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Technology Stocks : Rambus (RMBS) - Eagle or Penguin -- Ignore unavailable to you. Want to Upgrade?

To: Scumbria who wrote (39970)	4/15/2000 1:55:00 PM
From: Zeev Hed	Read Replies (2) \| Respond to of 93625

Scumbria, you get "faster" transistors in two ways, you reduce features (good for cost) and you increase threshold voltages (bad for heat dissipation) (and that a very "simplistic" description). I am not sure about DDR for the simple reason that not enough of these (and their associated chip sets) are out there. One thing, I would postulate, is that as speed increases, engineers will have to learn to perfection the religion of transmission lines, since at the 500 MHZ and above range, every parasitic capacitance, mismatched terminations, open lines etc will be a source of headaches (as we have learned from the third open connectors in the early 820 fiasco). I am sure that similar problems are going to crop up for DDR. Sure, DDR is a more evolutionary development (of SDRAM) when compared to RDRAM, but that is also its Achiles heel, it frequency extensions capabilities are limited just for that reason. Zeev

To: Scumbria who wrote (39970)	4/15/2000 3:37:00 PM
From: Barry Grossman	Read Replies (3) \| Respond to of 93625

Scumbria, , I don't see how DRDRAM ever gets critical mass to catch up Do you believe that Willamette which WILL ONLY USE RDRAM will not be Intel's mainstream desktop offering next year? Its introduction in the 2nd half of this year will surely demand increased RDRAM production as it ramps and replaces Coppermine on the desktop. Might we call that critical mass? Or, do you think Intel will sell miniscule numbers of those chips? Do you think they are spending $6B this year to increase production of something they won't sell? Give me a break! Oh yeah, do you also think that the PS2 will fall on it's face this Christmas? Barry

To: Scumbria who wrote (39970)	4/15/2000 5:48:00 PM
From: Bilow	Read Replies (3) \| Respond to of 93625

Hi Scumbria; About those DRDRAM transistors... I don't think that RDRAM requires faster transistors, that would be quite a difficult feat. In fact, RDRAM used 2.5V while the rest of the world was at 3.3V. Since propagation delays in CMOS scales inversely proportional to voltage (with all other variables, particularly process held constant), that would suggest that RDRAM's transistors were 33% slower than other standard DRAM at the time. This is basically a fact that doesn't matter much, as far as the bus interface goes, I would guess that the average FET has a low enough on resistance to make the design work. Where they would run into problems is in the spread of the process. RDRAM has got to require a relatively tight process. As far as sources goes, I have seen this mentioned in the trade press repeatedly, but you aren't going to see Samsung issue an official press release saying that their process isn't good enough to reliably produce RDRAM with a high yield. (If you did see it, it would be in the justification of an official decision to drop manufacturing the part.) What the memory makers were leaking was that if they converted to RDRAM, their standard process would have a good yield, but as soon as their process got a little off, they had to throw away a batch. Regular memories aren't as sensitive to process, so they can sell them a lot cheaper. This is all in addition to the die penalty, which in itself is a non-linear cost increaser. It basically boils down to the same thing that faced the motherboard and RIMM makers. They had to tighten their tolerances in order to get the repeatability required to control impedances to the specifications required. Same thing happened to the Camino chipset, no doubt. Tight tolerances reduce manufacturability. On the few occasions I have had to make PCBs (for my own projects), I've always been careful to use spaces and traces 50% larger than the PCB house claimed their process could achieve. That way I ended up with boards that didn't need testing. (And so are cheaper.) Rambus really didn't provide an advance on PC memory technology. Everybody already knew that if all the components were perfect you get more bandwidth per pin. It's all a matter of tradeoffs, there are no simple solutions, or one-line answers to engineering. Requiring tight tolerances raises the cost of production. Reducing pin counts reduces the cost of production. Which is more important? Anybody who tells you that one or the other dominates in all situations just doesn't know what he is talking about. The world just isn't that simple. -- Carl