High speed steels, e.g., M50, are well-known bearing materials. They combine high strength and high wear resistance thanks to a high hardness and the presence of very hard carbides. The quest for increased performance, for instance for motors with high efficiency and low fuel consumption, requires stronger and lighter components. The strength of high speed steel produced by conventional metallurgy (conventional HSS) has been improved by advanced elaboration methods such as vacuum induction melting (VIM) and vacuum arc remelting (VAR). However, further improvements can only be achieved through advanced metallurgical processes that enable the design and production of even more highly alloyed steels. Powder metallurgy is ideal for the production of very high alloyed steel. The extremely high solidification rate hinders segregation and enables the production of alloys that are not possible to obtain through conventional metallurgy. High integrity powder metallurgy (HIPM) includes state-of-the-art technologies such as electro-slag heating (ESH), gas atomization and hot isostatic pressing (HIP), followed by forging and rolling. Gas atomization of the ESH-refined molten steel results in an extremely clean, fine, and homogeneous microstructure. The HIP, followed by forging and rolling, yields a fully dense material. High speed steel produced by HIPM exhibits superior mechanical strength and fatigue properties than conventional HSS does. This investigation has focused on comparing HIPM high speed steel with conventionally produced material, such as M50 VIM–VAR for bearing applications. Mechanical properties such as impact toughness, fatigue strength, and rolling contact grooving fatigue have been investigated. Special attention has been paid to the influence of material cleanliness and carbide size on mechanical properties.