WarmFluffyUK
The Big Wad Bolf.
abigsmurf posted on Aug 16 2005 at 03:01 PM said:Jarska333 posted on Aug 16 2005 at 11:06 AM said:DaveC posted on Aug 16 2005 at 06:07 AM said:A pentium is a CISC where as the ARM is a RISC. A pentium is more powerful than an ARM MHz for MHZ. So a 200 MHZ pentium may be like a 400 MHz ARM.
Hum, I was under the impression that RISC was more powerfull. Reduced instructions or something, opposed to complex instructions...
RISC is meant to allow for more instructions per cycle than for CISC but they're much simpler instructions. If you don't use fixed point maths, the speed goes way way down.
RISC = Reduced Instruction Set Computer
CISC = Comples Instruction Set Computer
Think of a CISC as your standard CPU, with a full instruction set. Then one day some bright spark thought that computers on average use about 20% of the instruction set. So He designed a processor with less instructions. The idea behind it was this: some of the CPU time is wasted as it trawls thru a list of instructions, if it has less instructions then it should in theory cycle faster. The downside is though, that the guy writing programs to run on it (the coder) has to write larger and slower code to make up for all the functions (instructions) that the CPU doesn't have. So it's always a bit of an argument between smaller code and slower CPU or larger code and faster CPU.
These days with the newer CPU's though, the line between CISC and RISC is getting less. There's not a huge difference anymore. But they are still labeled CISC or RISC due to their legacy.
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