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Intel Encounters Another Problem with RAMBUS
Palin Majere writes, "News.com is reporting that Intel is once again having problems with its RAMBUS memory chipsets. This time, it's affecting the i820 and i840 chipsets, and is located in the chipsets (MRH and MTH) that allow customers to use regular SDRAM memory instead of RAMBUS memory.
It causes memory corruption and has already caused Intel to cancel three motherboard designs as a result. " With the continuing shortage of high-end Pentium processors, and stuff like this, it's no wonder that AMD has been doing better and better.
It's failed.
I hope Intel, and other chip manufacturers learn from this. Secrecy and control aren't cool. They can, and will, turn around and bite you.
IMHO, Intel's best hope of survival, never mind market domination, is to open the RAMBUS specs completely. Do a hardware variation of the GPL. If they don't, it's going to bleed them dry. If they do, sure, there'll be clones, but Intel will still exist.
Given the choice of pride or survival, Intel needs to think about that survival option a bit more.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
The MRH's are Memory Repeater Hubs, and come in two flavors - MRH-S and MRH-R. The -S does translation from rambus to normal SDRAM. The -R is to let you get aronud the 2GB limit on rambus. A rambus channel can have up to 32 256Mb devices, or 1GB. An MRH-R has two channels dangling off it, doubling capacity. Put two MRH-R's on one channel from the chipset, and you can have 4GB.
One interesting thing about this solution is that it takes time to go through the chips, increasing the already high latency of rambus.
I wonder if Intel would alter their decision on Rambus, were they able to go back in time and do so. They might pull it off yet, but it won't be easy. If it does work, it will only be because they are Intel.
The enemies of Democracy are
Reading the article my take on it is that the problem is in the device that does the SDRAM to RamBus conversion (ie it's a channel adaptor that lets them mix and match rams types) - and the problem only occurs when you use ECC.
I can think of 2 reasons this might happen - either they got the ECC logic wrong (probably likely), or there's a noise problem on the sdram side when they drive 72 data pins [for ecc] rather than the usual 64 (less likely). Either way it isn't a RamBus problem.
There's a lot of noise made about the various merits of memory types - my personal take on it is that it's mostly a wash, RamBus drams do have some advantages - but for main memory systems they are more in the future (and revolve around how many chips it takes to make a minimum memory sized system as memory continues to move down the memory density curve - M$ may of course make this moot). Their main disadvantage is cost - and it's rather a chicken and egg sort of thing - if people use them a lot the marginal cost of RDRAMS will probably go close to 0 - but if people don;t use them in volume because they cost more that won't happen. Remember in the core of a RDRAM is the same core that's in an SDRAM it's just the interface circuitry to the pads that's different.
Rambus is a design for a memory system from Rambus Inc. It is extraordinarily fast on paper. Intel chose their design and decided to support it on a lot of their new products.
The implementation took a long time to get around to getting around. It is now here. Intel bet a LOT on Rambus, because it would give them significant control over a lot of markets. (IE: They own rambus designs)
Rambus is significantly different from the DRAM used commonly today. It requires changes to how stuff is laid out on the motherboard. And it is manufactured differently, to very demanding tolerances.
It is now in production and is competing with DDR-DRAM, which uses existing manufacturing processes, generally works with existing chipsets, and is easy to support. And it doesn't require a fan setup for the memory alone. And runs far cooler. And gives almost as good performance when set up correctly as a RAMBUS setup. And is also capable of being manufactured in quantity, whereas RDRAM is extremely difficult to manufacture. DDRDRAM is also about a fifth of the cost of a RDRAM setup.
You do the math, and read up on it a bit.. I think you will agree that for all intents and purposes (read: mainstream pcs, servers, et al), Rambus is DOA.
Toodles.
-troll taker