Google's newest tablet, the Nexus 9, is set to be released sometime this October and is to replace the Nexus 7 tablet. Google's knack of commissioning their devices to other companies is fair grounds for comparisons, as in this case where the Nexus 7 was made by Asus and the Nexus 9 by HTC.
First off, the Nexus 7. The aging tablet was released on July of 2012 and by today's device standards, it's an old tablet. It has a 7-inch touchscreen with a screen resolution of 1280 x 800. It comes in three storage variants, in 8GB, 16GB, and 32GB, but doesn't come with microSD card support.
Inside the tablet is the Nvidia Tegra 3 chipset with a quad-core 1.2GHz processor, a ULP GeForce GPU and 1GB of RAM. It also has a 1.2-megapixel primary camera with video recording capabilities of up to 720p.
The Nexus 9 on the other hand will be coming with a bigger 8.9-inch touchscreen with a screen resolution of 2048 x 1536 pixels. This time, it will only be available in two storage variants, the 16GB and 32GB still with not microSD card support.
The newer Nexus tablet is powered by an Nvidia Tegra K1 chipset with a dual-core 2.3GHz Denver processor, a Kepler DX1 GP, and 2GB of RAM. The camera is improved, going from the 1.2-megapixel snapper to the 8-megapixel camera.
Both tablets run on the Android OS but the Nexus 9 comes out with the latest Android Lollipop while the Nexus 7 runs on Android 4.4.2 Kitkat. The latter, however, is planned to receive the Lollipop update.