> grep GHz /proc/cpuinfo
model name      : Intel(R) Xeon(R) CPU E31240 @ 3.30GHz

> ifort --version
ifort (IFORT) 14.0.2 20140120
Copyright (C) 1985-2014 Intel Corporation.  All rights reserved.
[Phi: this compiler uses avx instructions by default in parallel mode]
> ifort -O3 -parallel -par_threshold90 -DARDIM=4000 matmul.F
> OMP_NUM_THREADS=1 ./a.out
 Running with array sizes        4000 by        4000
  dtime:     0.120   real time:     0.134    init
  dtime:     4.700   real time:     4.690     ikj
  dtime:     4.670   real time:     4.683     jki
 Sum of elements:           105312418747995.250
> OMP_NUM_THREADS=4 ./a.out                                                           Running with array sizes        4000 by        4000               
  dtime:     0.290   real time:     0.073    init
  dtime:     5.360   real time:     1.345     ikj
  dtime:     5.340   real time:     1.336     jki
 Sum of elements:           105312418747995.031
> ifort -O3 -parallel -par_threshold90 -DSIZEARGS -DARDIM=4000 matmul.F
> OMP_NUM_THREADS=1 ./a.out                                                           Running with array sizes        4000 by        4000                          
  dtime:     0.130   real time:     0.137    init
  dtime:    11.650   real time:    11.651     ikj
  dtime:    11.610   real time:    11.615     jki
 Sum of elements:           105312418747995.297
> OMP_NUM_THREADS=4 ./a.out                        
 Running with array sizes        4000 by        4000
  dtime:     0.220   real time:     0.058    init
  dtime:    12.900   real time:     3.225     ikj
  dtime:    12.880   real time:     3.223     jki
 Sum of elements:           105312418747995.016
> ifort -O3 -mavx -DARDIM=4000 matmul.F
> ./a.out                                                                             Running with array sizes        4000 by        4000
  dtime:     0.120   real time:     0.132    init
  dtime:     7.160   real time:     7.156     ikj
  dtime:     7.090   real time:     7.107     jki
 Sum of elements:           105312418747994.937
> ifort -O3 -mavx -DSIZEARGS -DARDIM=4000 matmul.F
> ./a.out
 Running with array sizes        4000 by        4000
  dtime:     0.120   real time:     0.128    init
  dtime:     8.710   real time:     8.710     ikj
  dtime:    35.370   real time:    35.400     jki
 Sum of elements:           105312418747995.000

> ifort --version
ifort (IFORT) 13.1.2 20130514
Copyright (C) 1985-2013 Intel Corporation.  All rights reserved.
[Phi: this compiler uses avx instructions in parallel mode only via mkl]
> ifort -O3 -parallel -par_threshold90 -mkl -DARDIM=4000 matmul.F
> OMP_NUM_THREADS=1 ./a.out
 Running with array sizes        4000 by        4000
  dtime:     0.130   real time:     0.134    init
  dtime:     5.440   real time:     5.442     ikj
  dtime:     4.540   real time:     4.548     jki
 Sum of elements:           105312418747995.250
> OMP_NUM_THREADS=4 ./a.out
 Running with array sizes        4000 by        4000
  dtime:     0.220   real time:     0.059    init
  dtime:     6.730   real time:     1.877     ikj
  dtime:     5.170   real time:     1.292     jki
 Sum of elements:           105312418747995.031
> ifort -O3 -parallel -par_threshold90 -mkl -DSIZEARGS -DARDIM=4000 matmul.F
> OMP_NUM_THREADS=1 ./a.out
 Running with array sizes        4000 by        4000        
  dtime:     0.130   real time:     0.133    init
  dtime:     5.660   real time:     5.658     ikj
  dtime:     4.660   real time:     4.663     jki
 Sum of elements:           105312418747995.250
> OMP_NUM_THREADS=4 ./a.out
 Running with array sizes        4000 by        4000
  dtime:     0.210   real time:     0.055    init
  dtime:     7.250   real time:     2.304     ikj
  dtime:     5.290   real time:     1.323     jki
 Sum of elements:           105312418747995.031
> ifort -O3 -mavx -DARDIM=4000 matmul.F
> ./a.out                              
 Running with array sizes        4000 by        4000
  dtime:     0.120   real time:     0.132    init
  dtime:     7.230   real time:     7.234     ikj
  dtime:     7.270   real time:     7.269     jki
 Sum of elements:           105312418747994.937
> ifort -O3 -mavx -DSIZEARGS -DARDIM=4000 matmul.F
> ./a.out                                         
 Running with array sizes        4000 by        4000
  dtime:     0.130   real time:     0.136    init
  dtime:     8.500   real time:     8.503     ikj
  dtime:    35.530   real time:    35.562     jki
 Sum of elements:           105312418747995.016

[Phi: in single threaded mode both compilers require -mavx flag]