diff --git a/src/implementations/eigh.jl b/src/implementations/eigh.jl
index 40f2c557..19a190b1 100644
--- a/src/implementations/eigh.jl
+++ b/src/implementations/eigh.jl
@@ -43,7 +43,7 @@ function check_input(::typeof(eigh_full!), A::AbstractMatrix, DV, alg::DiagonalA
     @assert isdiag(A)
     m = size(A, 1)
     D, V = DV
-    @assert D isa Diagonal && V isa Diagonal
+    @assert D isa Diagonal
     @check_size(D, (m, m))
     @check_scalar(D, A, real)
     @check_size(V, (m, m))
@@ -79,7 +79,7 @@ function initialize_output(::Union{typeof(eigh_trunc!), typeof(eigh_trunc_no_err
 end
 
 function initialize_output(::typeof(eigh_full!), A::Diagonal, ::DiagonalAlgorithm)
-    return eltype(A) <: Real ? A : similar(A, real(eltype(A))), similar(A)
+    return eltype(A) <: Real ? A : similar(A, real(eltype(A))), similar(A, size(A)...)
 end
 function initialize_output(::typeof(eigh_vals!), A::Diagonal, ::DiagonalAlgorithm)
     return eltype(A) <: Real ? diagview(A) : similar(A, real(eltype(A)), size(A, 1))
@@ -146,15 +146,29 @@ end
 function eigh_full!(A::Diagonal, DV, alg::DiagonalAlgorithm)
     check_input(eigh_full!, A, DV, alg)
     D, V = DV
-    D === A || (diagview(D) .= real.(diagview(A)))
-    one!(V)
+    diagA = diagview(A)
+    I = sortperm(diagA; by = real)
+    if D === A
+        permute!(diagA, I)
+    else
+        diagview(D) .= real.(view(diagA, I))
+    end
+    zero!(V)
+    n = size(A, 1)
+    I .+= (0:(n - 1)) .* n
+    V[I] .= Ref(one(eltype(V)))
     return D, V
 end
 
 function eigh_vals!(A::Diagonal, D, alg::DiagonalAlgorithm)
     check_input(eigh_vals!, A, D, alg)
     Ad = diagview(A)
-    D === Ad || (D .= real.(Ad))
+    if D === Ad
+        sort!(Ad)
+    else
+        D .= real.(Ad)
+        sort!(D)
+    end
     return D
 end
 
diff --git a/src/implementations/truncation.jl b/src/implementations/truncation.jl
index 883c7759..be730bed 100644
--- a/src/implementations/truncation.jl
+++ b/src/implementations/truncation.jl
@@ -49,7 +49,7 @@ findtruncated(values::AbstractVector, ::NoTruncation) = Colon()
 
 function findtruncated(values::AbstractVector, strategy::TruncationByOrder)
     howmany = min(strategy.howmany, length(values))
-    return partialsortperm(values, 1:howmany; strategy.by, strategy.rev)
+    return sortperm(values; strategy.by, strategy.rev)[1:howmany]
 end
 function findtruncated_svd(values::AbstractVector, strategy::TruncationByOrder)
     strategy.by === abs || return findtruncated(values, strategy)
@@ -96,14 +96,8 @@ function _truncerr_impl(values::AbstractVector, I; atol::Real = 0, rtol::Real =
     # fast path to avoid checking all values
     ϵᵖ ≥ Nᵖ && return Base.OneTo(0)
 
-    truncerrᵖ = zero(real(eltype(values)))
-    rank = length(values)
-    for i in reverse(I)
-        truncerrᵖ += by(values[i])
-        truncerrᵖ ≥ ϵᵖ && break
-        rank -= 1
-    end
-
+    truncerrᵖ_array = cumsum(map(by, view(values, reverse(I))))
+    rank = length(values) - (findfirst(≥(ϵᵖ), truncerrᵖ_array) - 1)
     return Base.OneTo(rank)
 end
 
diff --git a/test/eig.jl b/test/eig.jl
index 7cc54c5d..df6fdf86 100644
--- a/test/eig.jl
+++ b/test/eig.jl
@@ -19,10 +19,10 @@ for T in (BLASFloats..., GenericFloats...)
     TestSuite.seed_rng!(123)
     if T ∈ BLASFloats
         if CUDA.functional()
-            TestSuite.test_eig(CuMatrix{T}, (m, m); test_trunc = false)
-            TestSuite.test_eig_algs(CuMatrix{T}, (m, m), (CUSOLVER_Simple(),); test_trunc = false)
-            TestSuite.test_eig(Diagonal{T, CuVector{T}}, m; test_trunc = false)
-            TestSuite.test_eig_algs(Diagonal{T, CuVector{T}}, m, (DiagonalAlgorithm(),); test_trunc = false)
+            TestSuite.test_eig(CuMatrix{T}, (m, m))
+            TestSuite.test_eig_algs(CuMatrix{T}, (m, m), (CUSOLVER_Simple(),))
+            TestSuite.test_eig(Diagonal{T, CuVector{T}}, m)
+            TestSuite.test_eig_algs(Diagonal{T, CuVector{T}}, m, (DiagonalAlgorithm(),))
         end
         #= not yet supported
         if AMDGPU.functional()
diff --git a/test/eigh.jl b/test/eigh.jl
index 8766ccc0..2efb4e15 100644
--- a/test/eigh.jl
+++ b/test/eigh.jl
@@ -22,10 +22,10 @@ for T in (BLASFloats..., GenericFloats...)
                 CUSOLVER_Jacobi(),
                 CUSOLVER_DivideAndConquer(),
             )
-            TestSuite.test_eigh(CuMatrix{T}, (m, m); test_trunc = false)
-            TestSuite.test_eigh_algs(CuMatrix{T}, (m, m), CUSOLVER_EIGH_ALGS; test_trunc = false)
-            TestSuite.test_eigh(Diagonal{T, CuVector{T}}, m; test_trunc = false)
-            TestSuite.test_eigh_algs(Diagonal{T, CuVector{T}}, m, (DiagonalAlgorithm(),); test_trunc = false)
+            TestSuite.test_eigh(CuMatrix{T}, (m, m))
+            TestSuite.test_eigh_algs(CuMatrix{T}, (m, m), CUSOLVER_EIGH_ALGS)
+            TestSuite.test_eigh(Diagonal{T, CuVector{T}}, m)
+            TestSuite.test_eigh_algs(Diagonal{T, CuVector{T}}, m, (DiagonalAlgorithm(),))
         end
         if AMDGPU.functional()
             ROCSOLVER_EIGH_ALGS = (
@@ -34,6 +34,7 @@ for T in (BLASFloats..., GenericFloats...)
                 ROCSOLVER_QRIteration(),
                 ROCSOLVER_Bisection(),
             )
+            # see https://github.com/JuliaGPU/AMDGPU.jl/issues/837
             TestSuite.test_eigh(ROCMatrix{T}, (m, m); test_trunc = false)
             TestSuite.test_eigh_algs(ROCMatrix{T}, (m, m), ROCSOLVER_EIGH_ALGS; test_trunc = false)
             TestSuite.test_eigh(Diagonal{T, ROCVector{T}}, m; test_trunc = false)
diff --git a/test/testsuite/eig.jl b/test/testsuite/eig.jl
index 2dbea8b9..61ed1fc8 100644
--- a/test/testsuite/eig.jl
+++ b/test/testsuite/eig.jl
@@ -3,19 +3,19 @@ using MatrixAlgebraKit: TruncatedAlgorithm
 using LinearAlgebra: I
 using GenericSchur
 
-function test_eig(T::Type, sz; test_trunc = true, kwargs...)
+function test_eig(T::Type, sz; kwargs...)
     summary_str = testargs_summary(T, sz)
     return @testset "eig $summary_str" begin
         test_eig_full(T, sz; kwargs...)
-        test_trunc && test_eig_trunc(T, sz; kwargs...)
+        test_eig_trunc(T, sz; kwargs...)
     end
 end
 
-function test_eig_algs(T::Type, sz, algs; test_trunc = true, kwargs...)
+function test_eig_algs(T::Type, sz, algs; kwargs...)
     summary_str = testargs_summary(T, sz)
     return @testset "eig algorithms $summary_str" begin
         test_eig_full_algs(T, sz, algs; kwargs...)
-        test_trunc && test_eig_trunc_algs(T, sz, algs; kwargs...)
+        test_eig_trunc_algs(T, sz, algs; kwargs...)
     end
 end
 
@@ -78,7 +78,7 @@ function test_eig_trunc(
         Ac = deepcopy(A)
         Tc = complex(eltype(T))
         # eigenvalues are sorted by ascending real component...
-        D₀ = sort!(eig_vals(A); by = abs, rev = true)
+        D₀ = collect(sort!(eig_vals(A); by = abs, rev = true))
         m = size(A, 1)
         rmin = findfirst(i -> abs(D₀[end - i]) != abs(D₀[end - i - 1]), 1:(m - 2))
         r = length(D₀) - rmin
@@ -150,7 +150,7 @@ function test_eig_trunc_algs(
         Ac = deepcopy(A)
         Tc = complex(eltype(T))
         # eigenvalues are sorted by ascending real component...
-        D₀ = sort!(eig_vals(A; alg); by = abs, rev = true)
+        D₀ = collect(sort!(eig_vals(A; alg); by = abs, rev = true))
         m = size(A, 1)
         rmin = findfirst(i -> abs(D₀[end - i]) != abs(D₀[end - i - 1]), 1:(m - 2))
         r = length(D₀) - rmin
diff --git a/test/testsuite/eigh.jl b/test/testsuite/eigh.jl
index df6e4d6e..087ee734 100644
--- a/test/testsuite/eigh.jl
+++ b/test/testsuite/eigh.jl
@@ -76,50 +76,49 @@ function test_eigh_trunc(
         A = A * A'
         A = project_hermitian!(A)
         Ac = deepcopy(A)
-        if !(T <: Diagonal)
 
-            m = size(A, 1)
-            D₀ = reverse(eigh_vals(A))
-            r = m - 2
-            s = 1 + sqrt(eps(real(eltype(T))))
-            atol = sqrt(eps(real(eltype(T))))
-            # truncrank
-            D1, V1, ϵ1 = @testinferred eigh_trunc(A; trunc = truncrank(r))
-            @test length(diagview(D1)) == r
-            @test isisometric(V1)
-            @test A * V1 ≈ V1 * D1
-            @test opnorm(A - V1 * D1 * V1') ≈ D₀[r + 1]
-            @test ϵ1 ≈ norm(view(D₀, (r + 1):m)) atol = atol
-
-            # trunctol
-            trunc = trunctol(; atol = s * D₀[r + 1])
-            D2, V2, ϵ2 = @testinferred eigh_trunc(A; trunc)
-            @test length(diagview(D2)) == r
-            @test isisometric(V2)
-            @test A * V2 ≈ V2 * D2
-            @test ϵ2 ≈ norm(view(D₀, (r + 1):m)) atol = atol
-
-            #truncerror
-            s = 1 - sqrt(eps(real(eltype(T))))
-            trunc = truncerror(; atol = s * norm(@view(D₀[r:end]), 1), p = 1)
-            D3, V3, ϵ3 = @testinferred eigh_trunc(A; trunc)
-            @test length(diagview(D3)) == r
-            @test A * V3 ≈ V3 * D3
-            @test ϵ3 ≈ norm(view(D₀, (r + 1):m)) atol = atol
-
-            s = 1 - sqrt(eps(real(eltype(T))))
-            trunc = truncerror(; atol = s * norm(@view(D₀[r:end]), 1), p = 1)
-            D4, V4 = @testinferred eigh_trunc_no_error(A; trunc)
-            @test length(diagview(D4)) == r
-            @test A * V4 ≈ V4 * D4
-
-            # test for same subspace
-            @test V1 * (V1' * V2) ≈ V2
-            @test V2 * (V2' * V1) ≈ V1
-            @test V1 * (V1' * V3) ≈ V3
-            @test V3 * (V3' * V1) ≈ V1
-            @test V4 * (V4' * V1) ≈ V1
-        end
+        m = size(A, 1)
+        D₀ = collect(reverse(eigh_vals(A)))
+        r = m - 2
+        s = 1 + sqrt(eps(real(eltype(T))))
+        atol = sqrt(eps(real(eltype(T))))
+        # truncrank
+        D1, V1, ϵ1 = @testinferred eigh_trunc(A; trunc = truncrank(r))
+        @test length(diagview(D1)) == r
+        @test isisometric(V1)
+        @test A * V1 ≈ V1 * D1
+        @test opnorm(A - V1 * D1 * V1') ≈ D₀[r + 1]
+        @test ϵ1 ≈ norm(view(D₀, (r + 1):m)) atol = atol
+
+        # trunctol
+        trunc = trunctol(; atol = s * D₀[r + 1])
+        D2, V2, ϵ2 = @testinferred eigh_trunc(A; trunc)
+        @test length(diagview(D2)) == r
+        @test isisometric(V2)
+        @test A * V2 ≈ V2 * D2
+        @test ϵ2 ≈ norm(view(D₀, (r + 1):m)) atol = atol
+
+        #truncerror
+        s = 1 - sqrt(eps(real(eltype(T))))
+        trunc = truncerror(; atol = s * norm(@view(D₀[r:end]), 1), p = 1)
+        D3, V3, ϵ3 = @testinferred eigh_trunc(A; trunc)
+        @test length(diagview(D3)) == r
+        @test A * V3 ≈ V3 * D3
+        @test ϵ3 ≈ norm(view(D₀, (r + 1):m)) atol = atol
+
+        s = 1 - sqrt(eps(real(eltype(T))))
+        trunc = truncerror(; atol = s * norm(@view(D₀[r:end]), 1), p = 1)
+        D4, V4 = @testinferred eigh_trunc_no_error(A; trunc)
+        @test length(diagview(D4)) == r
+        @test A * V4 ≈ V4 * D4
+
+        # test for same subspace
+        @test V1 * (V1' * V2) ≈ V2
+        @test V2 * (V2' * V1) ≈ V1
+        @test V1 * (V1' * V3) ≈ V3
+        @test V3 * (V3' * V1) ≈ V1
+        @test V4 * (V4' * V1) ≈ V1
+
         @testset "specify truncation algorithm" begin
             atol = sqrt(eps(real(eltype(T))))
             m4 = 4
@@ -156,7 +155,7 @@ function test_eigh_trunc_algs(
         Ac = deepcopy(A)
 
         m = size(A, 1)
-        D₀ = reverse(eigh_vals(A))
+        D₀ = collect(reverse(eigh_vals(A)))
         r = m - 2
         s = 1 + sqrt(eps(real(eltype(T))))
         # truncrank