I initially upgraded my primary FF Portable install. I noticed the performance was very bad when opening web sites, moving between pages of web sites, etc. I was astounded to see the same performance when accessing a local web server that is 1 Layer 2 switch hop away, inside my home, does not serve anyone else, and has an average CPU utilization of 0%.
I installed FF 25.0.1 portable in a different directory on my local laptop hard drive. I made sure my laptop firewall would allow it access to the Internet. My personal FW is Vipre and it uses "name & location of the program" along with allow/block/prompt rules. I selected "allow".
I made sure that I did not load or install any extensions. Just a straight vanilla FF 25.0.1 portable install using the "paf.exe" file from "portableapps.com". I noticed that FF loaded Adobe Flash player plugin (version 11_9_900_152) in the background.
FF 25.0.1 portable could access the initial FF "firstpage" rather quickly. Then I opened a new tab to access "www.google.com". The URL automagically changed over to "https://www.google.com"...and then I waited. I noticed about 1 minute go by on my laptop clock before Google displayed it's page. 1 minute for Google!?!?
The PING time to Google DNS from my home FW is a steady 15 milliseconds, and to "www.google.com" is about 10 milliseconds. My own laptop is 1 Layer 2 switch hop and about 30 cable feet away from the home FW.
So I tried other web sites in FF 25.0.1 portable. "slashdot.org" had the same "slow" experience. I tried a few video streaming web sites. Same thing.
My previous experience with FF portable has always been good to exceptional. I like FF portable so much that I keep a copy loaded on a thumb drive so I can carry it on business trips to access personal email and favorite web links.
I tried 3 different portable web browsers on the same laptop: Iron Browser portable, Maxthon portable, Qupzilla portable. All are from "portableapps.com".
I pulled up the same web sites in these browsers. In every case the non-FF browsers were faster than FF, about 10-15 seconds at most when opening the mainpage of any web site.
In one case I opened the site in Qupzilla, then opened it in FF thinking it might be a delay in resolving DNS over the Internet. FF was still about 1 minute to open the same page...on the same laptop...through the same laptop FW software...through the same Internet connection.
I doubt the problem is in portable apps packaging as I have tried many other portable apps at one time or another.
I seriously think the issue is in upstream FF. I have seen similar complaints about the non-portable version. I even tried the non-portable FF 25.0.1 on the same laptop and still noticed it being "slow". I noticed one FF forum comment where a developer thought it might be a bug introduced into some resolver aspect of FF that would be fixed in a later version, perhaps FF 26 but maybe later. I tried the FF 26 portable beta and still saw the same "slow" performance.
So the question I have is this: How can I access an older version of FF portable, say FF 24 or FF 23?
While I like the portable Apps Launcher, I can't find a way to make it search, display, and allow selection of older versions of portable apps packages. For me, regressing the version of my FF portable apps install might be the best interim solution since changing to a different web browser is a hassle, not to mention going without many FF plugins that I find "necessary" to make my web browsing experience "pleasant".
I found the portable apps section on "sourceforge.net" and downloaded FF 24.0 portable. Then I loaded that version "right over the top" of the same laptop hard drive directory that I loaded a version of FF 25.0.1 portable much earlier today. I decided to load FF 24 portable that way because portable apps are upgraded that way.
In my case I am attempting to do a "regression" to an older release that is not "too old".
Once I had FF 24.0 portable loaded I accessed the same web sites that I accessed about 5 hours ago with FF 25.0.1 portable...and was there ever a difference in performance!!!!!
Under FF 24.0 portable I find web sites popping open very fast...a matter of seconds. I tried a few different web sites before making this update and the performance is consistently faster compared to FF 25.0.1. I even have a few extensions loaded, NoScript & Ghostery, and both are current.
So to me at least, the issues with FF 25.0.1 portable truly seem to be "upstream". Perhaps there are issues with the extension API in FF 25. Perhaps new bugs entered the FF 25 codebase, either as "pur error" or through an attempt to optimize or clean up previous code. I can only speculate about that stuff as I am not a software developer.
I guess it's time for me to stop updating every portable apps I use when updates occur, especially FF. Perhaps I even need to rethink donating to "portable apps" now that I see they accept something other than PayPal.