The One X+ runs a 1.7GHz quad-core Nvidia Tegra 3 AP37 processor, an improvement on the quad-core 1.5 GHz processor in the One X, which launched earlier in the year. This means that the phone is 27% faster than its predecessor, according to internal testing by HTC.
The Long Term Evolution (LTE), or 4G, version of the One X+ is claimed to be 67% faster than the equivalent One X, while the inclusion of a 2100 mAh battery gives up to 50% (6 hours) more talk time.
Storage has increased to 64GB, and the 8MP camera has been improved with an f/2.0 wide aperture lens, backside-illuminated (BSI) sensor, Video Pic, HDR and one-press Continuous Shooting.
Alongside unveiling the One X+, HTC has also announced upgrades to Android Jelly Bean for the HTC One X and HTC One S.
After HTC Sense 4 debuted with Ice Cream Sandwich on HTC handsets, the upgrade to Jelly Bean brings the new Sense 4+ overlay to high end HTC handsets.
The revamped software offers various additional features, such as HTC Get Started, a web service that enables customers to more easily set up their phone from a desktop web browser.
Other additions include a Self Portait system in the front-facing camera that detects the human face at various angles and then applies "subtle enhancements" to skin and eyes.
Galleries of images will now offer two additional views based on where or when the images were taken. The 'Tap and Go' system in the Beats audio allows premium HTC phones to be connected to Beats speakers with just a tap.
"We are taking the HTC One X to a new level with the introduction of the new HTC One X+," said Peter Chou, the chief executive of HTC Corporation.
"Our customers will have super-fast browsing, an even better camera and more immersive entertainment with Beats Audio."
The HTC One X+ will be available in Europe and North Asia from October, and in South Asia from November 2012. Pricing has not yet been announced.
The Android Jelly Bean with HTC Sense 4+ update is scheduled to begin rolling out for the HTC One S and HTC One X from October.
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