>>7
1. FYI it doesn't, unless you're using Explorer.exe.
2. FYI you can tune how much do you want to assign to the memory cache with browser.cache.memory.capacity .
3. FYI last MSIE version I used also had a memory cache. Only you can't customize how large is it, and it's small.
4. FYI even if Firefox took hopelessly more RAM, you should not use MSIE for any reason, unless you want to get raped.
5. And FYI if you do, you'll get so much shit (spyware, trojans, viruses, etc.) on your system that will take dozens of megs of RAM, I'm tired of fixing people's computers because MSIE-downloaded malware fills all their RAM and take 99% of CPU time.