Auto save with an array issue

So I'm attempting to create an auto save system for my game which saves the game every 5 seconds or so... The issue is that the array for my world data is already over 1MB in size and growing, and when I save the array, the game "hiccups" for a split second while it's saving. There's a noticeable lag which is really unacceptable for any game every 5 seconds of play.

So is there any trick or way of auto saving an array while avoiding this issue? Or am I going to be forced to having the player manually save their game? How do other games save data on the fly without it causing lag issues?

It's a number array that's like 1500 X dimension and 10 Y dimension.

There's just no way to currently save like a small bit of data at a time. It's save the whole file or nothing.

Saving at app end could work but then if the game or computer crashes you'd lose hours of progress.

It appears the Ini++ object can save/load objects including it's variables and strings... Only issue is that it appears the latest version of the extension the object load isn't working. Anyone know who I'd contact about getting it fixed?

Nevermind, something about the folder pathing was screwing it up. I got the saving/loading of objects working with Ini++... I'll test to see if this is a viable solution