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

From: Boris Spirialitious <hardcodeharry@xxxxxxxxx>
Date: Fri, 11 Mar 2005 08:37:17 -0800 (PST)

--- EM1897@xxxxxxx wrote:
> In a message dated 3/10/2005 9:52:12 AM Eastern
> Standard Time, "Thomas Edward Spanjaard"
> <t.e.spanjaard@xxxxxxxxxxxxxxxxxx> writes:
> ><EM1897@xxxxxxx> wrote in message
> news:02FB1A9B.3D7CFFE9.000424FF@xxxxxxxxxx
> >> I'd much rather hear why you don't think that the
> bus
> >> speed of the network adapter is a worthy criteria
> for
> >> hardware selection than your opinion on my
> conduct.
> >> Your reasoning is what gives you credibility; not
> your
> >> name. It seems implausible that you don't
> understand
> >> what a bottleneck a standard PCI bus is.
> >
> >Just as a sidenote, I've been able to get 12.3MiBps
> each out of two standard 
> >3c905ctx-m over a single PCI bus, with concurrent
> disk access (the 
> >controller where network data was flowing to was
> also on the same bus, old 
> >peecee). It just pays to investigate the options
> the hardware has for you, 
> >and busmastering PCI with DMA certainly ups the
> average attained speed on 
> >the 'slow' PCI bus. Of course, for Gigabit you are
> limited even by the 
> >theoretical maximum transfer rate, but there's
> PCI-X out there, as you 
> >mentioned, to alleviate that. When it comes to
> PCI-X, *all* boards are 
> >relatively expensive, not just the AMD-powered
> ones. For instance, take a 
> >look at the Tyan catalogue, it gives you a fairly
> good impression of server 
> >mainboard price differences accross the three (four
> including the Athlon MP) 
> >x86 server platforms.
> >
> >Knowing that, it sounds ridiculous to claim that
> you can get a 3.2GHz P4 
> >with a motherboard with PCI-X for under 300$. 
> 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.
> 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

Yes, I agree here. We have FreeBSD machine that 
we get device timeouts and it running at very 
high usage using 2 intel nics on motherboard. 
We find out these are only running 33mhz and 
we put 2 port intel pcix card in machine. Now it 
run 30% all day. Everything else the same. pcix is
very good and important.


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