It may not be making a smartphone this year, but Amazon is still going all-in on its Kindle Fire tablet lineup. The company has just announced two new Kindle Fire HDX tablets, one with a 7-inch 1920×1200 screen and another with an 8.9-inch 2560×1600 display—these screen sizes and resolutions are enough to give Google's Nexus tablets a run for their money, and their 2.2GHz Snapdragon 800 SoCs and 2GB of RAM should represent a substantial performance upgrade over the Texas Instruments SoCs in last year's models.

Amazon is also trumpeting thickness and weight reductions over the tablets the company announced at its Kindle Fire press conference last year. The 7-inch model is now 0.35 inches thick and weighs 10.7 ounces (down from 0.41 inches and 13.9 ounces) and the 8.9-inch model is 0.31 inches thick and weighs 13.2 ounces (down from 0.35 inches and 19.2 ounces). Dual-band, dual-antenna 802.11n and front-facing cameras come with both tablets, while the 8.9-inch model also picks up an 8MP rear camera.

As ever, our enthusiasm for the specs is tempered by the fact that the hardware is still a one-way ticket to Amazon's ecosystem: Amazon's newly christened Android 4.2 fork, Fire OS 3.0 (codenamed "Mojito"), comes with new features but continues to eschew Google Play and its apps and media libraries in favor of Amazon's (while I can download a Kindle app on my Nexus 7, I can't get to Google Play or the Nook or Kobo book libraries on a Kindle). The new operating system most prominently includes a new e-mail client, upgrades to Amazon's Silk Web browsing engine, and a new "Mayday" button that promises real, in-person tech support within 15 seconds of being pressed.

When asked if the company would be updating any of its previous tablets with the new software, an Amazon spokesperson told us that the company had no specific information to share but that Amazon has "a long history of bringing new features to previous devices whenever possible." Owners of the original Kindle Fire may have quibbles with Amazon's claim there, but hopefully older devices won't be left in the cold this time around.

Both HDX tablets can be purchased with or without Amazon's "Special Offers" advertisements, with or without Verizon or AT&T LTE connectivity, and in 16GB, 32GB, and 64GB capacities. The 7-inch HDX model starts at $229 and will start shipping October 18th, and the 8.9-inch model starts at $379 and will start shipping November 7th. Last year's 7-inch 1280×800 Kindle Fire HD tablet will still be sold with Amazon's new operating system and a slightly faster 1.5GHz OMAP4 SoC starting at $139 for an 8GB model—this upgraded model goes on sale October 2nd. All three models can be pre-ordered from Amazon starting now.