diff --git a/.github/workflows/perf.yml b/.github/workflows/perf.yml
index 6112c761..e678aebf 100644
--- a/.github/workflows/perf.yml
+++ b/.github/workflows/perf.yml
@@ -16,6 +16,7 @@ jobs:
       MOC_VERSION: 0.10.4
       IC_WASM_VERSION: 0.7.0
       RUSTC_VERSION: 1.75.0
+      MOC_ARTIFACT: 1242507845
     steps:
       - uses: actions/checkout@v3
       - name: Checkout out gh-pages report
@@ -64,9 +65,10 @@ jobs:
           chmod a+x /usr/local/bin/ic-repl
           npm i -g ic-mops
           dfx cache install
-          cd $(dfx cache show)
-          wget https://github.com/dfinity/motoko/releases/download/$MOC_VERSION/motoko-Darwin-x86_64-$MOC_VERSION.tar.gz
-          tar zxvf motoko-Darwin-x86_64-$MOC_VERSION.tar.gz
+          wget https://nightly.link/dfinity/motoko/actions/artifacts/$MOC_ARTIFACT.zip
+          unzip $MOC_ARTIFACT.zip
+          chmod a+x bin/moc
+          cp -rf bin/moc $(dfx cache show)
           wget https://github.com/dfinity/ic-wasm/releases/download/$IC_WASM_VERSION/ic-wasm-macos
           cp ./ic-wasm-macos /usr/local/bin/ic-wasm
           chmod a+x /usr/local/bin/ic-wasm
diff --git a/collections/motoko/src/ZhenyaHashmap.mo b/collections/motoko/src/ZhenyaHashmap.mo
index 7d2d20e9..55205f9d 100644
--- a/collections/motoko/src/ZhenyaHashmap.mo
+++ b/collections/motoko/src/ZhenyaHashmap.mo
@@ -5,12 +5,18 @@ import Iter "mo:base/Iter";
 import Option "mo:base/Option";
 import Random "random";
 import Profiling "../../../utils/motoko/Profiling";
-
+import Prim "mo:prim";
 actor {
     stable let profiling = Profiling.init();
-    
-    func f_hash(x : Nat64) : Nat32 = Hash.hash(Nat64.toNat x);
-    let hash : HashMap.HashUtils<Nat64> = (f_hash, Nat64.equal);
+
+
+    // avoid boxed hashes
+    func hashNat64(key: Nat64) : Nat32 {
+      Prim.nat64ToNat32(key & 0x7ff_ffff); // Nat32 is 27-bit
+    };
+
+    let hash : HashMap.HashUtils<Nat64> = (hashNat64, func (x,y) = x == y);
+
     stable var map = HashMap.new<Nat64, Nat64>();
     let rand = Random.new(null, 42);
 
diff --git a/collections/motoko/src/hashmap.mo b/collections/motoko/src/hashmap.mo
index 92b70983..ea8f1b3e 100644
--- a/collections/motoko/src/hashmap.mo
+++ b/collections/motoko/src/hashmap.mo
@@ -9,7 +9,6 @@ import Profiling "../../../utils/motoko/Profiling";
 
 actor {
     stable let profiling = Profiling.init();
-    
     func hash(x: Nat64) : Nat32 = Hash.hash(Nat64.toNat x);
     var map = HashMap.HashMap<Nat64, Nat64>(0, Nat64.equal, hash);
     stable var stableMap: [(Nat64, Nat64)] = [];
diff --git a/collections/motoko/src/random.mo b/collections/motoko/src/random.mo
index 4a4222fb..2b67db8c 100644
--- a/collections/motoko/src/random.mo
+++ b/collections/motoko/src/random.mo
@@ -19,7 +19,7 @@ module {
                };
           };
           state := state * 48271 % modulus;
-          ?state;
+          ?(state >> 4);
       };
     };
     public func get_memory(): (Nat,Nat,Nat) {