«

I'm running a Compaq Presario 6000 with 256Mb of RAM - it's in need of more!

Specification I have is 184-pin PC3200 DDR400 CL=3.0 Non-ECC.

Looking a EBay adverts, some are for high-density RAM - will that work?
What's the difference?
--
Budgie
NB Reply to newsgroup. Email address will get you nowhere.

Budgie wrote:
> I'm running a Compaq Presario 6000 with 256Mb of RAM - it's in need of more!
>
> Specification I have is 184-pin PC3200 DDR400 CL=3.0 Non-ECC.
>
> Looking a EBay adverts, some are for high-density RAM - will that work?
> What's the difference?
Good greif!
NEVER buy RAM, hard drives, etc via E-bay unless you do not care
about the provenance and the quality, and get the junk at junk pricing.
Check out PriceWatch.

Budgie wrote:
> I'm running a Compaq Presario 6000 with 256Mb of RAM - it's in need of more!
>
> Specification I have is 184-pin PC3200 DDR400 CL=3.0 Non-ECC.
>
> Looking a EBay adverts, some are for high-density RAM - will that work?
> What's the difference?
Go to Crucial.com and get the correct type. It appears that the DDR400
(PC3200) needs to be low density.
http://www.crucial.com/store/listpar...0processors%29

Budgie wrote:
> I'm running a Compaq Presario 6000 with 256Mb of RAM - it's in need of more!
>
> Specification I have is 184-pin PC3200 DDR400 CL=3.0 Non-ECC.
>
> Looking a EBay adverts, some are for high-density RAM - will that work?
> What's the difference?

The high density RAM in question would probably be 1GB PC3200 DDR.

A "normal density" stick consists of (16) 64Mx8 chips. That forms
two ranks, with one rank per side of the DIMM. Memory arrays are
64 bits wide, to match the width of the DIMM memory bus. Two chip
select signals control the two ranks of memory. Each chip select
has 8 loads on it. Address/command drivers see sixteen loads, so
that part is normal.

A "high density" 1GB stick consists of (16) 128Mx4 chips. That forms
one rank, spanning both sides of the DIMM. It takes all 16 chips, to
make the necessary 64 bit wide array in that case. It is unclear
to me, how the chip select works. Logically, you'd expect one chip
select to drive all sixteen chips. They could also use the two
chip select signals, and have the signals wiggle exactly the same
way, but that requires chipset support for that operating mode.

In any case, the advert for the high density RAM product on Ebay,
will have a list of chipsets that support that kind of memory.
You'll notice Intel chipsets tend to be missing, and if you download
an Intel datasheet, they'll tell you they support x8 and x16 chip
types.

If you buy that Ebay RAM, then it may not be portable between all
of your computers. For example, with the two computers I own that
are worth using, the high density product won't work in one of
them (Intel) and in the other (Nvidia Nforce2), only half of
the stick registers. That is because, I gather, the Nforce2 lacks
enough address bits to drive the "128M" part of the chip. It
can drive a "64M" row and column, but is one bit short for driving
"128M".

So I don't recommend buying 1GB DDR from Ebay. I'm unaware of any
"tricks" for 512MB DDR, and any kind of DDR2 you want to buy is
probably OK as of today.

As the other posters suggest, stick with safe, branded memory. It
will have a warranty. In the case of Crucial, all of the memory
I bought from them is still working. They also have an excellent
sales interface, and they are one of the few retailers I didn't
have to phone and pester.

If the memory industry was an honest one, and had some scruples,
such caution would be unnecessary. But the chip factories are
willing to sell untested or out of spec chips to any third
party who cares to buy them. The third party is then tasked with
testing them. A lot of the cheap memory you find, may be poorly
tested, because with the small profit margin, the only thing they
can cut back on is testing.

The x4 chip type should really only be used on registered DIMMs,
Because in that case, the register chips help drive the extra load,
and the Northbridge doesn't have nearly as much load on it. Registered
DIMMs are typically used on servers.

HTH,
Paul

"Budgie" <> wrote in message
news:Id3bj.15112$...
>
> Looking a EBay adverts, some are for high-density RAM - will that work?
> What's the difference?
> --

Thanks all for the explanations and advice.

I'll steer clear of EBay. Now there's also EBuyer. . .

--
Budgie
NB Reply to newsgroup. Email address will get you nowhere.

Buy it someplace where they are known for quality products and
quality customer service.

I bought my RAM for a similar Compaq HP machine at Fry's.
It worked fine.

Newegg is also a good place.

If you are trying to run that computer with Windows ****yvista, you
will need at least about 2 gigs total.



> I'll steer clear of EBay. Now there's also EBuyer. . .