SDRAM versus DDR

  • Thread starter Thread starter Dave
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Dave

I have got 768 MB of SDRAM (133 MHz) on my system.

If I go to a DDR mobo then how much 3200 DDR-400 would I need to
get to roughly match the performance of the SDRAM?
 
Dave said:
I have got 768 MB of SDRAM (133 MHz) on my system.

If I go to a DDR mobo then how much 3200 DDR-400 would I need to
get to roughly match the performance of the SDRAM?
Click to expand...

Depends on whether the things you do are most
dependent on the RAM speed or the RAM quantity.

If you do things like video editting, the more RAM the better,
even if you have to settle for something a little slower than
PC3200.

If you do mostly gaming (plus trivial stuff like word processing
and web browsing) then 512 MB of low latency PC3200 should do
you very nicely.
 
If you're doing nothing but starting your system and idling after, 256 megs
would be more than enough
 
If you're doing nothing but starting your system and idling after, 256 megs
would be more than enough
Click to expand...

If that's all you're doing, wouldn't a stick, a feather, and a pile of
pebbles be more than enough?
 
Rob Stow said:
Depends on whether the things you do are most
dependent on the RAM speed or the RAM quantity.

If you do things like video editting, the more RAM the better,
even if you have to settle for something a little slower than
PC3200.

If you do mostly gaming (plus trivial stuff like word processing
and web browsing) then 512 MB of low latency PC3200 should do
you very nicely.
Click to expand...

As a general rule, the greater the memory bandwidth, the faster your
code will run. However, it isn't that simple. A lot will depend upon
how well your program utilizes the on-chip caches. Typically, cache
hit ratios are around 90% or better. This means that 9 times out of
10, the data or instruction that you need will be in cache. This is
independent of SDRAM or DDR memory.

Now, if you get a cache miss and have to go to memory, then you will
see the speed of memory. Or, if you are doing a lot of disk intensive
activity, the memory speed could come into play. In any case, it isn't
a 1:1 relationship between memory bandwidth and code execution speed.

arnie
 
Pebbles were a dead end format after PC100 ram. I've seen some systems
with sticks that wouldn't post. Haven't tried feathers; don't have the bucks.
Maybe the next upgrade....

If that's all you're doing, wouldn't a stick, a feather, and a pile of
pebbles be more than enough?
Click to expand...

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256 megs, the minimum for running XP. The new board will so completely
blow away the old board that it will win with both hands tied behind
it's back.

[But, as a practical matter, you should probably get 512 megs of memory.
Even with SDRAM, it's unlikely that the last 256 megs did much for you
anyway.]
 
Video editing is not particularly memory intensive, it's much more CPU
intensive.
 
Barry said:
Video editing is not particularly memory intensive, it's much more CPU
intensive.
Click to expand...

Video editting when you don't have enough RAM to hold
all or at least a large portion of the clip in RAM is a
painful process. A clip doesn't have to be very big
before even 4 GB of RAM is not enough, especially since
you don't work with compressed streams like AVI or MPEG
files - you do your editting and then compress/encode the
final product.

Video encoding/compression, by contrast, needs relatively
little RAM and is more dependent on raw cpu MHz.
 
256 megs, the minimum for running XP. The new board will so completely
blow away the old board that it will win with both hands tied behind
it's back.

[But, as a practical matter, you should probably get 512 megs of memory.
Even with SDRAM, it's unlikely that the last 256 megs did much for you
anyway.]
I have got 768 MB of SDRAM (133 MHz) on my system.

If I go to a DDR mobo then how much 3200 DDR-400 would I need to
get to roughly match the performance of the SDRAM?
Click to expand...
Click to expand...


But you need 2 DDR Rams to get Dual Channel Memory, I would not get a MoBo
that did not support Dual Channel DDR 400 Memory
 
not a fair comparison.

DDR and SDRAM may run at the same speeds, but DDR has double the bandwidth.

So, for the same theoretical throughput.. you could get the same MB/s moved
with 1/2 the amount of DDR.

But thats just dumb...

NuTs
 
dual channel is marketing hype...

Not enought real benefit. To my mind, it would have to be at least 20%
performance increace for me to justify the need to buy 2 sticks. I havent
read anything that suggest that anything more that just over 10% can be had.

NuTs

Dumdedo said:
256 megs, the minimum for running XP. The new board will so completely
blow away the old board that it will win with both hands tied behind
it's back.

[But, as a practical matter, you should probably get 512 megs of memory.
Even with SDRAM, it's unlikely that the last 256 megs did much for you
anyway.]
I have got 768 MB of SDRAM (133 MHz) on my system.

If I go to a DDR mobo then how much 3200 DDR-400 would I need to
get to roughly match the performance of the SDRAM?
Click to expand...
Click to expand...


But you need 2 DDR Rams to get Dual Channel Memory, I would not get a MoBo
that did not support Dual Channel DDR 400 Memory
Click to expand...
 
dual channel is marketing hype...

Not enought real benefit. To my mind, it would have to be at least 20%
performance increace for me to justify the need to buy 2 sticks. I havent
read anything that suggest that anything more that just over 10% can be had.

NuTs
Click to expand...



No its not, the Memory bench mark I get is some 80% faster..

Also it been posted that it far wiser to get 2 sticka, as if one fails you
can still use the other.

Dumdedo said:
256 megs, the minimum for running XP. The new board will so completely
blow away the old board that it will win with both hands tied behind
it's back.

[But, as a practical matter, you should probably get 512 megs of memory.
Even with SDRAM, it's unlikely that the last 256 megs did much for you
anyway.]

Dave wrote:
I have got 768 MB of SDRAM (133 MHz) on my system.

If I go to a DDR mobo then how much 3200 DDR-400 would I need to
get to roughly match the performance of the SDRAM?
Click to expand...


But you need 2 DDR Rams to get Dual Channel Memory, I would not get a MoBo
that did not support Dual Channel DDR 400 Memory
Click to expand...
Click to expand...
 
Dumdedo said:
But you need 2 DDR Rams to get Dual Channel Memory, I would
not get a MoBo that did not support Dual Channel DDR 400
Memory
Click to expand...


I read somewhere that the performance improvement (for non gamers)
of dual DDR was very small indeed. Is that misleading?
 
Dumdedo said:
No its not, the Memory bench mark I get is some 80% faster..
Click to expand...

Have you got a link to this please.

Also it been posted that it far wiser to get 2 sticka, as if
one fails you can still use the other.
Click to expand...

I thought you *had* to have two sticks in order to implement dual
channel memory. Is this not so?
 
I read somewhere that the performance improvement (for non gamers)
of dual DDR was very small indeed. Is that misleading?
Click to expand...

It's not much even for gamers. Typically less than 10%. unless it's also
serving as the frame buffer for integrated video.
 
Rob Stow has a great answer here. I'd listen to him.
Knowing what XP likes to have, memory-wise, and seeing applications only
becoming more memory-intensive, if I were you I would get two sticks of 512
meg each. If you can't afford that much right now, get one at a time. A gig
of RAM is a great all-purpose amount. However, like was mentioned, if you do
something like video editing, you almost can't have enough RAM.
 
NuT said:
dual channel is marketing hype...

Not enought real benefit. To my mind, it would have to be at least 20%
performance increace for me to justify the need to buy 2 sticks. I havent
read anything that suggest that anything more that just over 10% can be had.
Click to expand...

You can view that differently: if you get a P4 3.4Ghz this will be 6%
faster at maximum than a P4 3.2Ghz, yet people buy that even if it costs
150USD or so more (not me, of course ;-)). Dual channel memory which
likely offers a higher performance increase overall is thus a bargain,
as 2 256MB modules hardly cost more than 1 512MB module (not to mention
if you want 1GB, you'd need 2 modules anyway unless you want to buy the
really expensive 1GB modules).
I'd agree though dual channel memory is a waste on Athlon XP systems,
the performance increase is pretty much non-existant (except synthetic
measurements below 2% or so), unless you use the integrated graphics on
a board.

Roland
 
kony said:
It's not much even for gamers. Typically less than 10%. unless it's also
serving as the frame buffer for integrated video.
Click to expand...


This guy just nailed it. Plain and simple, dual-channel is best suited with
onboard graphics. We all know onboard graphics can't compete.
 
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