Question about Gigabyte Aorus GeForce RTX 2070 Xtreme

The XTREME variant is clocked a little higher by default.

The difference lies in the two cards in the chip. The XTREME has the so-called "A" chip. You can see this when you read the description of the graphics card. The A chip is simply the better chip. The non XTREME does not have this chip, which is why it is capable of lower clock rates. But both cards are very good and have no extreme difference in performance.
Greetings Yannic