ImmediatelyFast 1.16.4 released on 27 August 2026 with a new optimisation and a specific claim attached to it: batching animated GUI item atlas clears, worth roughly 15 percent when several different animated or enchanted items are on screen at once.
What that means in plain terms
Enchanted items have a moving glint. Animated items – clocks, compasses, some modded blocks – have moving textures. Every one of those requires the game to update part of a texture atlas, and until now each did it separately.
Batching those updates means doing the work once for many items rather than once per item. The saving scales with how many such items are visible.
Where 15 percent actually applies
An inventory screen full of enchanted gear. A chest of shulker boxes with enchanted contents. A creative inventory. Not while you are walking around outside, where the number of animated items on screen is usually zero.
This is the honest reading of most performance claims: real, measured, and conditional on a specific situation. The mod’s author states the condition, which is more than most do.
The storage angle
Anyone with a well-organised base is opening a lot of inventory screens, and anyone with a shulker-based system is opening screens full of items with glints on them. This optimisation lands squarely on that use case.
Whether your base is organised well enough for that to matter is a separate problem, and organising without opening every box is the part most people skip.
What ImmediatelyFast is generally
A collection of rendering optimisations for things the game draws immediately rather than in batches – GUI elements, text, item models, particles. It is unglamorous and it is one of the most reliably beneficial mods available, precisely because the inefficiencies it targets are everywhere.
It fits into the standard stack without conflict, and the five-mod shortlist explains which symptom each member addresses so you are not installing all of them blind.
Release notes in full
- New optimisation: batch animated GUI item atlas clears, about 15 percent improvement in the relevant case.
- Fixed a config file handle leak.
- Fixed a config key typo in the runtime config API.
Follow-up
1.6.14 on 13 September 2026 fixed rendering issues introduced in 1.6.13 on the 1.21 line, along with REI recipe tooltip rendering. If you updated in early September and saw tooltip artefacts, that was it.
Measuring it yourself
Open a double chest of enchanted gear and watch the frame rate with the mod on and off. It is one of the few optimisation claims you can verify in thirty seconds.
What “immediate mode” means
The mod’s name refers to immediate-mode rendering: drawing things one at a time as they come up, rather than collecting them and drawing them together. It is simple, it is what Minecraft does for GUI elements, and it is slow when there are many small things.
Batching them – collecting the draws and issuing fewer, larger commands – is the whole idea behind the mod, applied in place after place.
Where GUI rendering costs real frames
- Inventory and chest screens, especially with enchanted items.
- The creative inventory, which draws hundreds of item models.
- Recipe viewers, which are a grid of item models updating live.
- Large HUDs from modpacks – minimaps, waypoint lists, status bars.
Modded HUDs are the underrated one. A pack with five HUD mods can spend a meaningful slice of every frame on things drawn at the edge of the screen.
The config file handle leak
A file handle leak means the mod opened files and did not close them. Left alone long enough, a process runs out of handles and things start failing in unrelated places.
It is the kind of bug that never appears in a short test and shows up in someone’s eight-hour session as an inexplicable error.
Measuring rendering versus logic
Open the debug screen and compare frame rate standing still in an empty area against the same spot with your inventory open. A large drop with the inventory open points at GUI rendering, which is what this mod addresses.
If both numbers are equally bad, the problem is elsewhere and this mod will not help.
Release line
- 1.16.4, 27 August 2026 – GUI atlas batching, for 26.2.
- 1.6.13, early September – introduced a rendering regression on the 1.21 line.
- 1.6.14, 13 September 2026 – fixed that regression and REI tooltip rendering.
The parallel numbering between version lines is confusing and is worth double-checking before downloading.
Worth ending on the honesty of the claim itself. A stated 15 percent improvement, with the exact condition it applies under, is more useful than a mod page promising better performance generally. It tells you whether the mod addresses your problem before you install it, which is what every performance claim should do and almost none do. Judge optimisation mods by how precisely they describe their own benefit.
Images: ShulkerBoxTooltip and MoreCulling project galleries on Modrinth.