That is correct, IE doesn't change, the issue regarding IE is that if you have IE7 installed and want the ability to back rev it to IE6, you must uninstall IE7, apply the SP3 patch, and then reapply IE7. The SP3 install because it makes so many changes, removes the the ability to back rev any existing installed MS patches, not just IE.
I find it funny that the SP3 install is larger than the actual install files for XP!
The majority of SP3 issues are related to drivers and the HP-AMD issue because of the way HP desktops were loaded. The AMD HP laptops don't seem to have the issue as they were loaded from a different base install.
The AMD HP issue is because the image that is used has the registry entry for the Intel driver, but doesn't have the intel driver on the disk. SP3 checks the registry, sees the entry, and loads the intel driver. This causes the system to BSOD and reboot. This was discovered by someone else, you can see the 0x0000007E stop error if you press F8 and choose the option to not reboot on failure.
You may be able to get into safe mode and remove the intel driver registry entry which will prevent the driver from being loaded and allow the system to boot normally.
Jesper Johansson\'s blog has all of the information and a small program to check if your system is susceptible to the issue, and then it fixes it by removing the registry entry.