RISC vs. CISC?

[Joseph F]

Could someone explain to me the general Pros and Cons of RISC and CISC processor designs?

 

[Mars999]

http://arstechnica.com/cpu/4q99/risc-cisc/rvc-1.html

 

[Joseph F]

Ah, so now the line between "RISC" and "CISC" is so blurred that there are no "pure" CPU architectures from either camp?

Thanks for the article, it explains a lot.

 

[Edrick]

Yea, this was a good discussion 10 years ago. Now RISC is relegated to niche markets unlike the 1990's where a RISC workstations were competing with Intel.

 

[Snooper]

Holy Last Century, Batman!!!

The whole RISC vs CISC debate was interesting at the time with a lot of diehards on both side claiming only THEIR side could POSSIBLY win. The real funny part of this is how the RISC systems slowly added more CISC like features to improve performance and the CISC systems slowly added more RISC features (also to improve performance) until there wasn't a nickel's worth of difference between them and the whole debate sort of just faded away.

 

[Edrick]

The real funny part of this is how the RISC systems slowly added more CISC like features to improve performance and the CISC systems slowly added more RISC features (also to improve performance) until there wasn't a nickel's worth of difference between them and the whole debate sort of just faded away.

Well, Some companies still offer both lines (or at least they market them that way). Intel has Itanium (more RISC) and x86 (more CISC). IBM has Power7 (more RISC) and z196 (more CISC). Both are targeted at different market segments of course.

 

[JFAMD]

Here is the debate: does my software run on RISC or CISC?

The simple answer is everything in life is driven by software. Focus on what you need to do the job.

RISC and CISC both have their strengths and weaknesses. Use a hammer to put a nail in a board. You can use a screwdriver to hammer a nail into wood (yes, I have done it), but it isn't the way you'd want to approach that task.

 

[wahdangun]

Here is the debate: does my software run on RISC or CISC?

The simple answer is everything in life is driven by software. Focus on what you need to do the job.

RISC and CISC both have their strengths and weaknesses. Use a hammer to put a nail in a board. You can use a screwdriver to hammer a nail into wood (yes, I have done it), but it isn't the way you'd want to approach that task.

yes thats true, but isn't amd k6 use RSIC in its core?

 

[Joseph F]

From what I've read virtually all x86 processors have "RISC" cores. AFAIK all of AMD's CPUs since the K5 have had RISC cores. And all of Intel's CPUs since P6 have had them. (Not sure if Atom has it.)

 

[Cogman]

Today, the only real difference between CISC and RISC is variable length instructions. Past that, they are pretty much the same.

 

[jhu]

Well, Some companies still offer both lines (or at least they market them that way). Intel has Itanium (more RISC) and x86 (more CISC). IBM has Power7 (more RISC) and z196 (more CISC). Both are targeted at different market segments of course.

I wouldn't call Itanium "more RISC". It's kind of out there in its own space (EPIC). Nowadays, the only CISC-like thing that x86 has is the variable-length instruction set. Past that, it's load-store with simple instructions.