Memory question

[Pixelsponge]

Out of curiosity, what the hell is the deal with RDRAM? Why is it so much more expensive? Do I have any advantage at all using it? Lowest price for a stick of 256 is $104 on pricewatch, and I have to buy the stuff in pairs. Anyone know where I can get it cheaper?

[[AK]Squidly]

I believe the price is for 1 pair. In other words, I bought 256 meg of RDRAM and got 2 sticks for the price.

[Hale]

Thats Rambus ram isn't it? Its not compatible with the other memory technologies out there. What memory does your botherboard take? PC133, etc?

[[AK]Squidly]

Yep, Rambus. Looks different, tastes different. Costs different :P

[Pixelsponge]

So you got two sticks of 128 then? Where did you buy yours?

[[AK]Squidly]

Staples. It was the only store in my area that carried what I needed.

[[AK]Gunny Highway]

The prices on pricewatch are per stick. If the quoted price is for 256mb then you get one 256mb rambus module. unless otherwise specified in the description.

[Pancito]

Do you have to use them in pairs? i think (i dont remember well) i once used rambus on a PIII system, and i only used one stick. so i don't know about the pairs issue, if so ahh it reminds me of the old EDO Days. Back in the day i bought 2 megs of ram for $200 so 256 for $100 is dirt cheap rambus is faster, there are 2 kinds the 800Mhz and the new 1066(???) Mhz as you can see compared to 133Mhz from the old technology is a lot more bandwidth. For i was told Windows XP was design for RAMBUS memory.

Is like buying in advance, you insure yourself that the memory bus wont be the problem of future bottlenecks.

[[AK]Gunny Highway]

Yeah I have a rambus system running xp pro. With rambus memory you do have to use them in pairs but I am happy with the results. Not to mention if you go to www.pricewatch.com you can get the best price.

[Zorro]

Originally posted by pancito
For i was told Windows XP was design for RAMBUS memory.

That's like saying parachutes were designed for the Space Shuttle... RAMBUS memory works in a system that is designed for RAMBUS. Since no operating system talks directly to a system's memory, Windows XP could give a flip what kind of RAM you have plugged into your motherboard (and, to a lesser extent, it's not too worried about the motherboard, either). The problem with the general populace is that they only see the big number in front of the MHz and don't bother to realize that RAMBUS is only a 4 bit data bus, in contrast to the 32 bit data bus that comes with SDRAM. Hence, RDRAM has to be 8x as fast to keep up with SDRAM's parallelized architecture. For those of you that own Intel setups with RDRAM, I don't mean to diss your rig. I just have issues with the company RAMBUS and would rather spend my money elsewhere when possible... I just can't do business with a company that joins an open-standards consortium of businesses and then quits the consortium only to patent the ideas that came from said consortium... Thank you, RAMBUS...

[Hale]

4 bits? Blech. Seems an odd thing to do.

[[AK]Gunny Highway]

Zorro not to knock you off your soapbox but 4 bits is inaccurate. read the following:
Rambus uses a 16-bit bus

Both currently available versions of Rambus and DDR have basic clock rate per bit transfer limitations (i.e. 800 Mb/s per data pin RDRAM, 333 Mb/s per pin DDR). There is an architectural limitation for DDR which was addressed by Rambus by using controlled impedance and a serial connection for modules, whereas DDR is an extension of SDRAM where you have a parallel bus structure with modules acting as un-terminated 'open stubs' on the bus (potentially resulting in signal integrity problems at high speed, such as signal reflections).

A serial bus, by electrical limitations or laws of physics, can sustain a higher bit rate per data pin than a parallel bus. Why is this? Because it has controlled impedance, no open stubs, and proper transmission line termination on the bus. This is part of the reason that you have to use continuity RIMM in empty RIMM slots to ensure reliable performance.

In order to overcome some of the limitations, DDR circumvented this data transfer rate restriction this data transfer rate limitation through the use of a wide, 64-bit bus, whereas Rambus only uses a 16-bit bus. Of course this has led to some additional problems with signal integrity issues when multiple sticks of DDR are used on certain motherboards. More module sticks on the parallel bus result in more signal integrity issues that need to be resolved. We have even seen this in the debate over the nForce Superstabilty mode. Although not as well known the Tyan Trinity 510 also suffers from some of these issues as well and is forced to throttle down the speed of it's DDR as well when multiple modules are used.

The reason for this, above all, is that at higher clock speeds,RDRAM is the only type of memory that can make use of the increased bandwidth of the fastest CPUs. Still, RDRAM has had to fight against a big problem from the start in order to make it in the mass market: the price for the module is higher than that of SDRAM. Much has been made of the price vs. performance ratio of RDRAM, but the truth is that RDRAM is expensive to produce and cannot be produced or tested on the current equipment that most DRAM companies currently have. Of course if these memory makers are going to have to invest millions of dollars in order to upgrade their equipment, some of this cost is going to be passed on to the consumer, which in part leads to the current higher cost of RDRAM.


Zorro you still own the skies and please don't accidentally drop a bomb on my head

[Hale]

16 bits makes more sense, which is why you need to 2 to marry up to a 32 bit processor.

Back in the good old days, we had 8bit memory and 32bit processors and needed to install four banks at a time.