[MEncoder-users] Do RAM memory timings matter ?

Vladimir Mosgalin mosgalin at VM10124.spb.edu
Mon Mar 20 19:27:45 CET 2006

Hi dusty0 at freemail.gr!

 On 2006.03.20 at 18:28:11 +0200, dusty0 at freemail.gr wrote next:

> Do RAM memory timings matter when encoding or even decoding video ?  I

They always do, since memory is quite slow compared to cpu, and they
play a very big role on A64 systems, however..

> use 2GB(2x1GB) of RAM  2.5-4-4-8 and I was wondering if it is better
> to have 2x1GB 3-3-3-8 timings..

3-3-3 isn't always better than 2.5-4-4. It's true that CL (first number)
doesn't matter that much on A64, but you know, overal difference would
be too small.
And FYI, -8 (TRas) doesn't matter at all. Also, often the best value for
it isn't maximum or minimum, but something in 9-11 range.

You should take a note of another memory timing, called "DRAM Command"
or something like that (1T/2T). Setting it to 1T (if your memory can
take it) gives performance boost in some applications.

In practice, you'll notice the difference between slow vs fast memory,
like DDR400 3-3-3 vs DDR400 2-2-2 or DDR533 2.5-3-3, however for mplayer
I don't think even that matters. When decoding, cpu-hungry filters like
spp or pp7 work entirely within the cpu cache, so memory timings won't
matter at all. Not sure about encoding, but this can also be the case.

Anyway, if you are interested in this subject, read articles on
http://www.extremeoverclocking.com/ or similar sites (this one is quite
good, though). Also people in forums there will be able to answer such
questions in more detail than here, even if it's mplayer-related...

> I am on AMD64 X2 (running both 32bit and 64bit Linux) and I wan't to
> take the 100% of my system ;-)

Well you'll be disappointed by the fact that mplayer doesn't support HT,
multicore cpus and so on. So for example if you have A64 X2 3800+, think
of it as of A64 3000+ when it comes to mplayer ;)



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