Wads that have taxed average pc in the last 10-15 years?

[invictius]

Back in the 90's readmes would say you need a fast 486 or pentium to run a certain wad but I can't think of anything over 15 years old that needed anything above what the average gamer had, apart from frozen time (which would run properly in prboom anyway). I think someone gave the example of phobos anomaly reborn on a 2001 system but that was made in 2006.

[Rachael]

Stronghold and Paranoid are both approximately that age and made PC's of their time work very hard.

[Graf Zahl]

P:AR was released in 2001 as a 3 level teaser and in 2003 as a full episode. 2006 may have been a point release for bugfixing.
Back in the early years the crane in M3 certainly made some computers choke, the first time I was able to see that map with 60+ fps was with the computer I bought in 2007.
KDiZD is also a map set that taxed the systems of the time it was made in.

[FFFFRRRR]

I feel like Sunder belongs on this list. Not for all maps, but some are certainly very heavy on performance. Map 9, 10, 11, 12 and 14 I believe.
I think its the mix of seeing a lot of sectors at the same time and a lot of monsters being active. Possibly, that is entirely intentional by the author.

Russian Overkills Superweapons might make some PCs stutter, too.