The newest QB-75 uses 144xLM301H on the 90% efficient LRS-100-24 driver.
LM301H is identical to the LM301B Samsung diode, but has a protective layer against sulphurisation. The diodes can achieve 3.03 μmol/J (approx. 224lm/W) efficiency at 65mA.
At 75W, the diodes are running at 0.172A, for 187.3lm/W pre-driver, 168.6lm/W post-driver, for approximately 2.4uMol/J efficiency.
eg. Compare to HLG-65v2 2.35uMol/J (R3000)