A high-performance laptop is an investment meant to last four or five years, so don't rush the decision. You want a machine that handles heavy gaming and creative work without slowing down before the hardware is actually obsolete.
Tech companies refresh their lineups annually, usually in the spring. If you wait for those new chip releases, you can often grab last year's top-tier model at a deep discount, which gives you the best bang for your buck.
The 0% intro APR is a deadline, not a gift. If you don't pay off the full $1600 before the 15 months are up, you will owe interest on whatever balance remains at the card's standard rate.