MySQL database structure: more columns or more rows

Question

I collect how people tag topics with categories in table like:

ID | topic_id | votes_Category_1 | votes_Category_2 |.......... | votes_Category_12

This table holds 1 row per topic and dynamically keeps count of votes on each category I dump this table every hour for history reasons. Lets say table contain 2 million rows. dumped every hour in history tables.

This solution is not flexible (that is minor because categories are pretty solid) if I want to add column Category_13, so I'm thinking about this one:

ID | topic_id | Category_id | vote_count

This solution will create 12 rows per topic, its better structured and more flexible but I'll have to dump every hour 24 million rows.

I need the best 10 topics in each category!

1. case 1: order by votes_Category_x desc limit 10
2. case 2: where category_id=x order by vote_count desc limit 10

Which one would be better JUST!!! from performance stand point:

1. To have 2 million rows with 14 columns
2. To have 24 million rows with 4 columns

Thank you