diff --git a/Cargo.lock b/Cargo.lock
index 79217f7e2..5883b9484 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -256,7 +256,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "crunchy"
-version = "0.1.1"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -365,7 +365,7 @@ dependencies = [
 name = "ethash"
 version = "1.7.0"
 dependencies = [
- "crunchy 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crunchy 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "primal 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2949,7 +2949,7 @@ dependencies = [
 "checksum core-foundation 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "20a6d0448d3a99d977ae4a2aa5a98d886a923e863e81ad9ff814645b6feb3bbd"
 "checksum core-foundation-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "05eed248dc504a5391c63794fe4fb64f46f071280afaa1b73308f3c0ce4574c5"
 "checksum crossbeam 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)" = "0c5ea215664ca264da8a9d9c3be80d2eaf30923c259d03e870388eb927508f97"
-"checksum crunchy 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "803315676d3fc09db67636977586262e7d1a6c5bdb291810efd5ceb48a0d5d58"
+"checksum crunchy 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e6aa9cb5f2d7bffc4eecfaf924fe450549dc4f0c3a6502298dc24f968b1eabbe"
 "checksum crypt32-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e34988f7e069e0b2f3bfc064295161e489b2d4e04a2e4248fb94360cdf00b4ec"
 "checksum ctrlc 1.1.1 (git+https://github.com/paritytech/rust-ctrlc.git)" = "<none>"
 "checksum daemonize 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "271ec51b7e0bee92f0d04601422c73eb76ececf197026711c97ad25038a010cf"
diff --git a/ethash/src/compute.rs b/ethash/src/compute.rs
index 0db5200dc..2fcaeb58f 100644
--- a/ethash/src/compute.rs
+++ b/ethash/src/compute.rs
@@ -360,12 +360,19 @@ fn calculate_dag_item(node_index: u32, cache: &[Node]) -> Node {
 		*ret.as_words_mut().get_unchecked_mut(0) ^= node_index;
 		sha3::sha3_512(ret.bytes.as_mut_ptr(), ret.bytes.len(), ret.bytes.as_ptr(), ret.bytes.len());
 
-		for i_usize in 0..ETHASH_DATASET_PARENTS {
-			let i = i_usize as u32;
+		debug_assert_eq!(NODE_WORDS, 16);
+		for i in 0..ETHASH_DATASET_PARENTS as u32 {
 			let parent_index = fnv_hash(node_index ^ i, *ret.as_words().get_unchecked(i as usize % NODE_WORDS)) % num_parent_nodes as u32;
 			let parent = cache.get_unchecked(parent_index as usize);
-			for w in 0..NODE_WORDS {
-				*ret.as_words_mut().get_unchecked_mut(w) = fnv_hash(*ret.as_words().get_unchecked(w), *parent.as_words().get_unchecked(w));
+
+			unroll! {
+				for w in 0..16 {
+					*ret.as_words_mut().get_unchecked_mut(w) =
+						fnv_hash(
+							*ret.as_words().get_unchecked(w),
+							*parent.as_words().get_unchecked(w)
+						);
+				}
 			}
 		}
 
@@ -392,18 +399,20 @@ fn light_new(block_number: u64) -> Light {
 			sha3::sha3_512(nodes.get_unchecked_mut(i).bytes.as_mut_ptr(), NODE_BYTES, nodes.get_unchecked(i - 1).bytes.as_ptr(), NODE_BYTES);
 		}
 
+		debug_assert_eq!(NODE_WORDS, 16);
+
 		// This _should_ get unrolled by the compiler, since it's not using the loop variable.
 		for _ in 0..ETHASH_CACHE_ROUNDS {
 			for i in 0..num_nodes {
 				let idx = *nodes.get_unchecked_mut(i).as_words().get_unchecked(0) as usize % num_nodes;
 				let mut data = nodes.get_unchecked((num_nodes - 1 + i) % num_nodes).clone();
 
-				debug_assert_eq!(NODE_WORDS, 16);
 				unroll! {
 					for w in 0..16 {
 						*data.as_words_mut().get_unchecked_mut(w) ^= *nodes.get_unchecked(idx).as_words().get_unchecked(w);
 					}
 				}
+
 				sha3_512(&data.bytes, &mut nodes.get_unchecked_mut(i).bytes);
 			}
 		}