A reduced mass unitary frame having a cubic, spherical, prismatic, or ellipsoidal shape, a plurality of intersecting threaded boreholes that describe an spherical internal reaction chamber, and a plurality of unitary cartridges with internal fluid intensification for an ultra-high pressure, high-temperature, fluid driven press apparatus capable of reaching pressures in excess of 35 kilobars and temperatures above 1000 degrees centigrade, useful in the production of such high-pressure products as diamond, polycrystalline diamond, cubic boron nitride, and like superhard materials.