Dell 8100 and RAMBUS! Must be installed in pairs, RIGHT?

[brian_riendeau]

Ok, I am sitting in a Dell training class right now. There is a schmuck behind me trying to say that you can install a SINGLE 128MB stick of RDRAM into a Dimension 8100 and combine it with THREE other 32MB sticks of RDRAM, and have it work correctly. The guy even claims that his personal system runs off a single stick of RDRAM.

Now, this actually turned into a full blown argument since the guy won't give up and keeps saying that you DON'T need to install RAMBUS in pairs. Can anyone provide me with more info on this? It does not even need to be about the Dimension 8100 systems, just general RAMBUS info about having to install it in pairs. Maybe some tech docs on RAMBUS or something similar? THANKS!!!

 

[Big Lar]

Depends on the chipset of the board, the 850 Intel chipset Will Not run in unmatched pairs/ that much I know, the 840 does tho.

 

[jaredm77]

I've always heard that Rambus must be installed in identical pairs, like (64 and 64=128, 128+128=256, etc.) That's why you don't hear of P4 system with 64MB or 192MB of RAM.

 

[eviltoon]

Dell sure do sell them in matching pairs. I know that you have to have a pair slotted, the only vague point is whether they "have" to be matching. Dell gave them to me matched, and I upgraded with matching pairs. Don't you just hate boneheads that argue a point until they're dead. Hey, when you find out for sure, let us know. Personally, I'd bet money on the exacting pair. Hope you can put this guy in his place.

 

[jlarsson]

I own a Dell Dimension 8100. Since it uses the 850 chipset, rdram must be installed in pairs. If you go to Dells website, it has this information on its support page. My system came w/128 mb pc800 memory,(2 * 64mb occupying the first 2 rimm slots). I have since added an additional 256mb (2 * 128mb rimms).

 

[Noriaki]

The i840 and i850 are dual channel Rambus, they must be installed in pairs. The i820 is single channel and can be installed singly.

I'm not 100% certain on Dell numbers, but I believe the I8100 is a Pentium4 system, thus i850, thus RDRAM needs to be installed in pairs.

 

[tigerbait]

<< I've always heard that Rambus must be installed in identical pairs >>




Not all Rambus. On my VC820 motherboard, you only need one RIMM and a continuity module. But for 850 or 840, which are dual channel, you need to install in pairs.

 

[shathal]

Yup, Tigerbait got it in one.

Depending on how many memory channels you have (1 channel == 2 RIMM slots), you have to populate in these instances.

If you had 3 channels, you'd have to populate in 3's.

* General rules about RIMM:

1. The first element in a RIMM memory channel MUST be populated.
2. Any slots not populated by RIMMs MUST be populated with terminators/CRIMM's.
3. Elements on a section of the memory channel(s) must be the same size &amp; speed.
=> I.e.: All FIRST elemens on all RIMM channels must be identical.
=> ALL SECOND elements on all RIMM channels must be identical.

4. Can I mix sizes? In a limited way, yes.

Example - you have 2 memory channels (like on the 850 chipset) - this is what you CAN do.

A1 / B1 => First Element of channel
A2 / B2 => Second Element of channel

Read is as a table, going DOWN from A1 to B2 .

A1 -|- 64 MB -|- 128 MB -|-|- 128 MB
B1 -|- 64 MB -|- 128 MB -|-|- 128 MB

A2 -|- CRIMM -|- 64 MB -|-|- 128 MB
B2 -|- CRIMM -|- 64 MB -|-|- 128 MB

I hope that this explains it well enough for you .

AFAIK Intel's VC820 is the only board that has a single RDRAM channel. If such is really the case, then the VC820 *IS* the only board that can run with a single RIMM. It's - as said - all down to how many channels your motherboard has .