Starfinder Differences

[liamfisher]

A tidbit re Spellgems:

Spell Chip modules for your computer are a great way to save a few credits for spells you might want to cast multiple times in your career, but not often enough to burn a spells known pick on. The initial module costs 10% more than the base Spell Gem, but you can reload the spell for 10% less; basically, the first time you reload it you break even, and it's 10% off from then on. 

I'm not sure whether using a Spell Chip would save you from AoOs for spell casting; using a Spell Gem seems to basically be casting a spell, but a Spell Chip might fall under using a device.

Spell Chips

It is possible to create Spell gems in the form of chips that can be slotted into a computer system. A user capable of utilizing an equivalent Spell gem with access to the computer in which such Spell chips are installed can cast the related Spells whenever controlling the computer and gains a +2 circumstance bonus to any skill check involving these Spells. Spell chips cost 110% of a Spell gem (page 224) with the same Spells. When a Spell is expended from a Spell chip, the chip itself is not destroyed, and the Spells can be reloaded into the Spell chip for 90% of the normal price of a new Spell chip.

Spell Gem

Consisting of one or more lattices of carefully arranged lines of rare metal and bits of precious stone in a silicon casing, each lattice in a Spell gem is encoded with magical writings equivalent to the casting of a single, specific Spell. Holding a Spell gem in your hand unlocks little-used portions of your mind, granting you the ability to temporarily cast the Spell encoded within the gem without using up your daily Spell slots. You must hold the Spell gem in your hand throughout the Spell’s casting time and must spend at least a standard action using the Spell gem, even if the Spell’s casting time is shorter. Each Spell stored within a Spell gem can be cast only once, after which the magic encoded within the Spell gem’s lattice is forever expended.

They both say cast - which is a significant change from Pathfinder.   So they would incur AOO.   Had this come up at Dcon with the spell gems on the Welcome boon and we agreed at the table that it was an AOO.