Performant to me implies performing better against the relevant metrics. So faster, maybe, but perhaps smaller and more energy efficient too. If the context of the metrics is already understood then it seems quite a cromulent word.
"Acceptable or adequate"
When schoolteacher Edna Krabappel hears the Springfield town motto "A noble spirit embiggens the smallest man," she comments she'd never heard of the word embiggens before moving to Springfield. Miss Hoover replies, "I don't know why; it's a perfectly cromulent word".