I would like to place each item more close to each other, that is, decrease the line spacing but I didn't find any useful thing.
\begin{itemize}
\item Processor: Intel Core \textsuperscript{TM} i5-5300U CPU @ 2.3GHz
\item RAM: 8 GB
\item OS: Windows 7
\item Computer: HP840G
\end{itemize}
in the preamble include \usepackage{enumitem}
and then you can cutsom set the itemsep in the itemize like this: \begin{itemize}[itemsep=20pt]
or no item seperator \begin{itemize}[noitemsep]
.