diff --git a/src/Cones/epitrrelentropytri.jl b/src/Cones/epitrrelentropytri.jl
index 0e097cf24..18817cb12 100644
--- a/src/Cones/epitrrelentropytri.jl
+++ b/src/Cones/epitrrelentropytri.jl
@@ -69,6 +69,16 @@ mutable struct EpiTrRelEntropyTri{T <: Real, R <: RealOrComplex{T}} <: Cone{T}
     mat3::Matrix{R}
     mat4::Matrix{R}
     Wsim_Δ3::Array{R, 3}
+    V_dir_sim::Matrix{R}
+    W_dir_sim::Matrix{R}
+    VW_dir_sim::Matrix{R}
+    diff_dot_V_VV::Matrix{R}
+    diff_dot_V_VW::Matrix{R}
+    diff_dot_W_WW::Matrix{R}
+    Vvd::Vector{T}
+    Wwd::Vector{T}
+    VWwd::Vector{T}
+    VWvd::Vector{T}
 
     function EpiTrRelEntropyTri{T, R}(
         dim::Int;
@@ -130,6 +140,16 @@ function setup_extra_data!(
     cone.mat3 = zeros(R, d, d)
     cone.mat4 = zeros(R, d, d)
     cone.Wsim_Δ3 = zeros(R, d, d, d)
+    cone.V_dir_sim = zeros(R, d, d)
+    cone.W_dir_sim = zeros(R, d, d)
+    cone.VW_dir_sim = zeros(R, d, d)
+    cone.diff_dot_V_VV = zeros(R, d, d)
+    cone.diff_dot_V_VW = zeros(R, d, d)
+    cone.diff_dot_W_WW = zeros(R, d, d)
+    cone.Vvd = zeros(T, vw_dim)
+    cone.Wwd = zeros(T, vw_dim)
+    cone.VWwd = zeros(T, vw_dim)
+    cone.VWvd = zeros(T, vw_dim)
     return
 end
 
@@ -206,8 +226,11 @@ function update_grad(
     mat3 = cone.mat3
     g = cone.grad
 
-    spectral_outer!(Vi, V_vecs, inv.(V_λ), cone.mat)
-    spectral_outer!(Wi, W_vecs, inv.(W_λ), cone.mat)
+    @views tempvec = cone.tempvec[1:(cone.d)]
+    @. tempvec = inv(V_λ)
+    spectral_outer!(Vi, V_vecs, tempvec, cone.mat)
+    @. tempvec = inv(W_λ)
+    spectral_outer!(Wi, W_vecs, tempvec, cone.mat)
 
     g[1] = -zi
 
@@ -371,6 +394,7 @@ function dder3(
     dir::AbstractVector{T},
 ) where {T <: Real, R <: RealOrComplex{T}}
     cone.dder3_aux_updated || update_dder3_aux(cone)
+    dder3 = cone.dder3
     rt2 = cone.rt2
     V_idxs = cone.V_idxs
     W_idxs = cone.W_idxs
@@ -383,57 +407,57 @@ function dder3(
     dzdW = cone.dzdW
     mat = cone.mat
     mat2 = cone.mat2
-    dder3 = cone.dder3
+    V_dir_sim = cone.V_dir_sim
+    W_dir_sim = cone.W_dir_sim
+    VW_dir_sim = cone.VW_dir_sim
+    diff_dot_V_VV = cone.diff_dot_V_VV
+    diff_dot_V_VW = cone.diff_dot_V_VW
+    diff_dot_W_WW = cone.diff_dot_W_WW
+
+    Vvd = cone.Vvd
+    Wwd = cone.Wwd
+    VWwd = cone.VWwd
+    VWvd = cone.VWvd
 
     u_dir = dir[1]
     @views v_dir = dir[V_idxs]
     @views w_dir = dir[W_idxs]
 
     # v, w
-    # TODO prealloc
-    V_dir = Hermitian(zero(mat), :U)
-    W_dir = Hermitian(zero(mat), :U)
-    V_dir_sim = zero(mat)
-    W_dir_sim = zero(mat)
-    VW_dir_sim = zero(mat)
-    W_part_1 = zero(mat)
-    V_part_1 = zero(mat)
-    d3WlogVdV = zero(mat)
-    diff_dot_V_VV = zero(mat)
-    diff_dot_V_VW = zero(mat)
-    diff_dot_W_WW = zero(mat)
-
-    svec_to_smat!(V_dir.data, v_dir, rt2)
-    svec_to_smat!(W_dir.data, w_dir, rt2)
-    spectral_outer!(V_dir_sim, V_vecs', V_dir, mat)
-    spectral_outer!(W_dir_sim, W_vecs', W_dir, mat)
-    spectral_outer!(VW_dir_sim, V_vecs', W_dir, mat)
+    V_dir = svec_to_smat!(mat, v_dir, rt2)
+    spectral_outer!(V_dir_sim, V_vecs', Hermitian(V_dir, :U), mat2)
+
+    W_dir = svec_to_smat!(mat, w_dir, rt2)
+    spectral_outer!(W_dir_sim, W_vecs', Hermitian(W_dir, :U), mat2)
+    spectral_outer!(VW_dir_sim, V_vecs', Hermitian(W_dir, :U), mat2)
 
     for k in 1:(cone.d)
         @views mul!(mat2[:, k], cone.Wsim_Δ3[:, :, k], V_dir_sim[:, k])
     end
+
     @. mat = mat2 + mat2'
     spectral_outer!(mat, V_vecs, Hermitian(mat, :U), mat2)
-    Vvd = smat_to_svec!(zero(w_dir), mat, rt2)
+    smat_to_svec!(Vvd, mat, rt2)
 
     @. mat = W_dir_sim * cone.Δ2_W
     spectral_outer!(mat, W_vecs, Hermitian(mat, :U), mat2)
-    Wwd = smat_to_svec!(zero(w_dir), mat, rt2)
+    smat_to_svec!(Wwd, mat, rt2)
 
     @. mat = VW_dir_sim * cone.Δ2_V
     spectral_outer!(mat, V_vecs, Hermitian(mat, :U), mat2)
-    VWwd = smat_to_svec!(zero(w_dir), mat, rt2)
+    smat_to_svec!(VWwd, mat, rt2)
 
     @. mat = V_dir_sim * cone.Δ2_V
     spectral_outer!(mat, V_vecs, Hermitian(mat, :U), mat2)
-    VWvd = smat_to_svec!(zero(w_dir), mat, rt2)
+    smat_to_svec!(VWvd, mat, rt2)
 
     const0 = zi * u_dir + dot(v_dir, dzdV) + dot(w_dir, dzdW)
     const1 =
         abs2(const0) + zi * (-dot(v_dir, VWwd) + (-dot(v_dir, Vvd) + dot(w_dir, Wwd)) / 2)
 
-    V_part_1a = -const0 * (Vvd + VWwd)
-    W_part_1a = Wwd - VWvd
+    Vvd .+= VWwd
+    V_part_1a = Vvd .*= -const0
+    W_part_1a = Wwd .-= VWvd
 
     # u
     dder3[1] = zi * const1
@@ -457,9 +481,11 @@ function dder3(
     end
 
     # v
-    d3WlogVdV!(d3WlogVdV, Δ3_V, V_λ, V_dir_sim, cone.W_sim, mat)
-    svec_to_smat!(V_part_1, V_part_1a, rt2)
-    @. V_dir_sim /= sqrt(V_λ)'
+    d3WlogVdV = d3WlogVdV!(mat2, Δ3_V, V_λ, V_dir_sim, cone.W_sim, mat)
+    V_part_1 = svec_to_smat!(cone.mat3, V_part_1a, rt2)
+    @views tempvec = cone.tempvec[1:(cone.d)]
+    tempvec .= sqrt.(V_λ)
+    @. V_dir_sim /= tempvec'
     ldiv!(Diagonal(V_λ), V_dir_sim)
     V_part_2 = d3WlogVdV
     @. V_part_2 += diff_dot_V_VW + diff_dot_V_VW'
@@ -471,10 +497,12 @@ function dder3(
     @. dder3_V += const1 * dzdV
 
     # w
-    svec_to_smat!(W_part_1, W_part_1a, rt2)
+    W_part_1 = svec_to_smat!(V_part_1, W_part_1a, rt2)
     spectral_outer!(mat2, V_vecs, Hermitian(diff_dot_V_VV, :U), mat)
     axpby!(true, mat2, const0, W_part_1)
-    @. W_dir_sim /= sqrt(W_λ)'
+    @views tempvec = cone.tempvec[1:(cone.d)]
+    tempvec .= sqrt.(W_λ)
+    @. W_dir_sim /= tempvec'
     ldiv!(Diagonal(W_λ), W_dir_sim)
     W_part_2 = diff_dot_W_WW
     mul!(W_part_2, W_dir_sim, W_dir_sim', true, -zi)