[Radiance-general] Re: multiprocessor systems, Radiance, and you

[Zack Rogers]

Hello,

I've been using several dual processor systems for the past year or 
so...I thought I'd add my 2 cents.

Our IT guy built my machine using a Tyan motherboard and 2 - 1.8 GHz 
Athlon AMD MP.  I'm told by our IT tech guy that the AMD processors are 
faster doing these floating point calculations than the Pentium III or 
IV counter part.  He says the Pentium's fairly new MMX instruction set 
is great for new multimedia programs coming out, but the program has to 
be able to take advantage of this MMX instruction set.  I guess 90% of 
the programs out there are not designed to use the MMX and require the 
older 387 instruction set.  So, the new Pentium's can revert back to the 
387 instruction set but are slower than the AMD counter part when doing 
so.  So until a version of Radiance is compiled that takes advantage of 
MMX, I believe AMD processors will perform better.  I am not an expert 
on all this, I hope I have not misstated anything as I am just passing 
along what was told to me, but if you have any other questions on the 
specifics of our dual processor machines please feel free to ask.  We 
have built several for both Radiance and CFD modeling and so have some 
experience with this.

My machine has been working great for me.  I run Windows NT on it but I 
also use several other Dual Processor machines running Suse8.0.  On both 
OS's, the Radiance simulations run on only a single processor.  I will 
typically have numerous parametric designs, and so this works for me.  I 
will usually just load up each processor and run them in parallel.  I'm 
sure there is a way to get them to run in series, but I too have much to 
learn about Radiance and have no idea how.  I would recommend the Suse 
OS, it has worked great for us, although I have no experience with any 
other Linux OS so I have nothing to compare it to.  Radiance did compile 
easily on it and it runs great.  Radiance does run as a friendly process 
on it, sharing the processor with other programs, which is nice.  Our 
CFD programs our processor hogs.

Hope this is of some help!
~Zack

-- 
Celebrating 20 Years of Improving Building Energy Performance

Zack Rogers
Staff Engineer
Architectural Energy Corporation
2540 Frontier Avenue, Suite 201
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