The Infinity-class Super Star Destroyer, much like the Decimation-class Super Star Destroyer, is another attempt to create a scaled-back version of the Executor-class Super Star Destroyer for the Galactic Empire. Kuat Drive Yards took a different approach than the Decimation-class and essentially just created a smaller, though still impressively large, version of the Executor-class.
The Executor-class and the Infinity-class look so much alike, in fact, that the Infinity-class is rightly blamed for much of the confusion surrounding the true size of the Executor-class. The designs that were used to deceive the then Imperial Senate into approving the first Executor models would be what Kuat Drive Yards would base the later Infinity-class on.
Like many large Imperial designs, the Infinity-class has a weakness to starfighters as its armament is meant for capital ship-scale confrontations. In such battles, the Super Star Destroyer handles itself well, but it is forced to rely on its starfighter squadrons to keep it safe from tactics like trench runs.