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Re: Differences between AMD and Intel CPUs [was: Re: Dragonfly andHyperthreading....]

From: EM1897@xxxxxxx
Date: Fri, 11 Mar 2005 13:09:52 -0500

In a message dated 3/11/2005 1:05:07 PM Eastern Standard Time, "Thomas Edward Spanjaard" <t.e.spanjaard@xxxxxxxxxxxxxxxxxx> writes:

><EM1897@xxxxxxx> wrote in message news:6C3B2051.2AA8F267.000424FF@xxxxxxxxxx
>> Well sorry, but you are just completely wrong about
>> everything. I've already cited the P8SCi as an example,
>> Im sure you know how to use google to get prices.
>I was talking about both a CPU and the motherboard which you were claiming. 
>In your P8SCi example, you left the CPU out of the price.

I said $360. for both, if you care to actually read things.

>> Your "test" is also completely wrong, and your analysis
>> of the bus wrong as well. For example, passing 80Mb/s
>> through a box with a 33Mhz/32bit nic might use 50% of
>> the cpu, and you pop a pci-x card of the same type (say
>> the em driver) and it will drop to 1/3rd of the usage.
>> Saying that you can pass some amount of data is not a
>> useful analysis, because if you use 100% of the cpu
>> instead of 30% to achieve the throughput its worthy
>> of note. There are 1000s of I/O operations that are not happening in the 
>> background, and as the bus saturation increases,contention increases and 
>> those operations take longerand longer. Its not rocket science, its very 
>> easy to
>> look at the interrupt load with different kinds of
>> cards. Anyone that thinks the way you do just isn't
>> paying attention. But, its very typical of what I've
>> been saying. That is, that a lot of people who should
>> know better don't seem to understand the basics of
>> what the real bottlenecks are. It seems almost comical
>> that teams of engineers are rewriting an OS trying to
>> squeeze some cycles out of a CPU without any understanding
>> of the main bottleneck to networking performance.
>That's not a difference between PCI-X and PCI, but a difference in adapters 
>and drivers. Lookup the specs, PCI-X doesn't provide the functionality you 
>claim. To be able to test both buses properly, you need to run an identical 
>adapter in it (PCI-X happens to be backwards compatible with PCI2.x, so 
>we're lucky there). Only then you can bench both properly, as they'll be 
>using the same chip and driver.

I'm sorry, but you're wrong. Of course I've tested the
same adapters, have you? putting a PCI-X card in a 
32-bit slot is very easy to do. So stop trying to 
pretend that you can read a spec and know everything
there is to know, because you are simply dead wrong
about everything.

The fact that you can get "good results" with a PCI
but is not relevant; because the point is that you
need 3x the horsepower to get the same results as
with a PCI-X bus.

I'm arguing with a student! Yikes!

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