diff --git a/engine-tests/src/tests/uniswap.rs b/engine-tests/src/tests/uniswap.rs
index 49fdb41f2..21b7dfc28 100644
--- a/engine-tests/src/tests/uniswap.rs
+++ b/engine-tests/src/tests/uniswap.rs
@@ -57,7 +57,7 @@ fn test_uniswap_exact_output() {
     test_utils::assert_gas_bound(profile.all_gas(), 58);
     let wasm_fraction = 100 * profile.wasm_gas() / profile.all_gas();
     assert!(
-        20 <= wasm_fraction && wasm_fraction <= 30,
+        25 <= wasm_fraction && wasm_fraction <= 35,
         "{}% is not between 20% and 30%",
         wasm_fraction
     );
diff --git a/engine/src/engine.rs b/engine/src/engine.rs
index 2d1a9181f..b0c630b7e 100644
--- a/engine/src/engine.rs
+++ b/engine/src/engine.rs
@@ -408,6 +408,7 @@ pub struct Engine<'env, I: IO, E: Env> {
     env: &'env E,
     generation_cache: RefCell<BTreeMap<Address, u32>>,
     account_info_cache: RefCell<DupCache<Address, Basic>>,
+    contract_code_cache: RefCell<DupCache<Address, Vec<u8>>>,
     contract_storage_cache: RefCell<PairDupCache<Address, H256, H256>>,
 }
 
@@ -442,6 +443,7 @@ impl<'env, I: IO + Copy, E: Env> Engine<'env, I, E> {
             env,
             generation_cache: RefCell::new(BTreeMap::new()),
             account_info_cache: RefCell::new(DupCache::default()),
+            contract_code_cache: RefCell::new(DupCache::default()),
             contract_storage_cache: RefCell::new(PairDupCache::default()),
         }
     }
@@ -1420,7 +1422,18 @@ impl<'env, I: IO + Copy, E: Env> evm::backend::Backend for Engine<'env, I, E> {
 
     /// Checks if an address exists.
     fn exists(&self, address: H160) -> bool {
-        !is_account_empty(&self.io, &Address::new(address))
+        let address = Address::new(address);
+        let mut cache = self.account_info_cache.borrow_mut();
+        let basic_info = cache.get_or_insert_with(&address, || Basic {
+            nonce: get_nonce(&self.io, &address),
+            balance: get_balance(&self.io, &address).raw(),
+        });
+        if !basic_info.balance.is_zero() || !basic_info.nonce.is_zero() {
+            return false;
+        }
+        let mut cache = self.contract_code_cache.borrow_mut();
+        let code = cache.get_or_insert_with(&address, || get_code(&self.io, &address));
+        !code.is_empty()
     }
 
     /// Returns basic account information.
@@ -1439,7 +1452,11 @@ impl<'env, I: IO + Copy, E: Env> evm::backend::Backend for Engine<'env, I, E> {
 
     /// Returns the code of the contract from an address.
     fn code(&self, address: H160) -> Vec<u8> {
-        get_code(&self.io, &Address::new(address))
+        let address = Address::new(address);
+        self.contract_code_cache
+            .borrow_mut()
+            .get_or_insert_with(&address, || get_code(&self.io, &address))
+            .clone()
     }
 
     /// Get storage value of address at index.