Quad-core processing has arrived at Wind Mobile with the Optimus 4X HD. For $199 on a three-year contract, the phone offers a 1.5GHz quad-core Tegra 3, a 4.7-inch HD (1,280 x 720) IPS display, an 8MP rear camera and 16GB of internal storage. Those who'd prefer foregoing the contract will find the Optimus 4X HD for $549 outright from Wind. [MobileSyrup]