Is "performance on a task" grammatically correct?

To my ear, "performance on a task" sounds fine on its own but when I try and place it in a sentence st the object rather than the subject it sounds ackward.

"Performance on the classification task" definitely does not sound okay. It's not that it is technically wrong. It's that it sounds like the person doesn't know how to say what they want to say. It sounds roundabout. Too indirect and wordy.

Your second choice is far, far better but feels a bit off still. I would go with "Both approaches lead to higher classification performance" if it is easily understood you are already talking about the network.

I personally, would go with either:

• "Both approaches improve network classification performance."
• "Both approaches improve the network's classification performance."

Depending on the how specific you are about the particular network in your topic.