winhost.exe is a part of the Lolaweb hijacker which means it will intermittently change your Internet Explorer settings / Desktop to the link of it's author's sponsors. "This program is usually installed through consent, however it is sometimes packaged as another product. " winhost.exe is a process which is registered as W32.Beagle.CL/K@mm Worm. "This virus is distributed via the Internet through e-mail and comes in the form of an e-mail message, in the hopes that you open its hostile attachment. " The worm has its own SMTP engine which means it gathers E-mails from your local computer and re-distributes itself. "In worst cases this worm can allow attackers to access your computer, stealing passwords and personal data. " This process is a security risk and should be removed from your system. This process is a security risk and should be removed from your system.
Non-system processes like winhost.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that your registry has suffered fragmentation and accumulated invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues.

Warning! winhost.exe is considered to be a dangerous process and should be removed. Running unused processes can increase the risk of malware infection if bugs are present. Check your computer for viruses or other malware infected files.

This process is not considered CPU intensive. However, running too many processes on your system may affect your PC’s performance. To reduce system overload, you can use the Microsoft System Configuration Utility to manually find and disable processes that launch upon start-up. Alternatively, download SpeedUpMyPC to automatically scan and identify any unused processes.