The Truth About Processor Performance (a.k.a AMD GHz vs. Intel GHz)

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hey but i thought ddr2 was better than ddr cause the guy at the shop said ddr2 is duel channeling and will iprove my performance by double...
 
well the guy at the shop was lying. DDR has used dual channel for about 4 years now (i think). dual channel does not double performance but it does allow larger amounts of data to be transferred to memory at the same time because the memory bus is 128 bits wide rather than 64 bits. the only thing DDR2 beats DDR memory in is in frequency. the latencies are poor by comparison for example the best latencies i have seen for DDR2 are 3-3-3-10 for DDR2-400 versus something like my memory which has latencies of 2-2-2-5 at DDR-400 (incidentally can run at over DDR500 with those as well). in my opinion DDR is superior to DDR2 as a platform but unfortunately has frequency limits so AM2 can actually get higher bandwidths with top-end memory
 
mann that really does help.. ive always been a bit confused with those ghz and mhz... with amd and intel... how bout crusoe processors? or G5s
 
This has been a very much need post for a long time. I know that you have seen the wars between the AMD and Intel fanboys (I'm one of them) and despite the recent turnover by Intel, I am going to support AMD to the fullest! Thanks once again, great read.
 
Nice and lengthy, lots of good info, nice work.

But...

You compared a 2.4Ghz Conroe to a 2.6Ghz A64 X2? :p Amusing.

And just a minor correction, but Core 2 Duo has a 12-stage pipeline, not 14.
 
I have some questions.

As I know the Intel Northwood and Willamette has 20-stage pipeline , while the Prescott and Cedar Mill has 31-stage pipeline.

So, does this mean that Willamette and Northwood are faster than Prescott or Cedar Mill, if they are running at same freq



Also, I have another question. As I know Pentium 3 has 10-stage pipeline. So, does this mean that Pentium 3 is faster than Pentium 4 ?
 
@ Maroon1;

Pipeline length does not automatically translate directly to the performance. The complexity of the stages also plays a major role.

For example, consider the similar performances of a 2.0Ghz A64 and a 3.2Ghz Pentium 4. The A64 has a 14-stage pipeline, and the P4 a 31-stage pipeline, but the Athlon 64 is not necessarily any faster than the P4.

The Athlon 64 accomplishes this through the use of complex stages and a short pipeline. The Pentium 4 accomplishes the same thing through the use of a longer pipeline, and simpler stages. The effect is that the Athlon 64 can do the same amount of work at slower clockspeeds while the Pentium 4 has to push for higher clocks to compete.

It is true, that at the same clockspeeds, a processor with shorter pipelines and more complex stages will beat out a processor with longer pipes and simpler stages. So, to use your example, if you have a Pentium III at 1.0Ghz, and a Pentium 4 at 1.0Ghz, the Pentium III would indeed beat out the Pentium 4. However, the Pentium 4 was designed with longer pipes and simpler stages so that it could race ahead in clockspeed and beat out the older generation through the use of pure speed.

I'm not sure about how the Willamette and Northwood compare to the Prescott since there are many many other things even besides the simplicity or complexity of the stages that dictates the performance of a processor. But the premise behind the Prescott was to make the pipes even longer, and the stages even simpler, to achieve higher clocks than the older cores could provide. At this point, Intel still hadn't realized the brick wall of insulator leakage that would leave it's processors crippled before even hitting 4Ghz.

Hope that cleared things up a bit (or maybe just made it even more complicated, haha).
 
As I know the Intel Northwood and Willamette has 20-stage pipeline , while the Prescott and Cedar Mill has 31-stage pipeline.

it's not quite black & white. the "grey" area (i like this metaphor :D) is the scalability of performance. at the lower end of clock speeds when comparing say a Northwood and Prescott, perhaps at about 2.4GHz the Northwood would win out. the Northwood proved to not scale well with clock speed though and that is part of why they did not go much past 3.0GHz. while at about 2.8GHz a Northwood and a Prescott would be about even i think after around 3.5GHz Northwoods stopped providing significant improvements and the Prescott gained a sizeable performance lead.

yes the P3 is indeed faster than a P4 at the same clock speeds, it is well publicised. it wasn't until the Willamette hit about 1.7GHz that it could officially take the performance crown from the last P3s in all tests.

And just a minor correction, but Core 2 Duo has a 12-stage pipeline, not 14.

that is greatly appreciated :D. most of this information was originally typed at around 12:30am, without research :p.

NOTE: anything that doesn't directly pertain to understanding this thread/corrections etc will be split to another thread. spam of course will be deleted. i want this to stay clean and there is no need to post
well im a nubby here but i have a chance to build a computer the cpus witch a freind has but dont know witch one to take he said there both good . but need some help on witch one to take ? the both intels ones a pent D 805 and a pent 4 650 ht. which one should i take ? i love my games .
and the like. discuss away :D just don't hi-jack a moderator
 
That is a wonderful and most informational postÂ…great job!

Cliffs notes version of a wonderful post, which if you have the time read it, other wise here is a shorter less intelectual explanation to accompany the original post. Latency is the keyword here...AMD architecture has been lower in latency for a long time...this is why they have performed better. Think of it in terms of a two straws trying to draw on the same liquid...one is a .0625 in diameter and the other is a .25 in diameter. In order to get both strawsÂ’s to draw the same amount of liquid the .0625 will have to work harder than the .25. Same principal in the CPU architecture. Lower latency means better performance. I just hope AMD can make a come back with the QUAD cores coming out soonÂ…I really hate intel.

-HBBK131 :D
 
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