`convert`ing *.gif to file.pdf hangs/freezes the system

I've 415 gif files in a directory and trying to make a single pdf of them by using the following command: convert /path/to/*.gif file.pdf But it cause for hanging/freezing of the entire system. In other words it makes the system very slower and I've to Ctrl+c (kill) the process (which also consume some time for stopping). How do I face this issue/problem? Is there any better/alternative mechanism (command/program/work-around) for doing this task? Note: I'm working on my simple Desktop PC (3+3 GHz P4 processor and 1GB og RAM) with Trisquel GNU/Linux 7.0 LTS. The convert program is a member of the [ImageMagick](http://imagemagick.org/) suite of tools.