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

To: Joe NYC who wrote (40638)	4/24/2000 5:30:00 AM
From: Bilow	Respond to of 93625

Hi Jozef Halada; (LOL!) Re DDR taking more layers than RDRAM... In the Rambus fantasy land, people have a way of believing the darndest things. Here are the facts, with links so anyone can verify what I say at the source: (Note for mom and pop. These links are to engineering packages usually referred to as "gerber" files. If you want to read the artwork, you will have to get a gerber reader. The fact that you don't have access to one is probably an indication that you aren't in a position to be making big bets on the technology. But if you connect to these links, and expand the zip and exe files, you will find "readme.txt" files. Those files will show a lot of information about the PCB, including the number of layers.) First, lets grab the DIMM spec for the reference PC100 SDRAM. Intel has the standard DIMM design, taking a look at the gerber files gives a 6 layer board: 0.5 oz Cu ===== Signal 7 mils 0.5 oz Cu ====================== Vcc 10 mils 0.5 oz Cu ===== Signal 9 mils 0.5 oz Cu ===== Signal 10 mils 0.5 oz Cu ====================== Gnd 7 mils 0.5 oz Cu ===== Signal (exe) developer.intel.com Conveniently, Intel also has the gerber files for the standard RIMM module. Amazingly, it uses 8 layers!!! How could that be??? Rambus is supposed to make for cheaper boards!!! Clearly RIMM boards are going to cost more than SDR DIMM boards. PRI.ART ETCH LAYER 1 GND2.ART ETCH LAYER 2 INT3.ART ETCH LAYER 3 GND4.ART ETCH LAYER 4 GND5.ART ETCH LAYER 5 INT6.ART ETCH LAYER 6 GND7.ART ETCH LAYER 7 SEC.ART ETCH LAYER 8 (exe) developer.intel.com Now Intel didn't support the PC133 or DDR DIMM designs, so you have to go elsewhere for them. Micron has some data, as they pushed PC133 and now DDR. The files for the PC133 refer to the Intel standard, so reference PC133 cards also take six layers. The DDR DIMM reference is at micron and my oh my, it consists of only six layers. Whoa!!! That is just the same as the SDR DIMM!!! How could that happen??? Layer File Description L1 l1.art top etch L2 l2.art GND plane L3 l3.art internal etch L4 l4.art internal etch L5 l5.art VCC plane L6 l6.art bottom etch (zip) micron.com I think that the above links will provide a better reference than junk posted on Yahoo. I know that these issues are hard to understand for mom and pop, especially given the huge amount of hype that surrounds everything that the Bus does, but facts are facts, and DDR is cheaper. It's also at least as fast as RDRAM, and probably faster, so it provides better price/performance. -- Carl P.S. I should note that the above reference designs are not necessarily what DIMM and RIMM manufacturers are shipping. Engineers are always trying to save pennies on these things, and some of the layers in the above boards may be removed. But in any case, DDR is not any sort of disadvantage to RDRAM, and appears to be at an advantage.