If you want to compare apples to apples (the exact same size and speed on laptop as a desktop), then you will need more money for your laptop apples. Laptops are more expensive than desktops and generally speaking, if you want something a laptop to equal what you can get in a desktop, be prepared to spend more money.
I am unfortunate to be the representative in my department to order new computer equipment. My employer requires laptops replaced every two years and desk tops every 4 years... that kind of gives you an idea of comparison.