diff --git a/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx b/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx
index c6ceaaa0f5..41a2808b51 100644
--- a/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx
+++ b/tree/dataframe/inc/ROOT/RDF/ActionHelpers.hxx
@@ -825,12 +825,12 @@ public:
    SumHelper(SumHelper &&) = default;
    SumHelper(const SumHelper &) = delete;
    SumHelper(const std::shared_ptr<ResultType> &sumVPtr, const unsigned int nSlots)
-      : fResultSum(sumVPtr), fSums(nSlots, NeutralElement(*sumVPtr, -1))
+      : fResultSum(sumVPtr), fSums(nSlots * 1024, NeutralElement(*sumVPtr, -1))
    {
    }
 
    void InitTask(TTreeReader *, unsigned int) {}
-   void Exec(unsigned int slot, ResultType v) { fSums[slot] += v; }
+   void Exec(unsigned int slot, ResultType v) { fSums[slot * 1024] += v; }
 
    template <typename T, typename std::enable_if<IsContainer<T>::value, int>::type = 0>
    void Exec(unsigned int slot, const T &vs)
diff --git a/tree/dataframe/inc/ROOT/RDF/RCustomColumn.hxx b/tree/dataframe/inc/ROOT/RDF/RCustomColumn.hxx
index f59087a023..8eb1dc9091 100644
--- a/tree/dataframe/inc/ROOT/RDF/RCustomColumn.hxx
+++ b/tree/dataframe/inc/ROOT/RDF/RCustomColumn.hxx
@@ -70,7 +70,7 @@ class RCustomColumn final : public RCustomColumnBase {
    template <std::size_t... S, typename... BranchTypes>
    void UpdateHelper(unsigned int slot, Long64_t entry, std::index_sequence<S...>, TypeList<BranchTypes...>, NoneTag)
    {
-      fLastResults[slot] = fExpression(std::get<S>(fValues[slot]).Get(entry)...);
+      fLastResults[slot * 1024] = fExpression(std::get<S>(fValues[slot]).Get(entry)...);
       // silence "unused parameter" warnings in gcc
       (void)slot;
       (void)entry;
@@ -79,7 +79,7 @@ class RCustomColumn final : public RCustomColumnBase {
    template <std::size_t... S, typename... BranchTypes>
    void UpdateHelper(unsigned int slot, Long64_t entry, std::index_sequence<S...>, TypeList<BranchTypes...>, SlotTag)
    {
-      fLastResults[slot] = fExpression(slot, std::get<S>(fValues[slot]).Get(entry)...);
+      fLastResults[slot * 1024] = fExpression(slot, std::get<S>(fValues[slot]).Get(entry)...);
       // silence "unused parameter" warnings in gcc
       (void)slot;
       (void)entry;
@@ -89,7 +89,7 @@ class RCustomColumn final : public RCustomColumnBase {
    void
    UpdateHelper(unsigned int slot, Long64_t entry, std::index_sequence<S...>, TypeList<BranchTypes...>, SlotAndEntryTag)
    {
-      fLastResults[slot] = fExpression(slot, entry, std::get<S>(fValues[slot]).Get(entry)...);
+      fLastResults[slot * 1024] = fExpression(slot, entry, std::get<S>(fValues[slot]).Get(entry)...);
       // silence "unused parameter" warnings in gcc
       (void)slot;
       (void)entry;
@@ -99,7 +99,7 @@ public:
    RCustomColumn(RLoopManager *lm, std::string_view name, F &&expression, const ColumnNames_t &columns,
                  unsigned int nSlots, const RDFInternal::RBookedCustomColumns &customColumns, bool isDSColumn = false)
       : RCustomColumnBase(lm, name, nSlots, isDSColumn, customColumns), fExpression(std::forward<F>(expression)),
-        fColumnNames(columns), fLastResults(fNSlots), fValues(fNSlots), fIsCustomColumn()
+        fColumnNames(columns), fLastResults(fNSlots * 1024), fValues(fNSlots), fIsCustomColumn()
    {
       const auto nColumns = fColumnNames.size();
       for (auto i = 0u; i < nColumns; ++i)
@@ -117,14 +117,14 @@ public:
       }
    }
 
-   void *GetValuePtr(unsigned int slot) final { return static_cast<void *>(&fLastResults[slot]); }
+   void *GetValuePtr(unsigned int slot) final { return static_cast<void *>(&fLastResults[slot * 1024]); }
 
    void Update(unsigned int slot, Long64_t entry) final
    {
-      if (entry != fLastCheckedEntry[slot]) {
+      if (entry != fLastCheckedEntry[slot * 1024]) {
          // evaluate this filter, cache the result
          UpdateHelper(slot, entry, TypeInd_t(), ColumnTypes_t(), ExtraArgsTag{});
-         fLastCheckedEntry[slot] = entry;
+         fLastCheckedEntry[slot * 1024] = entry;
       }
    }
 
diff --git a/tree/dataframe/src/RCustomColumnBase.cxx b/tree/dataframe/src/RCustomColumnBase.cxx
index 3a123899c5..f770dca442 100644
--- a/tree/dataframe/src/RCustomColumnBase.cxx
+++ b/tree/dataframe/src/RCustomColumnBase.cxx
@@ -48,5 +48,5 @@ std::string RCustomColumnBase::GetName() const
 
 void RCustomColumnBase::InitNode()
 {
-   fLastCheckedEntry = std::vector<Long64_t>(fNSlots, -1);
+   fLastCheckedEntry = std::vector<Long64_t>(fNSlots * 1024, -1);
 }