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#1 |
Senior Member
Fatema Zandi Goharrizi
Join Date: Mar 2009
Posts: 158
Rep Power: 17 ![]() |
Hi
would any one help me with using full capacity of an i7 system on cfx runs. actually I use a system with an intel i7 920 cpu and 8 GB RAM and have cfx 11 but I just can use 4 cores on my runs and it gives errors due to licence if I'm right. thanks |
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#2 |
Member
Michiel
Join Date: Jul 2009
Location: The Netherlands
Posts: 42
Rep Power: 17 ![]() |
I assume Ansys CFX has the same license configuration as the Mechanical modules. In that case the number of cpu's is limited at 2 for one license. If you want to use 4 cpu's you should buy a second license.
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#3 |
Senior Member
Fatema Zandi Goharrizi
Join Date: Mar 2009
Posts: 158
Rep Power: 17 ![]() |
Hi
thank you I can get run with 4 core but not 8 would you please tell me if I have buy license for 8 or for 4 to run with 8 core of an i7 thanks again |
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#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,816
Rep Power: 144 ![]() ![]() ![]() ![]() |
You will need to buy additional licenses to run 8 processes. But don't bother. The I7 chip has 4 cores so running any more processes on it is bad. It looks like 8 processes on task manager as each core looks like 2 cores due to hyperthreading - but CFX does not take advantage of hyperthreading so you do not gain a useful speedup by using 8 cores.
Unless you have a dual CPU system, then you do have 8 cores. Then you just need to get that many licenses to run it. |
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#5 | |
Senior Member
Fatema Zandi Goharrizi
Join Date: Mar 2009
Posts: 158
Rep Power: 17 ![]() |
Quote:
Would you please say how I can understand that a system is dual cpu system or not? What do you mean by many licenses exactly? Thank you |
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#6 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,816
Rep Power: 144 ![]() ![]() ![]() ![]() |
Did you get a computer with 1 CPU or 2? If you can't answer this then open the box and have a look!
Parallel licenses are per-process. You need 8 to run an 8-way parallel job but only 4 to run a 4 way parallel job. |
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#7 |
Senior Member
Fatema Zandi Goharrizi
Join Date: Mar 2009
Posts: 158
Rep Power: 17 ![]() |
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#8 |
New Member
YongQiang Chi
Join Date: Jun 2010
Posts: 14
Rep Power: 16 ![]() |
I guess hyper threading may help....very little bit of CFD formance. It won't worth the price of licensing for the extra 4 virtual cores and just get less than 20% improvement.
Take a look this: http://techreport.com/articles.x/18581/14 |
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#9 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,816
Rep Power: 144 ![]() ![]() ![]() ![]() |
CFX has not been complied to use hyperthreading. Don't use it. Just leave the virtual cores sit idle or even better disable them in the BIOS.
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Tags |
8 core, cfx, cpu, i7 cpu, intel i7 920 |
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