Higher than what…PC100? OK, certainly, but not even equal to DDR at 133Mhz.
The addition of the high-speed interface results in a small increase in die size, but also allows higher performance to be obtained.
They mean like DDR.
In contrast to current SDRAMs, memory systems that use RDRAMs transmit addresses and data in a wave-pipelined manner on both edges of the clock.
In reality, the higher bus speeds along with the protocol nature of RAMBUS cause the motherboard design to be MORE limited often requiring additional layers to be added to the board to allow a lower signal to noise ratio. While I personally like to see all my bus lines straight from point A to point B, it is nice to be able to move one around a bit to fit things in if needs be. This luxury is not an option with RAMBUS. It is very sensitive to impedance differences from one line to the next. The net result is that the system is more expensive.
The high per-pin and per-device bandwidths of RDRAMs have several system-level advantages. Providing high bandwidth from a small number of pins means fewer bus traces to route. In addition, the fact that the Rambus channel is routed in parallel means simpler routing and reduced complexity of motherboard designs. Often, simplified routing can result in fewer motherboard layers, reducing manufacturing costs as well.
LoL. I love this stuff. On the DELL web site it shows a $480.00 128mb upgrade. This is to compete with 128mb of PC133 at $89.00 on price watch (granted, this is cheep memory, but so is the memory in the DELL. I have heard it is only PC700 at best...at worst PC600. By my math that is a 539% increase in price……hardly a bargain in my book.
The high price is often attributed to factors including low yields, large die sizes, the cost of new equipment, and royalties charged by Rambus. However, several of these explanations have recently been called into question. An interesting point is that the price premium for RIMMs in the retail channel is higher than the premium for RIMMs purchased from the major OEMs. The Dell website, for example, allows prospective buyers to configure systems with varying amounts of RDRAM. The cost of upgrading a system to include an additional 128 MB RIMM module is much lower than for purchases made through retail channels, and has even been dropping recently. This calls into question the exact cause(s) of RDRAM price premiums. Central to this controversy is the difference between price (what a consumer pays for RIMMs) and cost (what it costs a manufacturer to produce RIMMs).
Although the first sentence is true, RAMBUS has inherent yield issues. The higher clock frequency needed (currently 4X the clock as SDRAM) makes the design much more expensive…..but everyone knows this. A 4x faster processor will certainly cost more and have lower yields than the slower one. It will additionally have more sensitive traces, more expensive mb design, higher heat dissipation, and larger power requirements.
Any new technology has lower yields than the incumbent technology, and has development costs that must be recovered, so one would expect some premium to be paid initially for RDRAMs. But this article suggests that the cost of manufacturing RDRAMs is not the reason for the RDRAM price premiums in the retail market.
Yea, yea, sure, sure. You can test each chip prior to assembly; however, you still have to validate the entire package once assembled. RAMBUS is so sensitive to timing, that manufacturing differences in one PCB to the next can affect the max speed rating of a RIMM. Besides, this is an invalid arguement since the entire assembly must be tested anyway right?
As an aside, it has been rumored that RDRAMs are first tested when they are placed on RIMMs, and that low device yields mean that the entire RIMM must be thrown away if one bad device is found. This is not the case. RDRAMs are tested in much the same manner as SDRAMs, with functionality being verified before devices are assembled onto RIMMs. The high operating speed of RDRAMs, which exceeds the operating speeds of previous DRAMs, means that new high-speed testers are needed to test some functionality. While there is an investment for this new capital equipment (which must be recovered), it has the advantage of being able to test RDRAMs at full speed, meaning that test time per RDRAM is reduced and test throughput is increased. Agilent describes this advantage in a recent press release.
I have heard 5%. We must be talking to different analyst. As I understand it, the royality percent is on a sliding scale. You get a better rate if you sell more. Intel is on the hook for quite a few of these jewels. With their projected volumes, 2% may be an accurate number, but even so, this is still more than the 0% of SDRAM or DDR.
Analysts estimate the royalty Rambus receives to be about 2% for each RDRAM sold. This is very small compared to price premiums seen in the retail channels today, and is thus not a major contributor to these premiums.
Dean Kent at realworldtech (the links from the above posts) has always been a pretty non-biased source of technical information. I don't consider his analysis to be discounted easily.
RAMBUS IMHO is simply not a viable solution when compared to DDR. It is not really a good solution compared to PC133. Give the incredible amount of technical information against RAMBUS memory, it is understandable how some have questioned your motivation. I agree with UncaMilty on this one (nice post by the way)
Any defense or replies to my arguments would certainly be welcomed.
I think that your article is, at best, incomplete. At worst, it is a slanted attempt to promote a technology that is being almost universally panned with good reason.
[This message has been edited by OneEng (edited 05-10-2000).]