Personally, I would have 2 hard drives. I would put the OS on the bigger non-SSD drive. This would give you plenty of room for other games, storage, etc.
Then, I would install IL-2 on a small SSD. You would see a marked improvement in certain aspects of the game.
*Standard hard drives are so inexpensive these days and a single 60GB SSD would fill up so fast you would need another HD anyway. Heck, my IL-2 folder alone is around 25GB...and that's unmodded...
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