Windows 8.1 will run smoothly if you are able to run Windows 8 on same machine. You can download Windows 8.1 and test it straight away.
How to download and install Windows 8.1 Preview for free!
Before we proceed take a look at minimum system requirements.
Windows 8.1 System Requirements:
Your PC should be running on at least 1GHz of processing power, 1GB of RAM (32-bit) or 2GB (64-bit). DirectX 9 compatible graphics chipset and 20GB of free hard-disk space. You should also have one machine running on valid/activated Windows 8.
Download and Install Windows 8.1 Preview:
If your machine meets minimum requirements for installing Windows 8.1 then fire-up your browser and open preview.windows.com
Windows 8.1 Preview is offered via Windows Store but before that you’ll have to install certain files which are only available on Windows 8.1 Official site. After installing required files, it will let you update with Windows 8.1 Preview.
Once you receive the message, click Go to the Store and follow on-screen instructions. It will download preview files from Microsoft server. Installation will begin after compatibility check. After few reboots your PC will be running on Windows 8.1 Preview!