Michael's system is an APU while Pontostroy's using a dedicated GPU. The APU has a core clock of 720MHz and the RAM is DDR3 clocked at 2133MHz. The APU is also sharing the 5MB of L2 cache. The 7790 has a core clock 1050MHz and uses 2GB of dedicated DDR5 memory clocked at 1500MHz (effective clock of 6400Mhz).
The CPU and GPU cores on the APU are sharing the thermal head room, though I don't think the CPU is using much of it during these benchmarks. More benchmarks would be needed to see if it is a hardware limitation or software regression.