DEP on XP (Pro)

Not sure if it's the same on Home.

I've always just used the default "for essential Windows programs and services only". But I just decided to switch it up and turn it on for all programs and services except those I select.

I really wish it was a whitelist instead of a blacklist, because I ended up blacklisting almost every program on my computer. Fortunately, I don't have much on my box. I only spared a few internet facing things (i.e. Firefox, Pidgin, Sandboxie, Comodo). As is the general logic. So pretty poor implementation of this feature I'd say.

I noticed that after changing this, at boot my physical memory usage is now even lighter than before. I wonder why this is the case? I expected the opposite to be true, if any change at all.

Also it didn't save my list the first time. It asked for a reboot, I did so, and the list was gone. But apparently the second time is a charm, and it stuck.

And yes, I know DEP by itself isn't nearly as strong as when combined with other mitigation techniques. And no, I'm not using EMET. I did in the past and noticed a definitive slowdown. I notice it from installing .NET Framework alone for that matter (needed for EMET).

Anyone else notice lower RAM usage after turning DEP on for all programs/services on XP? Or any other stories/experiences you'd like to share with me? Advice welcome too (other than the EMET thing).