Re: [LAU] OT: 32-bit vs 64-bit speeds

david wrote: Swings and roundabouts. On architectures like Sparc where the 32 and 64 bit CPUs have the same number of registers, the 64 bit OS is likely to be a little slower on operatrions like traversing linked lists because each pointer is twice as big on 64 bit and hence each retrieval of a pointer requires twice as much memory bandwidth as the 32 bit OS. When comparing 32 bit x86 to x86-64, things are less clear because the x86-64 has two more registers than the 32 bit version of the CPU which is considered rather register starved (in comparison to other CPUs like Sparc and PowerPC). The problem with register starvation is that the compiler has move data from registers to the stack to free up register space and this register spilling can slow down the program. The extra registers means that code written in the Ocaml programming language runs faster on x86-64 than on the 32 bit version of the program. Of cource all of the above assumes things like memory bus widths and bandwidths are the same. Newer CPUs are more likely to be 64 bit and have faster busses etc. HTH, Erik -- ----------------------------------------------------------------- Erik de Castro Lopo ----------------------------------------------------------------- "Arguing that Java is better than C++ is like arguing that grasshoppers taste better than tree bark." -- Thant Tessman