So I am a new user of Linux Ubuntu 14.04 and I was wondering if its really necessary to partition my HDD. Is my boot up gonna be faster if I do partition it or is it just good practices to do it.
All hard drives have a partition table and one or more partitions. When you install Windows it will also install into a partition; in fact it'll probably create the partition for you.
By default if you buy a new hard drive, it'll just have one big partition covering the whole drive.
If you want to install two different operating systems (eg Windows and Linux) on the same disk they will usually need to be in separate partitions. This means that you need to re-partition the drive so that the first partition does not take up the whole drive, then add a second partition (or multiple partitions, if the new OS needs it).
Whenever you install any operating system it always needs to be placed into one or more partitions. The number and arrangement of partitions you need on your disk just depends on whether there are other operating systems on the same disk, and how many partitions each operating system uses.
Following up to the comments to neon_overload's answer, it is necessary that you create a swap partition for Linux, if you intent to use suspend-to-disk, also known as hibernation.
Even if you don't, it is recommended, because a separate swap partition provides at least equal and often better performance than a swap file inside another file system.