I also have the same notebook with the SXGA+
display(1400x1050). Right now my notebook's
resolution is set to 1400x1050. Try the 855resolution
Download the patch from this page :
Simply follow the compile and usage instruction
included on the source' gzip file.
You can also add 855resolution on your
/etc/rc.local file to start the patch before X.
Hope it helps.