Amd Pipelines

[Kamikaze_Badger]

Please note that I'm not an expert on CPU architecture, or pipelines for that matter.

 

But... if shorter pipelines mean better multi-tasking and gaming performance, and longer ones mean better A/V encoding and file encryption, why doesn't AMD release cores with significantly longer pipes, and cores with even shorter pipes, add a few bucks onto the price, and then start selling those as CPUs for specific purposes?

[danyo64]

i'm guessing b/c they would have to redevelop the entire cpu architecture, and they can only develop so many processors at one time. they dont have infinite employees, funds, time.

[Kash]

I don't think it's as simple as just making the pipelines longer or shorter. It's a system dependant upon various parts that make up the entire architecture. Plus, the pipes aren't just shorter, they're are also WIDER than the ones in the Netburst architecture that P4 processors use.

 

Plus, we already know that in general use, the AMD architecture beats the P4 architecture hands down. Even in applications that show performance benefits with a P4, those benefits are generally nothing spectacular. Sure, a few minutes is a big thing for most professionals, but then again, image professionals aren't exactly buying the average thousand dollar PC.

 

Even if the average enthusiast is building a PC for mainly AV use, AMD processors can still hold their own against P4 equivalents, and generally do it at a lower price to boot.

[Sovek]

much lower price and much cooler,

 

I have sworn off Intel chips for good, no way am I getting another Intel chip

[martymcfly]

There are reasons the pipelines are the size they are and many other features are the way they are, which is to make room for other things and general physical limitations. For example, when intel added 512kb of cache to their p4es to create the prescott core, this involved makeing the pipeline longer (cancelling out the performance benefit) and altering other things, greatly increaing the temperature.

[BabyBalrog]

Longer pipelines temd to alow the CPU to run faster, but also hotter because it takes more transisters to make a logner pipe. The long pipe is good for doign things that are non branching, but more repetative.

 

The Short pipe works best for Branching, and therefor AI like Games, multitasking, and suffer less from a cache miss, meaning cache size is less important, (also aided by the AMD64's onbaord memory controller.

 

in the end a pipeline stage is jsut a breakup of the entire instruction so a 12 stage pipe brreaks an instruction intoe 12 stages and executes it so it needs 12 cycles to finish teh entire intrsuction and presscott s 31 stage pipe needs 31 steps so the shorter pipe is much more efficient untill the 31 pipe is runnign 3 times faster then the short one, which is what Intel wanted to do with the Prescot. So the Northwood 20 stage pip at 3.2 Ghz was about as efficient as the AMD 12 stage pipe at 2 Ghz.

 

20/3.2 = 6.25

12/2 = 6

 

and if you notice the 2Ghz AMD64 was the 3000+ connection?

[Guest Raven65]

Well we also have to lookat patents, AMD might not be able to make the chips with longer pipes. Unless they come up with a totally different archiecture. That takes time and a lot of research money.

[ady1989]

^^ yep