1. "...is the gain that the nForce gets because it's ratio is closer to 1:1?"
No. nForce is still limited by the FSB at 100MHz or 133MHz. So it will only yield a fractional gain with any memory system with a signal faster than the 133MHz FSB. The system clock is driving all of it. AGP, CPU, PCI, etc. are all multiples of 100 or 133.
2. "Also how does having DDR400 over DDR266 help if FSB is still 133?"
DDR400 is on a 200MHz clock. So just like RDRAM, it has to be translated for the FSB. It is like the transmission on a car. The controller puts both FSB and the Memory bus in harmony with each other. So if the speed to and from the memory is faster to the FSB then the overall process will improve, however only fractionally.
It is like two guys that are working together in an assembly line. Man #1 is waiting for parts from #2 to finish what man #1 is working on. Man #1 is the FSB/CPU and #2 is the memory/memory bus. If #2 always has parts ready for #1 then #1 will do his job in an efficient manner. If however #2 can have them ready for him and organized and ready for #1 to use then the process can improve slightly. The whole operation is still dependent on #1.
3. "Doesn't what you said mean that having 133FSB limits your memory bandwidth to 2.1GB/s and having anything over that is not only useless but it negatively effect system performance as it wouldn't be 1:1?!"
First, the memory bandwidth is for the memory bus itself. So the FSB does not limit the memory bus. They are two different buses.
Secondly, it will not negatively effect the process. Only fractionally improve it. This why there have been greater yields with DDR333, DDR400, and dual channel DDR systems. Those greater yields are only minimal at best. This is what I mean by fractional.
As the ration between FSB and the memory bus reach 1:1, the better the system will operate. For a long time the FSB was 1:1. PC66 and 66MHz FSB, PC100 and a 100MHz FSB, PC133, and even DDR266 with an effective 266 MHz FSB. Until the ratio goes back to 1:1 there will only be fractional gains. Intel engineered systems with 1:1 ratios. (An effective 533MHz, 133MHz x 4 channels, with PC1066 which uses a 533MHz clock.) Hummmmm.... Dual channels, a DDR signal, and at 533MHz equals the bandwidth and clock speed of the FSB.
This could be one reason that the AMD will have the memory controller in the integrated northbridge on the Hammer's die. Only time will tell on that CPU for sure.
<b>"If I melt dry ice in a bathtub, can I take a bath without getting wet?" - Steven Wright</b>