ashfame said:
wht are memory controllers?
how it varies the performance if they are inbuilt or outside the processor?
Mermory controllers read/write, to/from the memory. So if this controller lies inside the CPU. this mean CPU directly accesses to RAM. This has the following effects:-
1) Faster access, since request do not need to go via FSB (like in the case of Intel) better for games.
2) A64 CPU are not that much cache dependent for example 512KB to 1MB cache only produces 5-10% of performance improvement. This is because small bits of data r read very efficiently from RAM. On the other hand Intel CPU are heavily dependent on its size, A64 CPU perform better even with half as much cache as on Intel. Since cache takes almost 70% of the silicon die size of the processor, thus AMD CPU are cheaper to produce.
3) No need for a north bridge (contains memory controller), so motherboards are cheaper to produce
4) It has limitations, A64 CPU cannot drive more than 2 RAM sticks at full DDR400 speed per channel. This means at full speed use can use only 2 RAM sticks for Socket 754 and 4 RAM sticks in socket 939. Intels dont have this limitation.