diff --git a/DQM/SiPixelPhase1Heterogeneous/plugins/SiPixelPhase1CompareVertexSoA.cc b/DQM/SiPixelPhase1Heterogeneous/plugins/SiPixelPhase1CompareVertexSoA.cc
index fe824ef013145..0113ea50973d8 100644
--- a/DQM/SiPixelPhase1Heterogeneous/plugins/SiPixelPhase1CompareVertexSoA.cc
+++ b/DQM/SiPixelPhase1Heterogeneous/plugins/SiPixelPhase1CompareVertexSoA.cc
@@ -44,6 +44,9 @@ class SiPixelPhase1CompareVertexSoA : public DQMEDAnalyzer {
   MonitorElement* hchi2oNdof_;
   MonitorElement* hptv2_;
   MonitorElement* hntrks_;
+  MonitorElement* hxdiff_;
+  MonitorElement* hydiff_;
+  MonitorElement* hzdiff_;
 };
 
 //
@@ -129,9 +132,12 @@ void SiPixelPhase1CompareVertexSoA::analyze(const edm::Event& iEvent, const edm:
     auto ndofGPU = vsoaGPU.ndof[closestVtxidx];
     auto chi2GPU = vsoaGPU.chi2[closestVtxidx];
 
-    hx_->Fill(xc, xg);
-    hy_->Fill(yc, yg);
+    hx_->Fill(xc - x0, xg - x0);
+    hy_->Fill(yc - y0, yg - y0);
     hz_->Fill(zc, zg);
+    hxdiff_->Fill(xc - xg);
+    hydiff_->Fill(yc - yg);
+    hzdiff_->Fill(zc - zg);
     hchi2_->Fill(chi2CPU, chi2GPU);
     hchi2oNdof_->Fill(chi2CPU / ndofCPU, chi2GPU / ndofGPU);
     hptv2_->Fill(vsoaCPU.ptv2[sic], vsoaGPU.ptv2[closestVtxidx]);
@@ -146,21 +152,23 @@ void SiPixelPhase1CompareVertexSoA::analyze(const edm::Event& iEvent, const edm:
 void SiPixelPhase1CompareVertexSoA::bookHistograms(DQMStore::IBooker& ibooker,
                                                    edm::Run const& iRun,
                                                    edm::EventSetup const& iSetup) {
-  //std::string top_folder = ""//
   ibooker.cd();
   ibooker.setCurrentFolder(topFolderName_);
 
   // FIXME: all the 2D correlation plots are quite heavy in terms of memory consumption, so a as soon as DQM supports either TH2I or THnSparse
   // these should be moved to a less resource consuming format
   hnVertex_ = ibooker.book2I("nVertex", "# of Vertex;CPU;GPU", 101, -0.5, 100.5, 101, -0.5, 100.5);
-  hx_ = ibooker.book2I("vx", "Vertez x;CPU;GPU", 20, -0.1, 0.1, 20, -0.1, 0.1);
-  hy_ = ibooker.book2I("vy", "Vertez y;CPU;GPU", 20, -0.1, 0.1, 20, -0.1, 0.1);
+  hx_ = ibooker.book2I("vx", "Vertez x - Beamspot x;CPU;GPU", 50, -0.1, 0.1, 50, -0.1, 0.1);
+  hy_ = ibooker.book2I("vy", "Vertez y - Beamspot y;CPU;GPU", 50, -0.1, 0.1, 50, -0.1, 0.1);
   hz_ = ibooker.book2I("vz", "Vertez z;CPU;GPU", 30, -30., 30., 30, -30., 30.);
   hchi2_ = ibooker.book2I("chi2", "Vertex chi-squared;CPU;GPU", 40, 0., 20., 40, 0., 20.);
   hchi2oNdof_ = ibooker.book2I("chi2oNdof", "Vertex chi-squared/Ndof;CPU;GPU", 40, 0., 20., 40, 0., 20.);
   hptv2_ = ibooker.book2I("ptsq", "Vertex p_T squared;CPU;GPU", 200, 0., 200., 200, 0., 200.);
   hntrks_ = ibooker.book2I("ntrk", "#tracks associated;CPU;GPU", 100, -0.5, 99.5, 100, -0.5, 99.5);
   hntrks_ = ibooker.book2I("ntrk", "#tracks associated;CPU;GPU", 100, -0.5, 99.5, 100, -0.5, 99.5);
+  hxdiff_ = ibooker.book1D("vxdiff", ";Vertex x difference (CPU - GPU);#entries", 100, -0.001, 0.001);
+  hydiff_ = ibooker.book1D("vydiff", ";Vertex y difference (CPU - GPU);#entries", 100, -0.001, 0.001);
+  hzdiff_ = ibooker.book1D("vzdiff", ";Vertex z difference (CPU - GPU);#entries", 100, -2.5, 2.5);
 }
 
 void SiPixelPhase1CompareVertexSoA::fillDescriptions(edm::ConfigurationDescriptions& descriptions) {