At first glance, Advanced Micro Devices Inc. (NASDAQ: AMD) and Nvidia Corp. NVDA appear to belong in the same valuation range. Both trade in the 40x forward earnings range. But that's where the similarities end – and where the pricing disconnect begins.Margins Matter — And Nvidia's Are UntouchableNvidia isn't just growing – it's a profit machine. With 58% operating margins, 86% TTM revenue growth, and a balance sheet that boasts $43 billion in net cash, Nvidia runs like Apple Inc. AAPL but grows like a star ...