Sims 3 Performance Patch

Hi! Since this mod made waves on Tumblr, here it is now on the Nexus. EA App is now supported along with Steam and retail/disc versions of the game. Source code also included, so you can poke at it, strip it down further, make your own franken-ASI with other mods, or whatever you please. Just keep it open and credit pls.

What it does:

Loading speed

Script type index (MonoTypeEHashProbe): the game's script engine looks up "what type is this object?" millions of times while a save loads, using a slow internal table. This patch builds a smarter index for that table and keeps it up to date. It is the single biggest win in this mod and where most of the 18-min-to-4-min load time improvement comes from. SimulatorStageProfiler is a small helper this index relies on, leave both on or both off.

Package index warm-up (PackageIndexWarmup): while you're still at the main menu, a background task pre-reads the table-of-contents of your Mods packages into Windows' file cache, so the game doesn't wait on the disk for them later. Costs nothing visible, helps most on hard drives.

Short-wait tuning (ShortWaitSpin): when game threads hand work to each other they often wait "just a moment". Windows turns that into a much longer sleep than intended. This makes very short waits snappier.

Memory headroom (Error 12, out-of-memory crashes)

The Sims 3 has 4 GB of address space no matter how much RAM you have.

What you see in Task Manager is not that. The gap between how much RAM your game is using vs how much virtual address space (VAS) it allocates can be several hundred megabytes. That is why your game might crash even if it doesn't look like it should in Task Manager. Once VAS reaches 4GB, it's game over. When that runs out you get Error 12 on saving or crashes. These three patches reclaim address space:

STBL Text-table slimming (StblBucketLayoutTuning): the game reserves a wildly oversized memory layout for every localized-text table it loads (10,000+ of them in a big save). This patch right-sizes that layout. Measured saving: about 290 MB, the text itself byte-identical.

Thread stack diet (ThreadStackDiet): the game creates ~150 worker threads and Windows reserves 1 MB of address space for each, though they use a fraction of it. Now threads get a 0. 5 MB reservation instead: ~70 MB back.

Arena growth tuning (AllocatorArenaTuning): the game's internal memory arenas grow in big 16 MB steps; this changes them to grow in smaller steps so less space sits reserved but unused. The game might still reserve more of the smaller arenas, though.

Smoothness

Text lookup cache (LocalizedStringCache): every tooltip, moodlet and UI label triggers a search through all those text tables. This caches the answers. If you ever see a wrong or blank text label, turn this off and please report it.

Type-check cache (MonoIsinstCache): scripts constantly ask "is this object a kind of X?". The answers never change, so this remembers them.

Installation instructions

Copy `Sims3Performance.asi` and `Sims3Performance.ini` into `...\The Sims 3\Game\Bin` (the folder with `TS3W.exe` or `TS3.exe` ).

If you want to uninstall, just delete the files.

Requirements

Requires wininet.dll 32bit (from Ultimate ASI Loader or elsewhere).

Shout outs

Sims3fiend for the Sims 3 Settings Setter. The bones of this mod were partly born from it.

Sims 3 Creators Cave Discord server members for testing.

riperviwe for help with EA app compat.