Question about RDRAM

[TAB]

Hi, I am contemplating the purchase of a used system for a very cheap
price (around 130$) made by Gateway. It is a P4 1.3 GHZ machine with
128 megs of RDRAM.

I was concerned about the RDDRAM. The specs say it uses an 800mhz
RDDRAM chip. I understand these have to be installed in pairs. So if I
wanted 256megs, that means I must buy two 128 meg chips, which seem to
be quite overpriced, and crucial didnt' seem to carry them.

Looking on another site I find information about a CRIMM. If I
understand correctly, you can use a CRIMM in one slot, and a Ram chip
in another.

This is what I want to know - can you get (1) RDRAM 256 chip and
(1)CRIMM and that be all - and this work?

Thanks for educating me . . .

-TB

 

[Tony Hill]

Hi, I am contemplating the purchase of a used system for a very cheap
price (around 130$) made by Gateway. It is a P4 1.3 GHZ machine with
128 megs of RDRAM.

I was concerned about the RDDRAM. The specs say it uses an 800mhz
RDDRAM chip. I understand these have to be installed in pairs.

This is true.

So if I
wanted 256megs, that means I must buy two 128 meg chips

You could upgrade the system by buying 2x64MB RIMMs. Presumably the
current system already has 2x64MB in there and almost all RDRAM P4
systems have 4 RIMM sockets (note: I have no idea about the specifics
of this Gateway system, it could be the exception to the above rule,
though I would doubt it).

, which seem to
be quite overpriced, and crucial didnt' seem to carry them.

Crucial is Micron's retail front-end. Micron and Rambus have been in
a rather lengthy court battle for the past few years. I don't expect
that Crucial will ever carry any RDRAM!

Looking on another site I find information about a CRIMM. If I
understand correctly, you can use a CRIMM in one slot, and a Ram chip
in another.

You MUST put CRIMMs in any slots that are not being used. The current
system most likely has 2x64MB in two of the sockets and 2 CRIMMs in
the other two sockets.

This is what I want to know - can you get (1) RDRAM 256 chip and
(1)CRIMM and that be all - and this work?

Nope, no can do. You need matched modules in each of the two
channels. If you put a 128MB module in one, you need to put a 128MB
in the other. Each channel has two sockets, and you can have
different modules in the two sockets of the same channel, but the both
sockets in one channel must match both sockets in the other channel.
So, you can have 2x128MB + 2xCRIMMs, or you can have 2x64MB + 2x64MB,
but there is no way to have just a single module on it's own.

In any case, if you go to www.memman.com, they sell 2x128MB RDRAM kits
for $99 to $116, depending on just what type of module you need. They
also have the same sort of memory configurator that Crucial has, ie
you plug in the make and model of your system and it spits out the
memory that will work with it. Kingston's Valueram (www.valueram.com)
also sells RDRAM for similar prices, though the smallest models they
sell are 256MB. In any case, RDRAM is more than DDR memory and the
performance isn't really any better (though back in the day when the
P4 1.3GHz came out RDRAM was a LOT better for it than the PC133 SDRAM
around then), but if the total system price works out ok then it might
not be too bad.

FWIW, If you do go for this system I would recommend that you buy all
the RDRAM you think this system is ever going to need now, because
it's almost certainly not going to get any cheaper.

 

[David Wang]

Looking on another site I find information about a CRIMM. If I
understand correctly, you can use a CRIMM in one slot, and a Ram chip
in another.

Not quite. The RIMMs are paired. You can use CRIMMs in paired
slots or not at all, populate the board with paired RIMMs.

This is what I want to know - can you get (1) RDRAM 256 chip and
(1)CRIMM and that be all - and this work?

No. This won't work. There are a total of 4 RIMM slots. You likely
have 2 64 MB RIMMs and 2 CRIMMs in there. You need to yank out the
2 CRIMMs and replace them with a pair of 64 MB or a pair of 128 MB
RIMMs.

 

[RusH]

(e-mail address removed) (TAB) wrote in

Hi, I am contemplating the purchase of a used system for a very
cheap price (around 130$) made by Gateway. It is a P4 1.3 GHZ
machine with 128 megs of RDRAM.

[cut]

dont do it, P4 1.3GHz is a POS and nothing will change that. Celeron
1GHz is plenty faster.

Pozdrawiam.

 

[Martin Basil]

Hi, I am contemplating the purchase of a used system for a very cheap
price (around 130$) made by Gateway. It is a P4 1.3 GHZ machine with
128 megs of RDRAM.

I was concerned about the RDDRAM. The specs say it uses an 800mhz
RDDRAM chip. I understand these have to be installed in pairs. So if I
wanted 256megs, that means I must buy two 128 meg chips, which seem to
be quite overpriced, and crucial didnt' seem to carry them.

Looking on another site I find information about a CRIMM. If I
understand correctly, you can use a CRIMM in one slot, and a Ram chip
in another.

I recently upgraded a Gateway P4 1.7Ghz by adding 2 x 256Mbyte non-ECC RDRAM
P800 to the 2 x 128Mbyte. They have to be identical pairs of the same speed
and type ie P800 non ECC in my case. All worked fine but it cost £110
(nearly $200) and that was the cheapest and took some finding, most other
suppliers where looking for $300+. If would recommend avoiding RDRAM due to
the high cost. It would probably be cheaper to upgrade the motherboard as
you will also be stuck with Socket 473 CPU which has little scope for
upgrade then only to 2Ghz.

Martin

 

[Dale Pontius]

Hi, I am contemplating the purchase of a used system for a very cheap
price (around 130$) made by Gateway. It is a P4 1.3 GHZ machine with
128 megs of RDRAM.

I was concerned about the RDDRAM. The specs say it uses an 800mhz
RDDRAM chip. I understand these have to be installed in pairs. So if I
wanted 256megs, that means I must buy two 128 meg chips, which seem to
be quite overpriced, and crucial didnt' seem to carry them.

Looking on another site I find information about a CRIMM. If I
understand correctly, you can use a CRIMM in one slot, and a Ram chip
in another.

This is what I want to know - can you get (1) RDRAM 256 chip and
(1)CRIMM and that be all - and this work?

Thanks for educating me . . .

Just for jollies, and since nobody else mentioned it...
CRIMM stands for Continuity RIMM. On the RIMM, the packet bus enters
on one side and leaves on the other. This is how they controlled
stubs. As a result, the bus goes through the RIMM, instead of the
way a DIMM taps off of the bus as it goes past. Therefore, RIMM
sockets can't be left empty, hence the CRIMM.

Incidentally, in the early Rambus days, there was the 820 chipset
for single-channel, and the 840 chipset for dual-channel. The 820
went nowhere fast, (600 or 800mpbs, to be precise) and the 840 and
its followons required everything CRIMMs and RIMMs to be installed
in pairs. (Gotta fill both channels)

Dale Pontius

 

[lyon_wonder]

Hi, I am contemplating the purchase of a used system for a very cheap

price (around 130$) made by Gateway. It is a P4 1.3 GHZ machine with
128 megs of RDRAM.

A second-hand P3/Celeron or Athlon system would be better deal since
SDRAM is still cheaper than RDRAM. For the money needed to pay for
the RDRAM you could probably build yourself a cheap Duron or low-end
AthlonXP system.

 

[TAB]

Thanks for everyone's advice. Believe it or not, I bought the machine,
and as you said I found that the RDRAM was way too much, and as
someone else mentioned, I wasn't too impressed with the performance. I
put an ad on a local board and sold it for 200$ (quite more than I
paid for it), and sold my old Celeron system for 100$ and got me a
Shuttle AMD barebone, a 1.8 Duron Processor, 256 megs of DDR 2700,
reused a 40 gb harddrive I already had, and got a low profile gforce 4
agp card. Much happier.