Hardware news: XDR - DRAM, Memory Controller, and IO Cell
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DRAM is the RAM itself. This isn’t very different from the current generation of memory. There will be manufacturers making them, such as Samsung and Winbond. They will be available in different memory capacities and speeds.
The memory controller will work the same way as the current generation of memory controller works. The memory controller is basically what directs the traffic of the front side bus to and from the memory. The game plan is to have all XDR devices use the same IO Cell and Memory controller. They may have to be modified, but you could theoretically upgrade the RAM in your Playstation 3 -- oops, did I say PS 3? The biggest miss of the RDRAM was a single channel only. DDR was able to run in dual channel and quickly took over the market. XDR RAM may possess the ability for dual channel.
Clocking
Now it's time for the good stuff. Most people don’t care about memory controllers and IO Cells, just how much they have and how fast it is going. The new memory will use mesochronous interface, meaning it will transfer on a fixed, but arbitrary phase. The most important thing to take out of the clocking is that it will be multiplied. If I said “4”, “PLL”, and “Multiplier”, I would hope Pentium 4 would ring a bell inside your head. Intel calls this Quad-Pumped. Have you ever looked at what the FSB is really running at in your BIOS, and seen 200, not 800 as Intel advertised? The 200 FSB is quadpumped; Intel, being the marketer they are, calls this an 800 MHz FSB. XDR will work in the same way as Intel’s quad pumped FSB.
Octal Data Rate
The whole idea of memory is to provide the CPU and other components with data faster than the hard drive. Many people confuse bandwidth with speed when talking about memory. Yes, fast memory means more bandwidth, but there are other factors that make a bigger difference. XDR features Octal Data Rate; this means it will be able to transfer eight bits of data per clock cycle. DDR offers two bits per cycle and DDR2 offers four. If the XDR is running at 400 MHz, it will be able to deliver 3.2 GHz data rates. With each generation of memory we double the bandwidth without increasing the speed at all.
Next: Bandwidth >>
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