Please describe the problem:
When I try to open not so big file (say 60MB), gedit eats a lot of my memory, system responses are quite slow and when gedit window appears, it takes quite a long time to display the whole file.

Steps to reproduce:
1. $ cat /dev/urandom | strings --all | dd of=/tmp/big.txt bs=1k count=60000   # do not know better way how to generate such a file :)
2. $ gedit /tmp/big.txt

Actual results:
gedit eats more then 70% of 2GB RAM and it takes more then 5 minutes before whole file is ready

Expected results:
gedit should use much less memory and CPU

Does this happen every time?
always

Other information:
These bugs could be related:

Bug 172099 – it takes too long to open big files
Bug 486393 – Opening a large file crashes gedit
Bug 489356 – System unresponsive when opening huge files in gedit

Maybe also these:

Bug 456667 – crash in Text Editor: opening a 1.6GB AVI file
Bug 462970 – crash in Text Editor: opening a large file (~1...
Bug 493274 – crash in Text Editor: open a file.