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Help: Need Recommendation

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March 28, 2004 8:06:24 PM

Hi,

I'm looking to put together a desktop primarily for math modeling and research, etc. Basically, I'll be running lots of math apps, with the occasional nod towards other things. Speed is imperative, and I've been torn between the FX processors and the G5 dual proc. systems. I've seen proposals that suggest that the G5 would offer the best integer and floating point math to cost ratio, but I've also seen things stating that apple has...somewhat misrepresented...the speed of the G5. Basically, I'm torn, and without these systems to actually test hands-on, I'm unsure what to do.

Am I destined to run the Athelon or the Mac?

Thanks for the help!

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March 28, 2004 9:47:55 PM

do you mean the opterons or the ahtlon fx? i assume oyu mean dual opterons. If so, well in your case, opterons and athlon 64's in general are the best performers as far as math type apps and compiling goes, as far as if its better then g5's , I would say that in all likely hood they are faster. Now I cant say that for sure, becuase there is like a blacklist on opteron vs g5 benches out there. Teh few that are are rather old but do show opterons perform better then g5's, but not much info on math or compiling type apps. Also you have to consider which form of 64 bit you want. Opterons I believe will go to 64bit alot sooner then g5's will. Yes they have the ability to perform part of the 64bit aspect, but Im nto evne sure what they call it, since its not true 64bit. I think apple wants to avoid calling anyhting 64bit, like an OS.
March 28, 2004 10:05:22 PM

AFAIK, G5 does indeed have higher theoretical FLOP ratings as any x86 cpu. For some specific, highly optimized FP apps, this matters, and G5 would make sense (things like Linpack). Its no coincidence some supercomputer clusters are built around G5 systems.

For integer math, I doubt a G5 would be as fast as a A64/FX for anything (int or FP) that doesnt fit into the cache, is even somewhat branch heavy, isnt 100% optimized or optimizeable to use all the executions units all the time, or even isnt hand coded assembly, but less than optimal compiler generated code. IOW, for most real world apps, my guess is the A64/FX would be faster than the G5 for most things, considerably faster in some. Either way, it would be a good idea to look for benchmarks on whatever app it is you will use (matlab or the likes ?)

Also, why compare a dual G5 to a single AFX ? Its not like you can't buy a dual opteron for roughly the same price as a dual G5 if you avoid the price premium of the very fastest opterons. If your budget constrained but want a SMP system nevertheless, go for a 244 or 246 system instead, it should still be faster the a dual G5 for most things, and probably cheaper as well.

= The views stated herein are my personal views, and not necessarily the views of my wife. =
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March 28, 2004 10:12:09 PM

::Nods:: Opterons, or an FX-51/53 were all part of the consideration, really. Xeons, too, if they'd perform resonably well. I just came across one claim that G5s under Mathematica are significantly faster for statistical applications, but this seems to go back and forth so much...

I sort of hope that someone with access to several different flavors of computers could run, for example, factorizations of 80-or-so-digit numbers or something equally fun on a few of these! I know people that absolutely insist G5s are the best for purely math applications, but I'd love to know if that's true before I spend a reasonably large amount of money on a computer.
March 29, 2004 1:16:48 AM

I'm not sure 80-digit calculations would require such a processor. I think you would be fine with an Athlon64 3400+, which is a lot less expensive.

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March 29, 2004 1:35:35 AM

Oh, no...that was just a simple 5-second check. Or, well, 40 second check, on this computer. I'm really much more concerned about things that might take hours or days to execute, but I really can't ask someone to do something like that, can I?
March 29, 2004 2:19:44 PM

well frankly, you can look at it this way. What kind of upgrade path will you have with a dual G5? I dont know for sure, but I doubt youll have a huge upgrade path with that route. On the other hand, if you select an opteron system, and lets say opt for the opteron 244's or 246's, then you cna expect at the very least upgrading to a opteron 250, but i most liekly youll be able to push it farther then that. the most it should take most server baords like that to support faster would be a bios update. Not to mention how the g5's could be more difficult to upgrade since they dont exactly support all the high end i/o devices. Although G5's do look nice i guess lol. if they were faster, that would be one thing, but from what ive ehard, they just arent for what you want to do.
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