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-   -   P4 cpu vs i7 extreme (http://www.cfd-online.com/Forums/star-ccm/87849-p4-cpu-vs-i7-extreme.html)

mbn1454 April 30, 2011 14:41

P4 cpu vs i7 extreme
 
I am trying to compare P4 cpu and I7 CPU. My desktop computer is a Quadcore with I7 CPU (24 gig ram) and I have access to a supercomputer with thousands of P4 cores. My initial comparison shows that my desktop computer is equivalent to about 80 P4 cpus. Does this look right? Has there been such significant improvement in hardware technology since the time P4 introduced?

abdul099 May 1, 2011 06:55

There was a massive improvement in hardware technology. For example, a Xeon X5550 (2,67GHz, Nehalem architecture which is the same as an i7) is about twice as fast as a Xeon E??? (3,0GHz, Core 2architecture).

But you should not forget some other effects. When running in parallel, the communication time between processes has a big impact on the efficiency. Any additional CPU will increase the communication effort and at a certain point, it will take LONGER when using MORE CPU's. As a rule of thumb, it doen't make much sense to run a case with less than 100 000 cells per CPU, although this might vary slightly with the latency for communication.

To check how much faster your i7 is, run a case on a single core of your i7 and on a single P4 and compare the times for some iterations.


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