I am doing a project where I've robot which will be using kinect + ROS for Simultaneous Localization and Mapping. Which board should I use? I've heard that Raspberry pi , beaglebone are not sufficient.
There are several platforms possible, depending on your experience level and needs.
If you are comfortable working with the Raspberry Pi or the Beagle Bone... the next step up might be the Jetson TX1 or TX2 from Nvidia. Please note that the default install of OpenCV4Tegra does not include the slam modules, so you will have to install OpenCV from source if you plan on using that library for SLAM/SIFT. ROS can be installed on the Jetson following this guide.
Qualcomm also makes the snapdragon line or processors and there are many other chips out there, too.
Please review the guidelines for your question since it seems highly opinion based. Consider rephrasing/asking a more specific, technical question.
Nvidia Jetson TX2, I have one and it is pretty fast. There are so many boards, I prefer ARM for prototyping, but you can use notebooks, Intel IoT boards, Mbed like Nucleo, small motherboards. It is huge the number of possibilities.
Kinetic does not need much processing for create a point cloud so you don`t need nothing fancy.