diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/storage/StorageBusBlockEntity.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/storage/StorageBusBlockEntity.kt
index e3c76b269..711a617e4 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/storage/StorageBusBlockEntity.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/storage/StorageBusBlockEntity.kt
@@ -46,6 +46,7 @@ import kotlin.collections.HashMap
 
 private class SlotTuple(val slot: Int, val stack: ItemStack)
 private class TrackedTuple(override val stack: ItemStackWrapper, override val id: UUID) : IStorageTuple<ItemStackWrapper> {
+	// do not use hash map because we need keys to be iterated in natural order
 	val children = Int2ObjectAVLTreeMap<SlotTuple>()
 
 	override fun toString(): String {
diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/AndroidStationScreen.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/AndroidStationScreen.kt
index 7b6f5853e..8826ac809 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/AndroidStationScreen.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/AndroidStationScreen.kt
@@ -6,6 +6,7 @@ import com.mojang.blaze3d.vertex.PoseStack
 import it.unimi.dsi.fastutil.ints.Int2FloatAVLTreeMap
 import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap
 import it.unimi.dsi.fastutil.ints.Int2ObjectFunction
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap
 import net.minecraft.ChatFormatting
 import net.minecraft.client.Minecraft
 import net.minecraft.network.chat.Component
@@ -524,7 +525,7 @@ class AndroidStationScreen constructor(p_97741_: AndroidStationMenu, p_97742_: I
 	MatteryScreen<AndroidStationMenu>(p_97741_, p_97742_, p_97743_) {
 
 	private fun makeCanvas(isPreview: Boolean): DraggableCanvasPanel<AndroidStationScreen> {
-		val rows = Int2ObjectAVLTreeMap<EditablePanel<AndroidStationScreen>>()
+		val rows = Int2ObjectOpenHashMap<EditablePanel<AndroidStationScreen>>()
 
 		val canvas = object : DraggableCanvasPanel<AndroidStationScreen>(this@AndroidStationScreen, null) {
 			private val random = Random()
diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/MatteryScreen.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/MatteryScreen.kt
index b2e6876cb..01a6a3f8c 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/MatteryScreen.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/client/screen/MatteryScreen.kt
@@ -4,6 +4,7 @@ import com.mojang.blaze3d.systems.RenderSystem
 import com.mojang.blaze3d.vertex.PoseStack
 import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap
 import it.unimi.dsi.fastutil.ints.Int2ObjectFunction
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap
 import net.minecraft.ChatFormatting
 import net.minecraft.client.gui.Font
 import net.minecraft.client.gui.screens.inventory.AbstractContainerScreen
@@ -63,7 +64,7 @@ abstract class MatteryScreen<T : MatteryMenu>(menu: T, inventory: Inventory, tit
 		}
 	}
 
-	private val inventorySlotsRows = Int2ObjectAVLTreeMap<EditablePanel<MatteryScreen<*>>>()
+	private val inventorySlotsRows = Int2ObjectOpenHashMap<EditablePanel<MatteryScreen<*>>>()
 	private lateinit var slotListCanvas: EditablePanel<MatteryScreen<*>>
 	private lateinit var inventoryScrollbar: DiscreteScrollBarPanel<MatteryScreen<*>>
 
diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/compat/ExtendedInventoryHandler.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/compat/ExtendedInventoryHandler.kt
index c2d865db0..2e1a2afdc 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/compat/ExtendedInventoryHandler.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/compat/ExtendedInventoryHandler.kt
@@ -3,6 +3,7 @@ package ru.dbotthepony.mc.otm.compat
 import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap
 import it.unimi.dsi.fastutil.ints.Int2ObjectArrayMap
 import it.unimi.dsi.fastutil.ints.Int2ObjectFunction
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap
 import it.unimi.dsi.fastutil.objects.ReferenceArraySet
 import net.minecraft.network.FriendlyByteBuf
 import net.minecraft.world.SimpleContainer
@@ -37,7 +38,7 @@ private class MenuConfiguration(
 	}
 
 	private val slotPositions = Int2ObjectArrayMap<List<SlotPos>>()
-	private val rows = Int2ObjectAVLTreeMap<List<Slot>>()
+	private val rows = Int2ObjectOpenHashMap<List<Slot>>()
 	val isIncomplete: Boolean
 
 	private fun getRow(index: Int, matteryPlayer: MatteryPlayerCapability) = rows.computeIfAbsent(index, Int2ObjectFunction {
@@ -200,6 +201,7 @@ class InventoryScrollPacket(val scroll: Int) : MatteryPacket {
 		}
 
 		menuConfigurations.computeIfAbsent(containerMenu) {
+			// do not use hash map because we need keys be iterated in natural order
 			val originalSlots = Int2ObjectAVLTreeMap<Slot>()
 
 			for (slot in it.slots) {
diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/menu/data/NetworkedItemView.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/menu/data/NetworkedItemView.kt
index 17522dfd7..251540c89 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/menu/data/NetworkedItemView.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/menu/data/NetworkedItemView.kt
@@ -2,6 +2,7 @@ package ru.dbotthepony.mc.otm.menu.data
 
 import com.mojang.blaze3d.platform.InputConstants
 import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap
 import net.minecraft.client.Minecraft
 import net.minecraft.client.gui.screens.Screen
 import net.minecraft.network.FriendlyByteBuf
@@ -205,7 +206,7 @@ open class NetworkedItemView(val ply: Player, val menu: MatteryMenu, val remote:
 		get() = ITEM_STORAGE
 
 	// this (how client see and interact with)
-	val localState = Int2ObjectAVLTreeMap<NetworkedItem>()
+	val localState = Int2ObjectOpenHashMap<NetworkedItem>()
 
 	val sortedView = LinkedList<NetworkedItem>()
 	var sorter: Comparator<ItemStack> = NAME_SORTER
diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt
index 7043a50d4..a62f5e1a8 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/network/FieldSynchronizer.kt
@@ -1,6 +1,8 @@
 package ru.dbotthepony.mc.otm.network
 
 import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap
+import it.unimi.dsi.fastutil.ints.Int2ObjectArrayMap
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap
 import it.unimi.dsi.fastutil.io.FastByteArrayInputStream
 import it.unimi.dsi.fastutil.io.FastByteArrayOutputStream
 import it.unimi.dsi.fastutil.objects.ObjectArraySet
@@ -1064,9 +1066,9 @@ class FieldSynchronizer(private val callback: Runnable, private val alwaysCallCa
 		return values
 	}
 
-	private val idToField = Int2ObjectAVLTreeMap<IField<*>>()
+	private val idToField = Int2ObjectOpenHashMap<IField<*>>()
 	private val missingFields = ObjectArraySet<String>()
-	private val missingFieldsMap = Int2ObjectAVLTreeMap<String>()
+	private val missingFieldsMap = Int2ObjectArrayMap<String>()
 
 	fun applyNetworkPayload(stream: InputStream): Int {
 		if (stream.read() > 0) {