diff --git a/src/arithmetic.rs b/src/arithmetic.rs
index 750c9fb1..a7193a87 100644
--- a/src/arithmetic.rs
+++ b/src/arithmetic.rs
@@ -182,7 +182,6 @@ fn multiexp_serial<C: CurveAffine>(coeffs: &[C::Scalar], bases: &[C], acc: &mut
 
 /// Performs a small multi-exponentiation operation.
 /// Uses the double-and-add algorithm with doublings shared across points.
-
 pub fn small_multiexp<C: CurveAffine>(coeffs: &[C::Scalar], bases: &[C]) -> C::Projective {
     let coeffs: Vec<[u8; 32]> = coeffs.iter().map(|a| a.to_bytes()).collect();
     let mut acc = C::Projective::zero();
@@ -195,8 +194,8 @@ pub fn small_multiexp<C: CurveAffine>(coeffs: &[C::Scalar], bases: &[C]) -> C::P
             // for each coeff
             for coeff_idx in 0..coeffs.len() {
                 let byte = coeffs[coeff_idx][byte_idx];
-                if (byte >> bit_idx & 1) != 0 {
-                    acc = acc + &bases[coeff_idx].to_projective();
+                if ((byte >> bit_idx) & 1) != 0 {
+                    acc += bases[coeff_idx];
                 }
             }
         }
diff --git a/src/poly/commitment/prover.rs b/src/poly/commitment/prover.rs
index 0349b28f..c66fe827 100644
--- a/src/poly/commitment/prover.rs
+++ b/src/poly/commitment/prover.rs
@@ -1,8 +1,8 @@
 use super::super::{Coeff, Polynomial};
 use super::{Blind, OpeningProof, Params};
 use crate::arithmetic::{
-    best_multiexp, compute_inner_product, get_challenge_scalar, small_multiexp, Challenge, Curve,
-    CurveAffine, Field,
+    best_multiexp, compute_inner_product, get_challenge_scalar, parallelize, small_multiexp,
+    Challenge, Curve, CurveAffine, Field,
 };
 use crate::transcript::Hasher;
 
@@ -220,11 +220,14 @@ fn parallel_generator_collapse<C: CurveAffine>(
     challenge_inv: C::Scalar,
 ) {
     let len = g.len() / 2;
-    let (g_lo, g_hi) = g.split_at_mut(len);
+    let (mut g_lo, g_hi) = g.split_at_mut(len);
 
-    let mut tmp = Vec::with_capacity(g_lo.len());
-    for (g_lo, g_hi) in g_lo.iter().zip(g_hi.iter()) {
-        tmp.push(small_multiexp(&[challenge_inv, challenge], &[*g_lo, *g_hi]));
-    }
-    C::Projective::batch_to_affine(&tmp, g_lo);
+    parallelize(&mut g_lo, |g_lo, start| {
+        let g_hi = &g_hi[start..];
+        let mut tmp = Vec::with_capacity(g_lo.len());
+        for (g_lo, g_hi) in g_lo.iter().zip(g_hi.iter()) {
+            tmp.push(small_multiexp(&[challenge_inv, challenge], &[*g_lo, *g_hi]));
+        }
+        C::Projective::batch_to_affine(&tmp, g_lo);
+    });
 }