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[EnergyPlus_Support] Re: E+ runtime speed



Whoa!  Thanks for the detailed response!

Here are a few additional questions / clarifications:
  1. I'll try running E+ w/ virus protection shut off (and PC off the Web). I wasn't aware that McAfee or its ilk would slow down this type of process.
  2. I am told by Dell that "Core Duo" and "Core Quad" PCs are single processor machines with multiple cores (whatever that means).  I'm not sure if that makes a difference to E+; how can I tell?
  3. Do we know how much memory is required to hold the entire program? and whether additional memory helps (much)?
  4. Since I already have plans to automate the graphing of output data (numbers alone are SO cumbersome to analyze), do you care to share any details re: how you did that and what difficulties or pitfalls you ran into?
Thanks!


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Edward G. Lyon" <eglyon@...> wrote:
>
> If you are going to do a complex building, expect to wait for answers. And completely forget about other interesting software like CFD. My last E+ project with 28 zones took a couple of hours to run. I'm using purchased air and not a full HVAC system, but I have a lot surfaces and non-rectangular spaces. I routinely run a few days simulation time to check for errors and then batch several full runs to work over night...while I sleep...(3 year old 3.4 gig p4, 3 gig 800 meghz memory, raid 0 disk array)...I like sleeping so much I wrote some utilities to parse and graph my result files automatically after the E+ runs. Nothing like fresh coffee and comparison graphs with breakfast.
>
> Faster processor good - new machines are not pushing the processor speed in favor of overall operational system performance. Now a clean machine with minimal overhead extras will be faster. Vista may have more bloat than XP, but I haven't tested that. I will tell you that I have some older notebooks dedicated to data logging tasks and they are very responsive after a complete XP reload and no virus protection software running (they are not on line).
> Core Duo or Core Quad - E+ does not directly use multiple processors. However, these processors often have larger internal memory caches, so performance is improved when only one processor works with the whole cache. Multiple processors should help if you run something else like a word processor or Excel while you are waiting, which leads to don't run a bunch of stuff in the background while you are calculating.
> Big, on chip internal memory cache very good, less time spent waiting for slower external memory. When I built my computer, I had to trade away the cost of large internal cache.
> More memory good to a point, you only need enough memory to hold the entire program without using disk access virtual memory. Fastest front side memory bus with matched memory is good.
> E+ does spend a lot of time writing files so fast drives, perhaps striped, and large drive buffers probably helps a bit. Now if you are tapp __._,_.___

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