi, w/ 512MB DDR-2 RAM. Can support up to 2GB.

[...]
Thanks for your comments, they reminded me to check the system specs
more thoroughly. I used SANDRA, which reported that the memory bus
speed was 528MHz, and its maximum speed 668MHz. Hence the reference
to 667MHz memory that turned up somewhere and cause me some minor
conniptions. (BTW, Acer's online info is scanty, to put it mildly.)

It looks like the machine will be quite happy with 533MHz memory.
Click to expand...

But will your wife be happy when you end up significantly slowing her
laptop by using slower memory. The laptop won't make you sleep on the
sofa.
 
VanguardLH said:
in message
Paul said:
Wolf Kirchmeir wrote:

I have purchased two 533MHz 1GB SODIMMs for my wife's laptop (it
came with 512MB). On checking specs (which I should have down first,
silly me) I find that the machine uses 667MHz SODIMM.

Question:
Will the system recognise and work with 533MHz SODIMMs?

Silly you, if you'd included the make and model number of the laptop
in your posting, we could look it up on Crucial.com or Kingston.com .
Click to expand...

Acer Travelmate 4202WLMi, w/ 512MB DDR-2 RAM. Can support up to 2GB.

[...]
Thanks for your comments, they reminded me to check the system specs
more thoroughly. I used SANDRA, which reported that the memory bus
speed was 528MHz, and its maximum speed 668MHz. Hence the reference to
667MHz memory that turned up somewhere and cause me some minor
conniptions. (BTW, Acer's online info is scanty, to put it mildly.)

It looks like the machine will be quite happy with 533MHz memory.
Click to expand...

But will your wife be happy when you end up significantly slowing her
laptop by using slower memory. The laptop won't make you sleep on the
sofa.
Click to expand...

She'll never notice. Especially if Sandra is reporting that the current
memory is DDR2-533.

Paul
 
Paul said:
VanguardLH said:
in message
Paul wrote:

Wolf Kirchmeir wrote:

I have purchased two 533MHz 1GB SODIMMs for my wife's laptop (it
came with 512MB). On checking specs (which I should have down
first, silly me) I find that the machine uses 667MHz SODIMM.

Question:
Will the system recognise and work with 533MHz SODIMMs?

Silly you, if you'd included the make and model number of the laptop
in your posting, we could look it up on Crucial.com or Kingston.com .

Acer Travelmate 4202WLMi, w/ 512MB DDR-2 RAM. Can support up to 2GB.

[...]
Thanks for your comments, they reminded me to check the system specs
more thoroughly. I used SANDRA, which reported that the memory bus
speed was 528MHz, and its maximum speed 668MHz. Hence the reference
to 667MHz memory that turned up somewhere and cause me some minor
conniptions. (BTW, Acer's online info is scanty, to put it mildly.)

It looks like the machine will be quite happy with 533MHz memory.
Click to expand...

But will your wife be happy when you end up significantly slowing her
laptop by using slower memory. The laptop won't make you sleep on the
sofa.
Click to expand...

She'll never notice. Especially if Sandra is reporting that the current
memory is DDR2-533.

Paul
Click to expand...

a) I installed the 2GB of 533MHz DDR2, and the machine no longer
thrashes the HDD trying to run two or more programs simultaneously. IOW,
apparent speed is much, much faster, which is what counts.

b) 667MHs is about 25% faster than 533 MHz. I've read many, many reviews
comparing machines with different speeds in different parts of their
anatomy, and I've never seen actual speed differentials that bore any
resemblance to those hardware differences. I didn't time the original
config, but I suspect that there will be at most a 10% hit in actual
performance. Not noticeable "in ordinary use".

Thanks for your help, which made me feel comfortable about installing
the slower RAM, and your kind comments.
 
Wolf said:
Paul said:
VanguardLH said:
in message
Paul wrote:

Wolf Kirchmeir wrote:

I have purchased two 533MHz 1GB SODIMMs for my wife's laptop (it
came with 512MB). On checking specs (which I should have down
first, silly me) I find that the machine uses 667MHz SODIMM.

Question:
Will the system recognise and work with 533MHz SODIMMs?

Silly you, if you'd included the make and model number of the laptop
in your posting, we could look it up on Crucial.com or Kingston.com .

Acer Travelmate 4202WLMi, w/ 512MB DDR-2 RAM. Can support up to 2GB.

[...]
Thanks for your comments, they reminded me to check the system specs
more thoroughly. I used SANDRA, which reported that the memory bus
speed was 528MHz, and its maximum speed 668MHz. Hence the reference
to 667MHz memory that turned up somewhere and cause me some minor
conniptions. (BTW, Acer's online info is scanty, to put it mildly.)

It looks like the machine will be quite happy with 533MHz memory.

But will your wife be happy when you end up significantly slowing her
laptop by using slower memory. The laptop won't make you sleep on
the sofa.
Click to expand...

She'll never notice. Especially if Sandra is reporting that the current
memory is DDR2-533.

Paul
Click to expand...

a) I installed the 2GB of 533MHz DDR2, and the machine no longer
thrashes the HDD trying to run two or more programs simultaneously. IOW,
apparent speed is much, much faster, which is what counts.

b) 667MHs is about 25% faster than 533 MHz. I've read many, many reviews
comparing machines with different speeds in different parts of their
anatomy, and I've never seen actual speed differentials that bore any
resemblance to those hardware differences. I didn't time the original
config, but I suspect that there will be at most a 10% hit in actual
performance. Not noticeable "in ordinary use".

Thanks for your help, which made me feel comfortable about installing
the slower RAM, and your kind comments.
Click to expand...

Look at how small the difference is, in the SuperPI benchmark
on this page, between DDR2-533 and DDR2-667. 85.3 seconds execution
time, versus 84.7 seconds. You'd need a stopwatch to spot that
difference, and very good reflexes.

http://www.anandtech.com/memory/showdoc.aspx?i=2732&p=4

Paul
 
Silly you, if you'd included the make and model number of the laptop
in your posting, we could look it up on Crucial.com or Kingston.com .

Generally speaking, modern chipsets decouple memory interfaces from FSB,
allowing then to run at different speeds. So there shouldn't be
a problem. Older chipsets either operated synchronously, or had
limited asynchronous settings (for example, one chipset enforced
synchronous operation, at the highest FSB setting). Generally,
anything with DDR2 in it, should be more flexible. But looking
up the memory requirements (or looking in the manual), will
give you some ideas.

Here is an example, comparing a couple Intel DDR2 mobile chipsets.
Note that DDR2-533 and DDR2-667 are supported.

http://compare.intel.com/pcc/showchart.aspx?mmID=28117,28116&familyID...

Every chipset could be different, which is why knowing the make
and model would be important. This SIS chipset supports DDR2-400,
DDR2-533, and DDR2-667.

http://www.sis.com/products/sism672mx_features.htm

Paul
Click to expand...

can you give an example of a chipset and mbrd that isn't regular like
that? it'd be interesting also 'cos i'd check the mbrd manual and see
pics of the BIOS screen

i.e. regular case is where higher speed ram works at lower speed and
lower speed ram works at that speed. 'cos stock speed is just max
speed it has been tested to run stably at. It can stably run lower,
and it can run higher, possibly stably.
so which chipset and mbrd is irregular ?

infact, in my understanding, when you overclock or underclock the RAM.
you're actually changing the clock speed of the memory bus - which is
on the mbrd. And from the BIOS you can set the memory bus speed. Would
that be right?

So what would the S mean in Synchronous for SDRAM ? I had thought it
meant it had its own clock
 
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