Hard to say with an unbranded PSU. 450W is easily enough for that graphics card in a normal system, but the question is whether that unbranded PSU can really deliver 450W (or anywhere close to it) reliably.
Your system won't draw anywhere near 450W. Not even 300W. So there's a decent chance it'll work alright. But a noname PSU is never truly safe, so I'd recommend replacing it with a reliable brand PSU at some point.