The few extra GHz are not that important. The main things you lose with Pentium vs. i3 are Quick Sync and Hyper Threading. G620 or i3-2100 will both be very good citizens with respect to power even if they are not T-variants. If money isn’t an issue, spring for the i3, otherwise, you can get by with the Pentium. If you are doing commercial skip analysis, at least get i3, if not i5.
Places to skimp will be in memory and SATA3 if budget is an issue. You’ll benefit from an i3 more than an extra 4GB or SATA3 SSD.
