No, there is no difference at all.

Slight difference. Not hugely important but if you are an English teacher or you have some burning desire for the slight nuances of meaning/usage... <1> He finished the race before I did, even though he's slow. <2> He finished the race before I did, despite the fact (that) he's slow. RE: sentence <2> there is actually an omitted conjunction there, it's a quirk of informal speech. The whole phrase is usually "despite the fact THAT" but in your example, a complete sentence follows (he is slow) so we leave out the conjunction "that" because in informal speech there is a tendency for shortcuts where possible... If anyone has Swan's Practical English Usage, there is a section on THAT; omissions (as conjunctions and as relative pronouns) A related example: I forgot you were coming! I forgot (that) you were coming!