CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > CFX

4 (one core) or 2 (double core) processors?

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   February 19, 2008, 08:02
Default 4 (one core) or 2 (double core) processors?
  #1
Gen
Guest
 
Posts: n/a
Hi all! What do you recommend for parallel solving by ANSYS CFX? 4 (one core) or 2 (double core) processors; 8 (one core) or 4 (double core) processors? Thanks for your response!
  Reply With Quote

Old   February 19, 2008, 08:17
Default Re: 4 (one core) or 2 (double core) processors?
  #2
Bart
Guest
 
Posts: n/a
As most new (faster) processors are at least dual core, single or dual core is not really a choice (single core is just too old). You have to look at what processor is fastest PER core. So it's either 4 dual core used as single core or 2 dual core using 4 cores. Then the memory bus is the bottleneck (both cores need access to the same memory). Comparing quad cores to dual cores the fastest processors PER core are to my knowlegde still dual cores. We recently opted for Intel Xeon 5160 (dual cores) where only one core per processors is used. You can save money on hardware using all cores on the processors, but most of the money goes to the parallel licenses (paid per used core). The money/performance ratio is than shifted to using 1 parellel license per processor (using only 1 core per processor). I hope this makes sense.

  Reply With Quote

Old   February 19, 2008, 09:00
Default Re: 4 (one core) or 2 (double core) processors?
  #3
Dre
Guest
 
Posts: n/a
This is somewhat related. I found it very interesting.

http://www.cad-fem.de/fileadmin/file..._Platforms.pdf

Go Barcelona!
  Reply With Quote

Old   February 19, 2008, 09:53
Default Re: 4 (one core) or 2 (double core) processors?
  #4
Bart
Guest
 
Posts: n/a
Excellent link. Thanks for that. But: Go Barcelona????? Conclusion says intel Xeon 5160, taking everything into account (scaling, license cost etc). Problem with Harpertown is availability. Barcelona is good if licence costs are not an issue (free parallel codes).

  Reply With Quote

Old   February 19, 2008, 13:37
Default Re: 4 (one core) or 2 (double core) processors?
  #5
Dre
Guest
 
Posts: n/a
Well I think it's obvious that parallel computing is the new direction. Maybe not new, but getting cheaper, more sophisticated and more acceptance. You'll have to embrace sooner or later.

I'm also an AMD supporter
  Reply With Quote

Old   February 19, 2008, 17:31
Default Re: 4 (one core) or 2 (double core) processors?
  #6
Glenn Horrocks
Guest
 
Posts: n/a
Hi,

Bart is definitely right for commercial ANSYS CFX customers - the license cost for parallel licenses far exceeds the hardware cost so Woodcrest 5160 is a clear winner on this basis. However, for academic customers who pay a far lower price for the software the equation may be different and it may be better to use a larger number of slower CPUs (such as the AMD CPUs) that run better in parallel.

Glenn Horrocks
  Reply With Quote

Old   February 20, 2008, 03:15
Default Re: 4 (one core) or 2 (double core) processors?
  #7
Gen
Guest
 
Posts: n/a
Thank you all! Your advices are very useful for me.
  Reply With Quote

Old   February 20, 2008, 04:25
Default Re: 4 (one core) or 2 (double core) processors?
  #8
Bart
Guest
 
Posts: n/a
Sniff sniff, :,-( I used to be AMD supported (had one at home also). But it looks like AMD is in its final days.

CFD: one major player: Ansys CPU: one major player: Intel

so much for competition

By the way. I had a look at the CADFEM presentation from Dre. New Harpertown Xeon CPU's are available (X5460, 3+ GHz). It might tip the scale from he Xeon 5160 to the new quad cores (buy less CPU's use them as multicore and save some on hardware with the same or more speed). I'm reconsidering my upcomming purchase of a new cluster. Thanks Dre again!!!

Bart
  Reply With Quote

Old   February 21, 2008, 06:35
Default Re: 4 (one core) or 2 (double core) processors?
  #9
alterego
Guest
 
Posts: n/a
Any suggestions if it would be worth the wait for the new Xeon 5482 3.2GHz with 1600 FSB to be available?

Were heading for a new server with 2 Quadcore CPUs.
  Reply With Quote

Old   February 21, 2008, 06:48
Default Re: 4 (one core) or 2 (double core) processors?
  #10
Bart
Guest
 
Posts: n/a
The latest information I have is that the increase in bus frequency (from 1333 to 1600 MHz) doesn't help as the Xeon memory bottleneck is still there. However, the new Harpertowns Xeon's do scale better than the older 5160 (dual cores) and are just faster per core. So I would disregard the Bus frequency and go for the fastest quad core harpertown Xeon.

Bart

  Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
New densitybased solver AeroFoam giulio_romanelli OpenFOAM Running, Solving & CFD 39 October 8, 2013 03:37
Continuing User Defined Real Gas Model issues aeroman FLUENT 2 October 22, 2010 16:28
Parallel User Defined Real Gas Model aeroman FLUENT 3 October 21, 2010 16:04
Missing math.h header Travis FLUENT 4 January 15, 2009 12:48
REAL GAS UDF brian FLUENT 6 September 11, 2006 09:23


All times are GMT -4. The time now is 09:50.