Breakdown of Этот компьютер быстрее, чем тот.
компьютер
computer
этот
this [f: эта, n: это]
быстрый
fast, quick
тот
that
Questions & Answers about Этот компьютер быстрее, чем тот.
How did we get the word быстрее?
Быстрее is the comparative form of the adjective быстрый (fast). To make the comparative for many regular adjectives, you remove the normal ending (like -ый) and add -ее. Because it acts as a predicate here (describing what the computer "is"), this form is frozen and doesn't change for gender or number.
Wait, doesn't чем mean "with what"? Why is it here?
You are right that чем is the instrumental case of что (what). However, here it is doing a completely different job: it acts as a conjunction meaning "than". It is used to compare two things, just like in English.
Why do we use тот at the end of the sentence?
Тот means "that" or "that one". Just like этот (this), it has to match the gender of the noun it refers to. Since it points back to компьютер, which is a masculine noun, we use the masculine form тот. If we were comparing cars (машина, which is feminine), it would be: Эта машина быстрее, чем та.
I've seen comparisons without чем. Can we write this sentence differently?
Yes! You can drop the word чем entirely if you put the second object into the genitive case. So, you could also say: Этот компьютер быстрее того. Both versions mean exactly the same thing and are very common.