Joe, <In that case, if the latency is only a grain of truth and a pound of bull, why does Intel and AMD create more and more elaborate caching schemes?>
You missed the point again. Latency IS key. There's no argument. However, high bandwidth conditions can increase the average latency that the CPU sees. What the anti-Rambus coalition is talking about is low-bandwidth latency. See below.
<If the peak bandwidth is not the performance bottleneck, why throw your limited dollars fighting something that is not a problem?>
Rambus was chosen by Intel years ago. A lot can happen in a few years, and Intel was trying to forecast bandwidth requirements several years out. I'll bet a lot of the decision-making was based on the transition from EDO to SDRAM. Same thing with the transition from 66 MHz to 100 MHz FSB. When the transition was made, there wasn't much noticeable difference in performance. But now things are different, and now these technologies not only make a real difference, they're pretty much taken for granted.
What we see now is perhaps Rambus being somewhat ahead of its time. The bandwidth requirements of today's applications probably aren't as high as Intel previously thought. The sole exception is workstation apps, which can use all the bandwidth they can get.
<Suppose you decide to spend $400 on Rambus memory. Now you have $300 less to spend on other components. You will end up with slower CPU, slower and smaller hard disk, less memory. Essentially, using RDRAM in a computer cripples the performance.>
By your logic, no one should be buying 1 GHz processors either. All you're doing is throwing away hundreds of dollars for an extra 50 or 66 MHz. You'll end up with less memory, slower graphics card, slower and smaller hard disk, etc. Essentially, having a 1 GHz processor in a computer cripples the performance.
By the way, where did you get the $300 figure? Ask any pro-Rambus person on this thread, and he or she would be glad to show you two comparable Dell systems, one with RDRAM, one with SDRAM, with a much smaller difference in price than $300.
Tenchusatsu |
