I did have a few problems years ago when I tried to multi table on my laptop which led to crashes etc. I usually only spend around £400 on a basic laptop, but it does what I need, and now I only play single tables I have no problem.
If you are planning to multi table I would suggest getting a Tower system with Gaming in mind so that you have the ability to run multiple tables, also having a separate monitor will give you the added advantage of having as big a screen as possible, to have the tables in a tile format and all screens are visible at all times.
I had fewer problems when I used my tower system, but unfortunately my wife objected to it being in the living room as it took up so much room and I made the mistake of going down the laptop route.
It kept her indoors happy, anything for a quite life.
When the fun Stops, STOP!