Avast! antivirus let me choose whether to load its services before or after other system services.
I noticed that by unchecking that box (and letting avast load first) the system boot hangs and it is slower to load, while if I check it and let the system load its own services, the boot is smoother. The latter seems to be the best option, at least from the performance point of view, but I'm a bit concerned about security.
Now, being a feature included in the antivirus software, I prone to think that also from the security point of view there would be no problems to do so, but still, I wonder if loading Avast services after all other system ones could leave open a possible time-frame where I'm not protected against malware.