diff --git a/Grid/algorithms/iterative/ConjugateGradientMixedPrec.h b/Grid/algorithms/iterative/ConjugateGradientMixedPrec.h
index 31ac55e0..27fee791 100644
--- a/Grid/algorithms/iterative/ConjugateGradientMixedPrec.h
+++ b/Grid/algorithms/iterative/ConjugateGradientMixedPrec.h
@@ -108,7 +108,10 @@ NAMESPACE_BEGIN(Grid);
     GridStopWatch PrecChangeTimer;
     
     Integer &outer_iter = TotalOuterIterations; //so it will be equal to the final iteration count
-      
+
+    precisionChangeWorkspace pc_wk_sp_to_dp(DoublePrecGrid, SinglePrecGrid);
+    precisionChangeWorkspace pc_wk_dp_to_sp(SinglePrecGrid, DoublePrecGrid);
+    
     for(outer_iter = 0; outer_iter < MaxOuterIterations; outer_iter++){
       //Compute double precision rsd and also new RHS vector.
       Linop_d.HermOp(sol_d, tmp_d);
@@ -123,7 +126,7 @@ NAMESPACE_BEGIN(Grid);
       while(norm * inner_tol * inner_tol < stop) inner_tol *= 2;  // inner_tol = sqrt(stop/norm) ??
 
       PrecChangeTimer.Start();
-      precisionChange(src_f, src_d);
+      precisionChange(src_f, src_d, pc_wk_dp_to_sp);
       PrecChangeTimer.Stop();
       
       sol_f = Zero();
@@ -142,7 +145,7 @@ NAMESPACE_BEGIN(Grid);
       
       //Convert sol back to double and add to double prec solution
       PrecChangeTimer.Start();
-      precisionChange(tmp_d, sol_f);
+      precisionChange(tmp_d, sol_f, pc_wk_sp_to_dp);
       PrecChangeTimer.Stop();
       
       axpy(sol_d, 1.0, tmp_d, sol_d);
diff --git a/tests/solver/Test_dwf_mixedcg_prec.cc b/tests/solver/Test_dwf_mixedcg_prec.cc
new file mode 100644
index 00000000..dc88018e
--- /dev/null
+++ b/tests/solver/Test_dwf_mixedcg_prec.cc
@@ -0,0 +1,122 @@
+    /*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_dwf_cg_prec.cc
+
+    Copyright (C) 2015
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+
+//using namespace std;
+using namespace Grid;
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=12;
+
+  std::cout << GridLogMessage << "::::: NB: to enable a quick bit reproducibility check use the --checksums flag. " << std::endl;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplexD::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+  GridCartesian         * FGrid   = SpaceTimeGrid::makeFiveDimGrid(Ls,UGrid);
+  GridRedBlackCartesian * FrbGrid = SpaceTimeGrid::makeFiveDimRedBlackGrid(Ls,UGrid);
+
+  GridCartesian         * UGrid_f   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplexF::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid_f = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid_f);
+  GridCartesian         * FGrid_f   = SpaceTimeGrid::makeFiveDimGrid(Ls,UGrid_f);
+  GridRedBlackCartesian * FrbGrid_f = SpaceTimeGrid::makeFiveDimRedBlackGrid(Ls,UGrid_f);
+  
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> seeds5({5,6,7,8});
+  GridParallelRNG          RNG5(FGrid);  RNG5.SeedFixedIntegers(seeds5);
+  GridParallelRNG          RNG4(UGrid);  RNG4.SeedFixedIntegers(seeds4);
+
+  LatticeFermionD    src(FGrid); random(RNG5,src);
+  LatticeFermionD result(FGrid); result=Zero();
+  LatticeGaugeFieldD Umu(UGrid);
+  LatticeGaugeFieldF Umu_f(UGrid_f); 
+  
+  SU<Nc>::HotConfiguration(RNG4,Umu);
+
+  precisionChange(Umu_f,Umu);
+  
+  RealD mass=0.1;
+  RealD M5=1.8;
+  DomainWallFermionD Ddwf(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5);
+  DomainWallFermionF Ddwf_f(Umu_f,*FGrid_f,*FrbGrid_f,*UGrid_f,*UrbGrid_f,mass,M5);
+
+  LatticeFermionD    src_o(FrbGrid);
+  LatticeFermionD result_o(FrbGrid);
+  LatticeFermionD result_o_2(FrbGrid);
+  pickCheckerboard(Odd,src_o,src);
+  result_o.Checkerboard() = Odd;
+  result_o = Zero();
+  result_o_2.Checkerboard() = Odd;
+  result_o_2 = Zero();
+
+  SchurDiagMooeeOperator<DomainWallFermionD,LatticeFermionD> HermOpEO(Ddwf);
+  SchurDiagMooeeOperator<DomainWallFermionF,LatticeFermionF> HermOpEO_f(Ddwf_f);
+
+  std::cout << GridLogMessage << "::::::::::::: Starting mixed CG" << std::endl;
+  MixedPrecisionConjugateGradient<LatticeFermionD,LatticeFermionF> mCG(1.0e-8, 10000, 50, FrbGrid_f, HermOpEO_f, HermOpEO);
+  double t1,t2,flops;
+  double MdagMsiteflops = 1452; // Mobius (real coeffs)
+  // CG overhead: 8 inner product, 4+8 axpy_norm, 4+4 linear comb (2 of)
+  double CGsiteflops = (8+4+8+4+4)*Nc*Ns ;
+  std:: cout << " MdagM site flops = "<< 4*MdagMsiteflops<<std::endl;
+  std:: cout << " CG    site flops = "<< CGsiteflops <<std::endl;
+
+  result_o = Zero();
+  t1=usecond();
+  mCG(src_o,result_o);
+  t2=usecond();
+  int iters = mCG.TotalInnerIterations; //Number of inner CG iterations
+  flops = MdagMsiteflops*4*FrbGrid->gSites()*iters;
+  flops+= CGsiteflops*FrbGrid->gSites()*iters;
+  std::cout << " SinglePrecision iterations/sec "<< iters/(t2-t1)*1000.*1000.<<std::endl;
+  std::cout << " SinglePrecision GF/s "<< flops/(t2-t1)/1000.<<std::endl;
+
+  std::cout << GridLogMessage << "::::::::::::: Starting regular CG" << std::endl;
+  ConjugateGradient<LatticeFermionD> CG(1.0e-8,10000);
+  result_o_2 = Zero();
+  t1=usecond();
+  CG(HermOpEO,src_o,result_o_2);
+  t2=usecond();
+  iters = CG.IterationsToComplete;
+  flops = MdagMsiteflops*4*FrbGrid->gSites()*iters; 
+  flops+= CGsiteflops*FrbGrid->gSites()*iters;
+  
+  std::cout << " DoublePrecision iterations/sec "<< iters/(t2-t1)*1000.*1000.<<std::endl;
+  std::cout << " DoublePrecision GF/s "<< flops/(t2-t1)/1000.<<std::endl;
+
+  LatticeFermionD diff_o(FrbGrid);
+  RealD diff = axpy_norm(diff_o, -1.0, result_o, result_o_2);
+
+  std::cout << GridLogMessage << "::::::::::::: Diff between mixed and regular CG: " << diff << std::endl;
+
+  MemoryManager::Print();
+
+  Grid_finalize();
+}