Hello,
There are two kinds of iMac. One with Fusion and one with SSD. Both are 2TB in size. Just make sure that before you make your purchase, you select the one that you prefer (SSD or fusion). I select fusion drive, although it's pricier, but it is better. I always go to the store and purchase it instead of the website. It could be misleading sometimes on their website so I strongly suggest to visit an actual store, or at least call them and you can also place the order thru the phone.