PC2700 labeled as "Not Dual-Channel Compatible" (huh?)

What does that mean?

I believe that means that they want you to buy the retail package of 2 modules in order to not have people buy two pieces of KVR with the same specs, but different ICs and not have them work together. It reduces their RMA exposure because should you buy it and it not work together, they can tell you that they specifically "told you so".

In reality it means nothing, if you get the same ICs then for all intents and purposes it is no different than the 2x kits. After all, its not like they actually test the kits for compatibility, they just box up two modules with the same ICs and call them a Dual-Channel Kit.

By the way, just like the sticks you have pictured, I've seen this only on the PC2700 boxes from Kingston, not the PC3200.

Nothing but rubbish. Memory is memory is memory. Dual channel works so long as the DIMMs are similar enough, i.e. same number of chips & same capacity.

How can you tell though, I mean, I've had three same sticks in and CPU-Z still reported the setup as dual channel?

Usually it's the same size RAM in slots 1 & 3, right? But how can you tell without opening the case?


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[210] FSB x 11.5 = 2415 MHz @ 1.85 Vcore with memory frequency at 100% [210 FSB] @ 2.90 Vdimm and 1.8 Vdd
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Kingston is notorious about using different chips in their modules depending on supply. All they are saying is you are not guaranteed this stick will play nice with other sticks. They would prefer to sell you a dual channel kit of two sticks that are perfectly matched. That's not to say your single module in the pic won't work in dual channel with other RAM, but perfectly matched sticks will O/C better together. At default speeds, I doubt you'll ever notice.

Yes, I understand the gains are often minimal.

But the question stands... how can you tell without opening the case?

One 512 stick and two 256 sticks were said to be able to make up dual channel setup, I was always confused about that...

The nForce2 chipset will allow you to use 256 and 512 sticks together and operate in DC mode if configured correctly. There first thing to keep in mind is that the max memory that will work in DC mode is 2x the amount of ram in the channel with the single slot. Most mobos have this closest to the cpu, however some boards, like the Abit NF7 for example, have the single slot furtherst from the cpu.

If you use a single 512MB stick in the single slot, then you can run a single 512 or 2x256 in the channel with the two slots and ALL of your ram will be accessable by both memory controllers concurrently and you will have a full gig (2x ram in first slot or 2x512) in DC. The chipset is limited to 2GB in DC, therefore, you could use a single 1GB stick in the single slot channel and 2x512 in the two-slot channel and have two gigs in DC.

You can also be setup in such a way that you wil have some of the ram accessable by both memory controllers and some only by a single controller. In that situation, CPU-Z will still report that you are in DC, because in effect you are, but just not for all your ram. An example would be when using 3x512 sticks. Going back to the basic rule that the max in DC is 2x the single slot, you would have a gig (one 512MB stick from each channel) accessable by both memory controllers concurrently (DC) and one 512MB stick in the second channel operating in single channel mode and only accessable by the memory controller for that channel. It is a little weird, but I've read several articles that addressed this when the nForce2 first came out so I am pretty comfortable with what I've posted.

If anyone wants links, let me know. It might take a few minutes to find them, but I will be able to, I'm sure.

So what about PC3200 RAM labeled "not compatible" with DDR 333 PC2700 CPUs...

Probably meant as a CYA on all of the OEM systems that don't provide for manual settings of ram speed and timings would be my guess.

The bottom line is that disclaimer is probably there to cover their arses. No other real reason.