Recent observations have shown that the bulk of stellar mass in our Universe was formed in distant, massive disk galaxies, called Star Forming Galaxies (SFGs) forming stars at rates up to 100 times greater than our Milky Way. Unlike our Galaxy, these SFGs are “clumpy”, i.e. most of their light and star-formation activity is confined to several giant clumps, rather than being evenly distributed. One theory is that most of these clumps form in-situ through gravitational instabilities in the galactic disks in regions where the local Toomre parameter Q is below 1, though some of them may also be merging systems. The fate of the in-situ clumps remains subject to much debate. One possibility is that clumps survive for several hundred million years, migrating from the outskirts of the disk to the centre where they coalesce to form a central bulge. A competing view is that they are disrupted over much shorter timescales due to intense stellar feedback and other processes without reaching the centre. The question of clump survival has important consequences for many issues relating to galaxy formation and evolution, including the formation of galactic bulges and the Hubble Sequence of galaxies, the quenching of star formation in galaxies and the fueling of active galactic nuclei and quasars. I will present results from a suite of 29 high resolution AMR cosmological simulations where we study the statistics of the giant clump population at 1<z<4. Nearly 2000 compact, spherical clumps are identified in ~750 snapshots. Clumps are separated into those that formed in-situ from disc instability and the ex-situ mergers. I will discuss the properties of each population and how they can be distinguished observationally. I will also show evidence for radial trends of clump properties within the disc, such that in-situ clumps become older, redder and more massive closer to the disc center, as predicted by the migration picture.