Intel equipped its processors with SSSE3 in 2006 but AMD didn't adopt this instruction set until the introduction of its Bulldozer CPUs in 2011. This means gamers with a Phenom II or older processor will be unable to play Destiny 2. Additionally, the Llano APU, which was also launched in 2011, lacks support for SSSE3 so gamers with that chip are also unable to play Destiny 2.
Bungie says they're trying to come up with a fix, but points out that these processors fall outside the minimum specifications. The minimum specs of the game require an Intel Core i3 3250 3.5 GHz or Intel Pentium G4560 3.5 GHz, or an AMD FX-4350 4.2 GHz processor.
Oddly enough, some gamers with pre-SSSE3 systems claim they had no issues with the beta version of Destiny 2.