can textures suffer from fragmentation?

I wrote a simple slide show type application that loads 32 1920x1080 images, and blends one in after another in a loop. All of the images are pre-loaded into textures at the start of the application.

I have noticed that when trying to render 1 or 2 of the images, the frame rate will drop considerably, It will always be the same images. If I restart the app however, the slow images will be 1 or 2 different ones.

I am running linux on a Core I5, with an integrated intel GPU.

Does anyone have any idea what could be the cause of the slowdown, and if there is a technique to avoid this?

thanks for your time.

There may not be enough memory to hold all the images on the graphics card requiring the driver to reload the textures when they are bound. This can change depending on what is happening on you system.