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Fluent on Hyperthreading pentuim 4 Machines

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Old   May 6, 2004, 05:29
Default Fluent on Hyperthreading pentuim 4 Machines
  #1
Barry
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Hi People Most Operating systems see a hyperthreading P4 processor as two different processors. My question is that would we get a speed advantage in large computations if fluent is run in the parallel mode(i.e. multi-processor machine configuration) , rather than running it in its default serial mode? Thanks Barry
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Old   May 6, 2004, 06:30
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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STK
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AFTER MY RESEARCH AND CONSULTING EXPERTS, I FOUND OUT THAT THE BEST AND CHEAPEST SOLUTION IS CLUSTER (PARALLEL NODES). THE SPEED IS INCREASED ALMOST LINEARLY! SEE BENCHMARKS IN FLUENT SITE
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Old   May 6, 2004, 07:16
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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Barry
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Thanks
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Old   May 6, 2004, 12:37
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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Allan Walsh
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Not exactly your same topic, but I just got a new P4 with HT for Fluent. Only got 50% of CPU at first, but then remembered this discussion forum and turned hyperthreading off to get 100% CPU for Fluent app.

But, my new box has a 3.2 GHz processor and still only runs Fluent 38% faster than my old computer with 1.6 GHz processor. Oh well, perhaps I should just be happy that it works at all.
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Old   May 6, 2004, 14:52
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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George
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That's right, your processor may be "too fast for your computer", i.e. memory, bus, etc. Precisely for this reason it may be more cost effective to buy two older machines then one new claiming double processing speed.
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Old   May 7, 2004, 00:54
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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barry
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I did some bench marking of my own with my new p4 3.2 and i am afraid what George said is very true, i would have been better off using 2, p4 at 1.6 GHZ rather than one P4 3.2 gHz claiming to emulate 2 processors thanks again for all your comments
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Old   May 7, 2004, 01:36
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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Joern
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Do you have a 3.2 GHz machine with 800MHz bus speed and the fast main memory? I have such a machine and it is about 2 times faster than my P4 1.7 GHz with Rambus memory.
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Old   May 7, 2004, 11:38
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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Allan Walsh
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No, my upgrade was from a 1.6 GHz with 800 MHz RAMBus memory to a Dell notebook with a 3.2 GHz processor with 400 MHz DDR memory. (This gave a 38% speedup).

I know, going to a notebook wouldn't normally be the best choice for speed, but I wanted the portablity.

Having run into the issue of RAM speed a few years ago, I had checked with Fluent and their opinion was that 400 MHz of the double dynamic RAM would be better than the 800 MHz RAMBus. My recent experience would not allow me to reach the same conclusion.
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Old   May 11, 2004, 07:33
Default Re: Fluent on Hyperthreading pentuim 4 Machines
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Mattias
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Hi!

I have a question regarding the use of hyperthreading machines. I am limited to only one license and I am running a very CPU demanding calculation on a P4-HT 2.8 GHz 1Gb 400MHz DDR RAM. What would be the optimal setup for my machine? I have tried to turn of the Hyperthreading but I havenīt notice any increase in calculation speed. Sugestions?

/Mattias
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Old   May 11, 2004, 13:57
Default Re: Fluent on Hyperthreading pentuim 4 Machines
  #10
Allan Walsh
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I'm assuming that you that are running Windows? If so, use the Windows task manager to show CPU usage. With HT on, CPU usage for Fluent doesn't seem to go above 50%. With HT off, Fluent CPU usage should be 95%+, which should solve about twice as fast.
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