[nukes]

I normally use bz2 for big files. More out of habit than anything else. It did a 1573mb file to 1271mb on default settings. That was like 80% of the original size. For you that would take the file to 631mb. But sums like that aren't to be trusted as the compression isn't exactly linear.
RAR would do it better out of those two. I think WinRAR only has like a 30-day eval time (same as winzip, but winrar stops working afterwards) but the command line tools are fine.