Hi, If I build Python 2.7.2 and numpy-1.9.1 and run the following script import numpy c = numpy.ones((500000, 4)) mat = numpy.identity(4) r = numpy.dot(c, mat) the evaluation of the 'dot' increases the memory by app. 35 MB. If, in addition, I build numpy-1.9.1 with MKL support, and run the script, the evaluation of the 'dot' increases the memory by app. 450 MB. Is the expected? Best regards, Mads specs: Ubuntu 12.04 ifort (IFORT) 14.0.1 2013100 gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) -- +---------------------------------------------------------------------+ | Mads Ipsen | +----------------------------------+----------------------------------+ | Overgaden Oven Vandet 106, 4.tv | phone: +45-29716388 | | DK-1415 København K | email: mads.ipsen@gmail.com | | Denmark | map : https://goo.gl/maps/oQ6y6 | +----------------------------------+----------------------------------+