Ed Bott has written up a hopeful but ultimately misguided post about a supposed Internet Explorer 8 performance fix. There's just one problem. It doesn't work. So please don't write me about it--surprisingly, no one has, so far--as it just doesn't work.
Fortunately, you don't have to take my word for it, as there are far more technical people out there than I, one of whom, my Windows 7 Secrets co-author Rafael Rivera, has the chops needed to tell the difference between wishful thinking and empirical fact.
So what is actxprxy.dll? Well, as Ed pointed out, the library is pretty obscure and has almost zero documentation. The fact it came from back in Internet Explorer 3/Office 97 days doesn’t help either. From what I’ve been able to gather via method of poking, actxproxy.dll is a proxy for software to communicate with out-of-process ActiveX/COM objects.
… and regsvr32? Regsvr32 is a very simple tool that simply loads a binary and calls its DllRegisterServer, DllUnregisterServer, or DllInstall function, depending on the switch you pass it.
I sat down and spent some time disassembling actxprxy.dll… and to no surprise the DllRegisterServer function simply calls NdrDllRegisterProxy with a bunch of interfaces to register. I also conducted a few experiments. First, I exported portions of my registry to file and tried re-registering the DLL. After re-registration, I used WinMerge to compare the two files and noticed zero (relevant) changes. Second, I tried unregistering the DLL. Internet Explorer immediately malfunctioned and ultimately ceased to work at all, indicating the library had to have already been registered.
As a result of some pretty simple testing, I’ve come to the conclusion that reports of success with this wanna-be tweak are no more reliable than the average Bigfoot sighting. That is, people see what they want to see.
End of story. Unless of course you believe there was a second shooter in Dealey Plaza.