I have defined featureLayers for my web map application, However it is very slow loading all polygons of mapLayers.
would increasing "maxBufferCount" or "maxRecordCount" be a partial solution?
What is the difference between these two?
How many features do you have within the layer in question? The default setting for the max # of records returned is 1000. This setting helps keep the time it takes to refresh your layer to a minimum. You can increase it, however that in theory will only slow the time it takes to refresh the data because it is now drawing more features, etc.
Short answer to your question is that NO, increasing either of the two properties will not result in quicker refresh or loading time. Depending upon what you are trying to do you can alter the min/max scales, keep the max # of records closer to 1000, and make sure the enduser can cache the layer locally, among other things. There may be a scale/level in which they only need to see a 1000 or so. You want to limit the number of features that are trying to load at one time.