Question about DDR2

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Hi All (though there doesn't seem to be too many posters to this group

 I have a cheap ECS RC410L motherboard and a Pentium D 805.   This combo
will run 3.5Ghz overclocked...but for some reason its not perfectly will
boot and run Prime 95 (two instances) fine for hours...but when I stop the
of Prime 95 it crashes.  It will run for hours and then all of a sudden I
get a BSOD.
I'm guessing this is somewhat a heat problem.  I'm using stock cooling which
isn't that great.

I am also guessing that its a memory problem.

The memory it uses is DDR2-667...which should be able to run stable using a
of 166MHz or abouts?   Its seems that this motherboard overclocked is stable
at 166FSB
but not very much higher.

Am I correct in believing that this DDR2 is only rated to FSB166 Mhz?   Or
can it be
run higher?   I tried  a DDR2-800 stick of RAM in this mobo but it wouldn't
even boot.
Presumably this mobo doesn't take DDR2-800...but isn't that what would be
to run the system reliably at 200FSB?  That would be needed to run these
Pentium D 805s
at 4Ghz if possible?  And would an enhanced CAS timing module help me
achieve a higher reliable
FSB.  I'm confused a little bit...any help would be appreciated.

Re: Question about DDR2

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Remember that an 805 draws a fair bit of power when it is
overclocked. It could be that the Vcore voltage regulator
on the ECS board has a problem with transient response (when
the load goes from high current, when Prime95 is running, to
low current, when you stop). Use your fingers, and probe
around the Vcore components after a Prime95 session - if you
burn yourself, that would hint at being past the limits of
reasonable operation of the RC410L. (Your motherboard has a
three phase regulator, but the MOSFETs appear to be standing
up, and without heatsinks. That is a recipe for trouble, in
terms of keeping the MOSFETs cool. At high overclock, you
could be asking that poor circuit to provide 165W.)

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The ECS manual is decidedly unhelpful (and a porker at 13MB).
It seems to have an adjustment for the CPU FSB, but it doesn't
state what ratios are used between the CPU and memory clock.
The memory clock does not appear to be adjustable. The ECS
manual shows as an example, in the BIOS section of the manual,
FSB800 operation with the memory running at 266MHz (I guess DDR2-533).

So, that says it doesn't have to run sync. I would guess that
the BIOS is able to read the SPD on the DIMM and adjust the
memory clock independent of the FSB. The manual states that
DDR2 667/533/400 can be used, and the BIOS could be adjusting
the clock according to the DIMM rating. Now, if there was a
fixed divider at work, then either the BIOS will downclock the
memory, once you get past a certain level of overclock,
or it would end up doing something really stupid, which
is overclocking the memory with the slightest CPU overclock.

I think you need to get a copy of CPUZ. Start your 805 at
stock (133MHz for FSB533). Use CPUZ to see what memory
frequency and timings are used. Increase the CPU clock so
that the FSB goes faster. Watch what happens to the memory
clock. Maybe the BIOS display screen is reliable enough, to
actually trust the memory clock shown on the screen, as you
adjust the CPU clock. Or maybe the BIOS is really stupid and
lies to you. CPUZ is like truth serum, and when you use
CPUZ, it will tell you what is really going on. Collect
your results on some notepaper, noting the memory clock
choice as you go from FSB533 to FSB700 (my guess as to how
you got to 3.5GHz). If the recorded values of the memory
clock, go faster than the rating of the memory (>333Mhz for
DDR2-667), then the memory is being overclocked. You would
want the tiny DDR memory voltage boost to be enabled, if
that is the case. Chances are the memory needs more voltage
than the ECS board can deliver, to overclock very high.

As for your DDR2-800 experiment, the BIOS probably decided
that 800 > 667, and threw in the towel. Not smart enough
to just run it at DDR2-667, as you would expect.

So the only way to answer your question, is to experiment.
You should be able to spot the trend pretty quick.


Re: Question about DDR2

On Sun, 25 Jun 2006 07:33:32 GMT, "Don W. McCollough"

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I have the same motherboard and cpu, purchased at Fry's a few weeks
ago.  I purchased a relatively inexpensive HSF (CoolerMaster) from
Newegg for $15, and mine is running stable at 20 x 166 mhz
(approximately 3.3 ghz).  I have successfully run Prime95 (two
instances) for one hour at 20 x 175 (3.5 ghz), but I am running at 3.3
ghz as I prefer the lower temperatures.  For some reason, cpuz will
not tell you the memory speed on this motherboard.  However, judging
from the memory throughput numbers shown by memtest, the memory is
locked to the default value and does not change as you increase the
FSB from 133 all the way to 175.

My motherboard is not stable with two sticks of memory, I have tried
two different pairs of PC2-5300 memory (2 x 512).  All four sticks are
stable when run individually, but not when run as pairs.  I gave up
and purchased a single 1 gig stick of memory to use in the

Using the retail Intel HSF, I was hitting 72 degrees centigrade under
full cpu load at 20 x 150 (3 ghz).  With the CoolerMaster, at 3.3 ghz
under full load, I am running about 65 degrees centigrade.

The built in ATI graphics seem fairly good (I am not a gamer), and
overall I am well pleased with this combo for the price.  ($149 when I
purchased a few weeks ago, $129 in the latest Fry's ads).

Re: Question about DDR2

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I'm in the same boat.  3.3Ghz runs all day stable.   I was just curious
whether mine was a limitation of memory (4x166Mhz FSB) (DDR2-667) or
else.  CPU-Z wont give me info on my memory, but I use Roadkil's CPUID
and my computer is stable at 660Mhz FSB (4x166Mhz) which would be
within the memory's specification.   I can overclock to 3.5Ghz, but the
become unstable.   I believe these chips will do more than that.  Either the
CPU power supply is weak, or perhaps the power supply I'm using is weak.
( I doubt it )

I bought one of these monster coolers from last yesterday.

$21 bucks.   I will see if the cooler makes any difference.  The stock
cooler that comes with it seems a little weak.

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