[TRNSYS-users] PC capacities to run faster?

[Janne Paavilainen]

Hi!

Some guidelines:

In general, it's the combination CPU+Motherboard+RAM that defines the 
total "speed" of your PC. The key figure here is memory read/write 
speed, usually given as MB/s. The bottle neck can be any of the three 
parts of the combination. So be aware that upgrading CPU will do no good 
if the MoBo bus or the RAM turn into bottle necks.

CPU and motherboard
As fast as your budget allows, direct relation between CPU speed and 
simulation time. TRNSYS16 does not have multi-core support. However, you 
can run e.g. two simultaneous simulations on a dual core CPU halving the 
total needed time if the simulations are independent (i.e. if you don't 
have to wait for the results of one to start the other). Dual core is 
also useful if you need to use the work station for normal use when the 
simulation is running. I'd guess you can run 4 simultaneous simulations 
in a quad core, but I never tested that. Also don't know if the time 
divider will really be 4 or less in that case.

RAM
TRNSYS is no memory hog, usually a model takes up memory in the order of 
a few MB to tens of MB. So if you don't have any other memory eating 
software connected to your TRNSYS model this is not an issue.
But... be aware that memory speed can be a bottle neck, you have to 
carefully match your RAM to the CPU and mother board bus speeds if you 
want to optimize PC performance.

HD
Hard disk should not be a bottle neck. Even if it seems that during a 
simulation the HD light is blinking all the time, the real HD idle time 
is probably >95%. If you're producing output files in the order of tens 
of MB (or even some hundreds of MB) for a long sim you should have no 
worries.

Cooling
TRNSYS sucks up to the CPU 100% producing a lot of heat when your 
simulation takes hours. You have to take care of cooling not to burn the 
CPU or destroy your hard disks. If you plan to run simultaneous 
simulations on multi-core I would monitor the computer temperatures on a 
test run to be sure that the cooling is sufficient before leaving the 
machine running for hours by its own. If it's in a small room, leave it 
ventilated.


Cheers
Janne

PS. When I built my home recording studio PC about 1.5 years ago, the 
Intel CPU were using a lot less electricity and thus also producing a 
lot less heat than the AMD processors. Don't know if that's changed.
PS2. You can get fast computers from e.g. Dell but they cost a lot more 
than building it yourself. On the other hand, building a fast PC from 
scratch, choosing components and getting it running (and eventual 
overclocking) may be very time consuming (days...) and you have 
little/no support when you run in to trouble. I would not be able to 
justify building a PC on my work time.
PS3. Check your current PC benchmark (memory read/write) with some free 
software and compare performance to new CPUs (within your budget range) 
somewhere on the net, so that your not ending up wasting a lot of money 
and time for e.g. 20% shorter simulation time.
PS4. Overclocking forums on the www are good info sources if you plan to 
build the PC yourself.

-- 
-------------------------------------------------------------
Janne Paavilainen 
MSc, Doktorand
Forskare inom Energi och miljöteknik
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Solar Energy Research Center SERC
Högskolan Dalarna
SE-781 88 Borlänge
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tel +46 (0)23 778728
fax +46 (0)23 778701
e-mail: jip at du.se
-------------------------------------------------------------
www.du.se
www.serc.se
www.eses.org
www.uni-kassel.de/fb15/ite/solar/solnet/
-------------------------------------------------------------



Francois wrote:
>
> Hi all,
>
>  
>
> I am running a simulation with TRNSYS that takes almost 24h because of 
> a heavy component and a small timestep. I don't want to have to change 
> my parameters because I need accurate results.
>
> Currently, I have got a DELL PC with an Intel Pentium 2GHz and a RAM 
> of 1GB.
>
>  
>
> I am willing to upgrade to a new computer running maybe 3 or 4 time 
> faster...
>
> Could somebody tell me what equipment would be worth to buy, or even 
> what kind of processor and memory should I consider?
>
>  
>
> Thanks for some help.
>
>  
>
> Francois
>
>  
>
> ------------------------------------------------------------------------
>
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