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Often enabling QoS, using defaults, on any 2960/3560/3750 will cause additional drops.
Even without QoS, the 2960/3560/3750 series don't have a lot of buffer space and are all prone to transient congestion drops. One possible reason, you might see more drops on a 3750E vs. a 3750G, the former might have a 10g uplink, the latter having 10g is very rare. If you have a 10g link, it can more easily overrun a gig egress port.
Can drops be mitigated? Often they can. The 3750s have 2 MB of RAM for each bank of 24 edge ports and for the module ports. Moving your busy ports onto different banks might help. Also, buffer tuning, when QoS is enabled, might reduce drops too. (I've had good success with more of shared pool approach [more like the 3550s] rather than a reserved per interface approach, for reducing drops.)
