I just had the same thing on a 9560 with the latest firmware / BIOS. My cap was at 28x multipllier, so not massive but enough to cripple my audio DAW performance at high CPU demands.
Turns out it was caused by undervolting the CPU cache! I applied a typical -120mv offset to both CPU core and cache using Throttlestop. The cache offset caused the multiplier limit on battery - removing it (CPU core offset can stay in place) allowed me to hit the 34x multiplier on battery.