In my earlier dial-up days, I used to have Netsonic and Netscape working together. I think what that utility did is have a nice-sized cache pot that Netscape fed into and ate out of during browsing, it would keep the vast majority of the cache files, which normally meant Netscape was fast-fed the necessary cache files to quickly cough the quite-often visited web sites. Any new site, any big changes by any particular web site, would have Netscape be a little slow until the cache pot caught up. Back then, Netsonic did help -- once the cache pot kicked into action.
Which one were you interested in? I'm curious.
I also have different browsers and browser profiles setup for different sites. So one profile is only used on Amazon and one is only used on Walmart. This way, the browser can hopefully pull from the cached content. And I also use addons that block ads and scripts and stuff like that.
I've looked for other accelerators, but I didn't come across anything that looked better than what I have.