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Re: Intel EM64T vs. Opteron



On Fri, Oct 14, 2005 at 12:06:24AM -0700, mike wrote:
> I recently (re-)subscribed to the mailing list, I have a couple
> specific questions, and can't seem to find any good data about it, and
> would like to tap people who probably have some real-world experience
> with it.
> 
> First off, I am a user of Debian-amd64 right now - and I love it. I
> run it on Opterons. It screams.
> 
> I have a chance soon to switch out my servers, and going the Intel
> route I would be able to get a lot more bang for my buck. The website
> says that EM64T works fine with Debian-amd64, I just want to make sure
> there's no gotchas, compared to using it on an Opteron-based system.

When did xeon servers become cheaper than opteron servers? :)

> Basically, I'd be looking at an Intel 830D (3.0ghz, dual-core, EM64T)
> processor-based system, with 1 gig of ram and SATA HD vs. a
> single-core Opteron 1.8ghz (or a dual-processor NOT dual-core Opteron
> 1.8ghz) system, same HD and same RAM. Has anyone had the opportunity
> to benchmark this, or have any real experience with changing the
> underlying platform? I can build an 830D based system with dual-cores
> for cheaper than a single-core Opteron box right now (I have some
> discounts) but if the performance isn't as good as it seems it should
> be, or there's some odd things that must be done to get EM64T to work
> properly under Debian-amd64, I'd like to know that before committing
> to the hardware choice :)

I know the athlon 64 is very fast and certainly faster than the p4 I have
around here (at a much higreh clock rate).  From what I have gathered
reading this list, the P4/xeon slows down a little in general when you
enable 64bit mode.  AMDs speed up.  Given the AMD is usually faster
at mosts tasks already in 32 bit mode, the situation is not improved
(for intel) in 64bit mode.

Remember you can not compare an 830D to an opteron.  That's like
comparing an 830D to a xeon.  Rather unreasonable comparison.  Compare
it to an Athlon 64 X2 system.

> I plan on running the latest Linux kernel 2.6.x - two of my servers
> will be LVS machines and I will have a handful of webservers running
> this platform, in case you're wondering about specific usage.
> 
> Thanks in advance for any feedback!

To me the netburst architecture looked wrong when it came out.  I still
think it looks wrong and I will be happy when intel finally dumps it for
the pentium-m based architecture in their server and desktop lineups.
Until then I will buy what is the fastest (and cheapest) systems you can
get, which is AMD based systems.  Of course I haven't been buying dual
core, which do seem rather pricey relate to single core.

for example:
Asus A8V Deluxe $132cdn
AMD Athlon 64 X2 3800 $440cdn
AMD Athlon 64 X2 4800 $1066cdn
2 x 512MB DDR400 $122cdn
2 x 1GB DDR400 $330cdn
Total is $694cdn (3800 1GB) to $1528cdn (4800 2GB)

Asus P5LD2 $153cdn
Intel Pentium D 820 $314cdn (2.8GHz)
Intel Pentium D 840 $670cdn (3.2GHz)
(I am ignoring the extreme edition as being silly expensive)
2 x 512MB DDR2-533 $140cdn
2 x 1GB DDR2-533 $280cdn
Total is $607cdn (D820 1GB) to $1103cdn (840D 2GB)

Video, HD, case, etc should be similar between systems and hence not
relevant.

An X2 3800 = 2xAthlon64 3200 (which in my experience is easily faster
than a 3.2GHz P4).  An X2 4800 = 2xAthlon64 4000.  The 4600 is the same
but with half the cache.

Given the more efficient memory interface of the athlon64 x2 than the
shared FSB 830D, and that the 3800 is a dual of a cpu that already is as
fast as the single core in the 840D, it is actually fair to compare the
X2 3800 to the 840D (which costs more of course).  The 820D and 830D
might be cheaper, but they will also be slower for probably just any any
task you throw at them.

Enough ranting from me. :)

Len Sorensen



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