Confused... why so many?

I've had a lookat a mobo which already has 196Mb of rombus RAM installed (RDRAM), and the seller says that this figure can be upgraded as and when.
I've read about this RDRAM before, but know very little about it; is it any better / faster than DDR, and how much RDRAM can be installed in three slots?
Any pointers, please?
JB.

Welcome to the forums!

RDRAM is being superseded by ordinary DDR RAM, and with dual channel Canterwood/Springdale (Intel P4 boards) chipsets it pretty much owns any RDRAM. The technology is becoming outdated now, and the RAM prices are more than what you would get for equivalent DDR memory. Which is why it owns

Maximum amount of memory depends on your motherboard - it may only support 512 or 1GB sticks in a slot, so that puts an upper limit on the max amount you can put in. Some motherboards also can only run a few sticks of higher-speed RAM, as with the faster clock speed the chipset cannot drive multiple RAM chips fast enough. So if you want high speed RAM, you can only use 1 or 2 sticks - like with my A7V333 (AMD motherboard) you could only run PC2700 in the first 2 slots, and it had to be under 1GB of RAM or something.

If you want better performance and a wider variety of RAM, go with a dual channel DDR solution - the chipsets are called Canterwood or Springdale. Also, Pentium 4 chips such as the 2.4c and 2.6c overclock extremely well on these boards. If you can afford them.

Many thanks for that L337, from one Englishman to another!
So as I understand it, RDRAM was some sort of stepping-stone from SD to DDRAM during evolution?
Following that line of thought, perhaps it is for that reason that the price of RD is still so relatively high, as they didn't manufacture enough of it to recoup initial costs.
Thanks again,
JB.

Bingo - that's about right.

Well then, next question is pretty much predictable, isn't it?
Could I simply replace the RD sticks with DDR in the same slots, and would the machine work afterwards?
Heh!... I'm not too keen on fires in the house, nor smoking motherboards!
JB.

No, rambus and DDR platforms are incompatible physically and electrically.

At one time about a year ago, the price difference between RDRAM and DDR wasn't that great and RDRAM was faster, but like was said, with dual channel DDR RAM now being the hot ticket, people have abandoned RDRAM. Even though you can still get good bandwidth out of RDRAM, the high expense is not worth it. RDRAM is rapidly becoming obsolete. I'd also recommend avoiding it now, even though I was loving it a year ago.