I've only used i3 machines occasionally and find them rather frustrating and slow, even just doing simple MS Office and browser things, but this may be as much to do with other components being low end also.
The i3 is specifically marketed by Intel as an "entry-level" chip. So that comes with all the wonderful entry-level "features" to be expected at that level such as lo/no cache, poor integrated graphics etc.
So 70% of the slowness comes from the Intel chip, the other 30% comes from the "other low-end components" you mention.
The only thing worse than an i3 are the Celerons and Atoms of this world... which are truly gruesome !