Compared to conventional amalgams, spherical amalgams:

Amalgams made from lathe-cut powders or admixed powders tend to resist condensation better than amalgams made entirely from spherical powders. Since freshly triturated amalgams from spherical powders are very plastic, one cannot rely on the pressure of condensation to establish a proximal contour for a class II restoration. Spherical alloys require less mercury than typical lathe-cut alloys because spherical alloy powder has a smaller surface area per volume ratio than does the lathe-cut powder. Amalgams with low mercury content generally have better properties. Spherical alloys also require less compaction forces and have lower setting times. Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, 12th ed page no 343