[mythtv-users] OT: Dual Channel DDR

dustymugs at skewedperception.com dustymugs at skewedperception.com
Sat Dec 18 22:04:30 UTC 2004

Tell us what motherboard and CPU you are planning on using.  THe key rule
is  to find a balance between the speed of the ram, speed of the fsb to
the cpu and CAS Latency.

Lets look at 3 Kingston RAM chips from newegg.  This is just a
representativeness of what is out there, I'm not recommending these sticks
or the retailer.


All three rams linked above are DDR400 (PC3200).  But the key difference
between them all is CAS Latency, link a = 3.0, link b = 2.5, link c = 2. 
We can expect c to be faster than b and b to be faster than a.  But more
importantly, is the speed gained worth the difference in price?  Thats for
you to decide.  Also, that ram sink in link c isn't for function, its for
show.  If it actually were for function, servers would be using RAM with
heatspreaders.  Take a peak into any top of the line Dell, IBM, HP box and
you'll notice that the ram found there do not have ramsinks or any other

My Recommendations...

1.  You're getting a 800 MHz FSB P4 CPU (or 400 FSB AMD CPU) with a
matching motherboard: All three ram sticks linked above with work, and
work well but just speed difference c > b > a.  If its for a mythtv box,
i'd recommend going for a or b if you feel like sparing the cash.  If for
gaming and NO overclocking, get a, you'll want the 5 fps gained (LOL
though you'll probably not notice anyways).  If you plan on overclocking,
you'll need something better than link a.  You'll want to get something
that does at least DDR466 (PC3700) but it'll cost an arm and a leg.

2. You're getting a 533 or 400 MHz FSB P4/Celeron CPU (or 333 or 266 FSB
AMD CPU): Again, all three ram sticks will work.  Link c is kinda
overkill.  Link b isn't overkill but it ain't bang for your bucks.  Link a
is probably the best buy.  Why?  The ram is set for running at 800 MHz but
your cpu ain't (unless you plan on overclocking) and CAS Latency 3.  So,
this means you can bump the speed setting of the ram down and adjust the
CAS Latency and other ram settings.  Example, you bump the ram down to 400
MHz if you have a 400 MHz CPU and you can probably set your other RAM
setting more aggresively with CAS Latency at 2.  To get an idea of what
your ram is capable, i've always used a program called CPU-Z to see what
the ram can do (find it on google).  In doing so, your ram will run faster
than it would stock and you saved quite a bit of cash.  (Actually this is
what i do with my several 533 P4 and Celeron setups.  I buy the equivalent
of link a and tweak the ram, though i bought cheaper ram, my speed is

Jeez, that was a long message.  Hope that makes sense.


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