I would take the i3 because the pentium only supports a maximum of 8gb ram with a speed of 1333 and only one pci expersse 4x slot. The i3 is also a little bit faster but consumes more power. Here you can can compare them in detail:
http://ark.intel.com/de/products/81074/Intel-Pentium-Processor-N3530-2M-Cache-up-to-2_58-GHz
http://ark.intel.com/de/products/65697/Intel-Core-i3-3217U-Processor-3M-Cache-1_80-GHz