UltraEdit handles multiple files at once, even if they are multi-megabyte files. It is Disk based and only requires a small amount of memory, even for very large files. UltraEdit-32 is designed for Windows NT and Windows 95, and UltraEdit is designed for for Windows 3.1. One fee allows use of both products. This sites been around a long time, and they do a great job.
Software is rated, and easy to find, but some days the site seems a little slow.
Literally hundreds of programs are available. You get mainframe quality tech support, and the best tools all from one source. Well organized, and fast. However, you may have to wade through a ton of end user software before you get to applications that you may actually find useful. NT Shareware One of our favorite sites.