OpenLayers: given the same number of Features, is it better to have one big Layer or several small ones?

Given a certain amount of features that sometimes don’t fit all together inside the current window, is it better to use one single/few big layer/s or it it better to split the features among more smaller ones?

For example right now I’m rendering everything using three layers, one for all the icons, one for all the lines and one for the background. But relatively often zooming in and zooming out causes the background to lag.

Should I split the features in multiple small layers instead?