Formula for RlLib resource requirements

I still don’t get the gist how Rllib determines resource requirements.

For tune I figured it out to the following formular:

num_samples * ( (num_workers * num_cpus_per_worker) + (num_workers * num_gpus_per_worker))

Now telling you that scenario for Rllib.

Feasible:
(Ok, with multiple raylet OOM warning messages, but it terminates with the final result message.)

if __name__ == "__main__":
    ray.init(num_cpus=12, num_gpus=1)
    config = (
        ppo.PPOConfig()
        .environment("CartPole-v1")
        .rollouts(num_rollout_workers=2)
        .resources(num_cpus_per_worker=6, num_gpus_per_worker=0.5)
        .framework("tf2", eager_tracing=True)
    )
    algo = config.build()
    algo.train()
    print("One iteration done")

Infeasible:
(Turning into endless loop)

if __name__ == "__main__":
    ray.init(num_cpus=12, num_gpus=1)
    config = (
        ppo.PPOConfig()
        .environment("CartPole-v1")
        .rollouts(num_rollout_workers=3)
        .resources(num_cpus_per_worker=4, num_gpus_per_worker=0.3)
        .framework("tf2", eager_tracing=True)
    )
    algo = config.build()
    algo.train()
    print("One iteration done")

What is the difference between (34,30.3) = (12,0.9) and (26,20.5)=(12,1) configuration?