kony wrote

Budget memory is not supposed to be able to run the FAST timings,
that's WHY it's budget memory.

Then why did even cheaper K-byte and no-name Fry's memory work fine
that way? Some of the Fry's memory I've gotten has been really
questionable, but so far, all the DDR modules have tested OK.

Some may work fine because that's the situation with budget memory,
some of the chips are actually capable of higher, tigher timings than
others. It is only guaranteed to work at default SPD timings in a
motherboard conforming to spec as well. If the motherboard isn't
within spec, it may require higher quality memory... this is also a
known problem with ALL nForce2 boards.

My boards are SiS 735 and 645, and I tried not only SPD timings but
slower ones, too. I think that some of the Kingston ValueRAM didn't
work because Kingston, in an effort to cut costs, lowered the margin
of safety of their memory.

It could be that you just happened upon a bad module... it happens,
obviously it's not cost-effective for a manufacturer to do as much
testing on very cheap memory.

I can understand one bad module (none seemed to have been returned by
other customers), but two in a row, separated by several months, one
soldered in China, the other in the US? I also had two bad
K-byte/Spectec modules in a row.

it does sound like you did all the testing possible on that
board, but it doesn't rule out the board itself.

True, but I also tested the first and second modules with two K7S5A
boards (not K7S5A Pro) that didnt' belong to me, and they acted the
same -- the oldest was fine, the newer one failed at the same address
and with the same bits. These boards use the same SiS 735 chipset but
had different BIOSes, and there have been hardware tweaks made with
the K7S5A.

Of the low-end modules, the ones I see with the least headroom for
MHz for timing increase are those with the cheaper PCB including
film resistors, not surface-mount parts, like this (thought it's of
a PNY PC2100 module): http://69.36.189.159/usr_1034/pny-resistors.jpg

All the other Kingston PC2100 modules I've tried will do at least
166MHz @ 2.5,3,3,6 except for one that can only do ~ 145 or so,
providing only 1 or two modules are used. That is in multiple
motherboards of Via, Sis, and nForce chipsets.

I have a "free" Fry's PC133 with film resistors, but all three
versions of the Kingston DDR modules had identical circuit boards with
surface mount resistors.

Unfortunately it's unlikely that you were speaking to anyone with
enough technical background to help unless they forwarded the call a
couple times, most likely you know a lot more about the issues than
whoever you were talking to.

They forwarded my call only once, to "second level tech support," but
a few months ago I was forwarded a couple of times, but nobody ever
gave me specifics.

The only memory modules that showed errors with these mobos were
K-byte with Spectec chips and later Kingstons. These are obviously
not prime memory modules because their chips are not labelled with
the chip manufacturer's standard part numbers but are either used or
second grade.

What were the numbers on the chips? I may have some, or a different
lot... all of those I have/had will do up to ~147Mhz, usually quite a
bit higher. I'm not surprised that they're not "prime" though, given
the low price. On the other hand I still think the motherboard is
playing a crucial role in the instability.

All the Kingston DDR chips had only "32M x 8 - 7 - l" printed on them,
usually very faintly (invisible except at an angle), but they were
bright on the oldest module (the one that worked fine). The Spectec
and Elixir chips had numbers that at least looked like something put
on by chip manufacturers, the Elixers' being N2DS12H80AT-75B
201Y0XSY.

The green-with-silver Luxons are "supposed" to be Low-ESR, they're
what's used in circuits clearly needing low-ESR caps, like for the
switching regulation of the CPU. I'm sure that at least one K7S5A
I've had, did have those green/silver Luxons there as well as around
the memory. I've seen Ost caps fail too, but not in large enough
numbers to draw a conclusion about 'em.

Well, actually I do recall having to replace about 9 of the
green/silver Luxons around the regulators on a K7S5A because they
vented... dead board... works fine now at 150MHz FSB with ??? (I
forget, some nearly FAR memory).

On my K7S5A Pro and P4S5A, the 3-phase voltage regulator has several
purple/gold Ost brand capacitors around it, with only a couple of
green/silver Luxons. The other voltage regulators, which seem to be
the linear type because I didn't see any coils near them, have mostly
black/white and green/silver Luxons. I may just get replacements the
next time I order a bunch of capacitors
from Mouser or Digi-Key since it's easier and cheaper to replace caps
than transistors and diodes.