Image load time unstable

[bearpaw]

Hi, when I run my code (modified from fb.resnet.torch with my own dataset) on machine A (Ubuntu 14.04 + Titan Black), everything is fine. The training log is as below

where Time is the image loading time + forward/backward time, and Data is the image loading time only.

However, when I run the same code with the same setting on another machine (Ubuntu 14.04 + Titan X), the image loading time is very unstable

Does anybody have any idea about this issue? Thanks very much!