diff --git a/docs/verb-reference.md b/docs/verb-reference.md
index 3ded8759..db2f96e8 100644
--- a/docs/verb-reference.md
+++ b/docs/verb-reference.md
@@ -3569,7 +3569,7 @@ Write the whole experiment to a file, its definition beside every cell's raw num
 |---|---|---|---|
 | `path` | string | optional, primary | where to write it; empty writes meshbench-experiment.json in the system temporary directory, and a path that cannot be written is refused |
 
-**Answers** `path`, `bytes`. JSON, holding the arms, seeds, senders and timings alongside `results`, which is every cell including the per-second histogram and the at-risk shares, and `summary`, which is the means. It will write an empty one before anything has run.
+**Answers** `path`, `bytes`. JSON, holding the arms, seeds, senders and timings alongside `results`, which is every cell including the per-second histogram, the at-risk shares and `chip`, what each node's radio counted over the cell and how it was set at the end, and `summary`, which is the means. It will write an empty one before anything has run.
 
 **Example** - keep the sweep, wherever the machine puts temporary files
 
diff --git a/docs/verbs.json b/docs/verbs.json
index f76815fa..dafe9da9 100644
--- a/docs/verbs.json
+++ b/docs/verbs.json
@@ -1450,7 +1450,7 @@
         "path",
         "bytes"
       ],
-      "answers": "JSON, holding the arms, seeds, senders and timings alongside `results`, which is every cell including the per-second histogram and the at-risk shares, and `summary`, which is the means. It will write an empty one before anything has run.",
+      "answers": "JSON, holding the arms, seeds, senders and timings alongside `results`, which is every cell including the per-second histogram, the at-risk shares and `chip`, what each node's radio counted over the cell and how it was set at the end, and `summary`, which is the means. It will write an empty one before anything has run.",
       "example": {
         "params": {},
         "what": "keep the sweep, wherever the machine puts temporary files",
diff --git a/internal/app/session/experiment/cell.go b/internal/app/session/experiment/cell.go
index 47456d7e..0e369eae 100644
--- a/internal/app/session/experiment/cell.go
+++ b/internal/app/session/experiment/cell.go
@@ -316,6 +316,7 @@ func runArm(ctx context.Context, s *session.Sim, e *experiment, arm session.ExpA
 	// boot chatter above are receptions too, and a cell that inherited them
 	// would report the mesh coming up rather than the flood it measured.
 	eng.ResetSensitivity()
+	chipBefore := chipBaseline(eng)
 	burstMs := uint32(0)
 
 	// Sends waiting for their moment, when the senders are staggered.
@@ -443,6 +444,7 @@ func runArm(ctx context.Context, s *session.Sim, e *experiment, arm session.ExpA
 	for i := range engine.MarginEdgesDB {
 		out.AtRisk[i] = sens.AtRisk(i)
 	}
+	out.Chip = chipStats(eng, chipBefore)
 	return out
 }
 
diff --git a/internal/app/session/experiment/chipstats.go b/internal/app/session/experiment/chipstats.go
new file mode 100644
index 00000000..d20a912c
--- /dev/null
+++ b/internal/app/session/experiment/chipstats.go
@@ -0,0 +1,114 @@
+package experiment
+
+import (
+	"github.com/MeshBench/meshbench/internal/firmware"
+	"github.com/MeshBench/meshbench/internal/sim/engine"
+)
+
+// ChipStats is what each node's chip saw during a cell, summed and per node.
+//
+// Delivery totals say what the mesh did; these say what the firmware was told.
+// They are the only way to tell a busy channel from a radio that cries busy,
+// and - on a chip that applies IrqMask - a firmware that never enabled an
+// interrupt from one that never had cause to see it. Two builds whose radio
+// drivers differ and whose totals agree are not shown to behave alike until
+// these agree too.
+type ChipStats struct {
+	IRQReads      uint64 `json:"irq_reads"`
+	BusyReads     uint64 `json:"busy_reads"`
+	BusyMs        uint64 `json:"busy_ms"`
+	Spurious      uint64 `json:"spurious"`
+	IRQSuppressed uint64 `json:"irq_suppressed"`
+	// Reporting is how many nodes sent a suppressed count at all. A chip that
+	// ignores the mask sends none, and its total of zero means unknown.
+	Reporting int        `json:"suppressed_reporting"`
+	Nodes     []NodeChip `json:"nodes"`
+}
+
+// NodeChip is what one node's chip counted over the cell, and how it was
+// set when the cell ended.
+type NodeChip struct {
+	Name          string `json:"name"`
+	Kind          string `json:"kind"`
+	IRQReads      uint32 `json:"irq_reads"`
+	BusyReads     uint32 `json:"busy_reads"`
+	BusyMs        uint32 `json:"busy_ms"`
+	Spurious      uint32 `json:"spurious"`
+	IRQSuppressed uint32 `json:"irq_suppressed"`
+	Reported      bool   `json:"suppressed_reported"`
+	IRQMask       uint16 `json:"irq_mask"`
+	SF            uint8  `json:"sf"`
+	BandwidthHz   uint32 `json:"bandwidth_hz"`
+}
+
+// chipBaseline is every running node's chip as the cell's own traffic begins.
+//
+// The chip counts from boot, and the cell's other numbers do not: the ledger
+// and the margin counters both start after the adverts have settled. Without
+// this, the counters would include the mesh coming up while the delivery
+// totals beside them do not, and two arms that booted differently would look
+// as though they flooded differently.
+func chipBaseline(eng *engine.Engine) map[string]firmware.RadioStats {
+	out := map[string]firmware.RadioStats{}
+	for _, n := range eng.Nodes() {
+		if n.Firmware != nil {
+			out[n.Spec().Name] = n.Firmware.Bridge.Stats()
+		}
+	}
+	return out
+}
+
+// chipStats reads every running node's chip since before. Called before the
+// engine closes, while the bridges still hold the last record each node sent.
+func chipStats(eng *engine.Engine, before map[string]firmware.RadioStats) *ChipStats {
+	out := &ChipStats{}
+	for _, n := range eng.Nodes() {
+		if n.Firmware == nil {
+			continue
+		}
+		name := n.Spec().Name
+		out.add(name, string(n.Spec().Kind), since(n.Firmware.Bridge.Stats(), before[name]))
+	}
+	return out
+}
+
+// since is end with its counters measured from start. The mask, the modem
+// settings and whether a suppressed count is kept are what the chip holds at
+// the end, not counts, so they are end's alone.
+func since(end, start firmware.RadioStats) firmware.RadioStats {
+	end.IRQReads = counted(end.IRQReads, start.IRQReads)
+	end.BusyReads = counted(end.BusyReads, start.BusyReads)
+	end.BusyMs = counted(end.BusyMs, start.BusyMs)
+	end.SpuriousUp = counted(end.SpuriousUp, start.SpuriousUp)
+	end.IRQSuppressed = counted(end.IRQSuppressed, start.IRQSuppressed)
+	return end
+}
+
+// counted is how far a counter moved. One that went backwards was restarted
+// with its node, so everything it holds was counted after the baseline;
+// subtracting would wrap to four billion.
+func counted(end, start uint32) uint32 {
+	if end < start {
+		return end
+	}
+	return end - start
+}
+
+// add folds one node's radio record into the cell's counters.
+func (c *ChipStats) add(name, kind string, r firmware.RadioStats) {
+	c.IRQReads += uint64(r.IRQReads)
+	c.BusyReads += uint64(r.BusyReads)
+	c.BusyMs += uint64(r.BusyMs)
+	c.Spurious += uint64(r.SpuriousUp)
+	if r.SuppressedReported {
+		c.IRQSuppressed += uint64(r.IRQSuppressed)
+		c.Reporting++
+	}
+	c.Nodes = append(c.Nodes, NodeChip{
+		Name: name, Kind: kind,
+		IRQReads: r.IRQReads, BusyReads: r.BusyReads, BusyMs: r.BusyMs,
+		Spurious: r.SpuriousUp, IRQSuppressed: r.IRQSuppressed,
+		Reported: r.SuppressedReported, IRQMask: r.IRQMask,
+		SF: r.SF, BandwidthHz: r.BandwidthHz,
+	})
+}
diff --git a/internal/app/session/experiment/chipstats_test.go b/internal/app/session/experiment/chipstats_test.go
new file mode 100644
index 00000000..a69ee84e
--- /dev/null
+++ b/internal/app/session/experiment/chipstats_test.go
@@ -0,0 +1,95 @@
+package experiment
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/MeshBench/meshbench/internal/firmware"
+)
+
+// A cell sums every node's radio counters and keeps one row per node, so two
+// arms whose delivery totals agree can still be told apart by what each
+// firmware was told.
+func TestACellSumsEveryNodesChipAndKeepsEachRow(t *testing.T) {
+	var c ChipStats
+	c.add("A", "companion", firmware.RadioStats{
+		IRQReads: 100, BusyReads: 10, BusyMs: 500, IRQMask: 0x0272,
+		IRQSuppressed: 7, SuppressedReported: true, SF: 8, BandwidthHz: 62500,
+	})
+	c.add("B", "simple-repeater", firmware.RadioStats{
+		IRQReads: 50, BusyReads: 5, BusyMs: 250, IRQMask: 0x0276,
+		IRQSuppressed: 3, SuppressedReported: true, SF: 8, BandwidthHz: 62500,
+	})
+	if c.IRQReads != 150 || c.BusyReads != 15 || c.BusyMs != 750 {
+		t.Errorf("sums: reads %d busy %d busy_ms %d, want 150 15 750", c.IRQReads, c.BusyReads, c.BusyMs)
+	}
+	if c.IRQSuppressed != 10 || c.Reporting != 2 {
+		t.Errorf("suppressed %d from %d nodes, want 10 from 2", c.IRQSuppressed, c.Reporting)
+	}
+	if len(c.Nodes) != 2 || c.Nodes[1].Name != "B" || c.Nodes[1].IRQMask != 0x0276 {
+		t.Errorf("per-node rows: %+v", c.Nodes)
+	}
+}
+
+// A chip that does not count suppressed events adds nothing to the total and
+// is not counted as reporting, so a total of zero is not mistaken for a count
+// of zero.
+func TestAChipThatDoesNotCountIsNotCountedAsReporting(t *testing.T) {
+	var c ChipStats
+	c.add("old", "simple-repeater", firmware.RadioStats{IRQReads: 20, IRQSuppressed: 9})
+	if c.IRQSuppressed != 0 || c.Reporting != 0 {
+		t.Errorf("suppressed %d from %d nodes, want 0 from 0", c.IRQSuppressed, c.Reporting)
+	}
+	if c.Nodes[0].Reported {
+		t.Error("the row says the chip reported a count it does not keep")
+	}
+}
+
+// The counters reach the export under "chip", beside the cell's other numbers.
+func TestTheExportCarriesEachCellsChipCounters(t *testing.T) {
+	r := Result{Arm: "a", Chip: &ChipStats{IRQReads: 1, Nodes: []NodeChip{{Name: "A"}}}}
+	raw, err := json.Marshal(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	var back map[string]any
+	if err := json.Unmarshal(raw, &back); err != nil {
+		t.Fatal(err)
+	}
+	chip, ok := back["chip"].(map[string]any)
+	if !ok || chip["irq_reads"] != float64(1) {
+		t.Errorf("export row: %s", raw)
+	}
+}
+
+// What the chip counted while the mesh came up stays out of the cell, as the
+// boot chatter stays out of its delivery totals; what the chip holds at the end
+// is reported as it stands.
+func TestACellCountsTheChipFromItsBaselineNotFromBoot(t *testing.T) {
+	start := firmware.RadioStats{
+		IRQReads: 40, BusyReads: 4, BusyMs: 200, SpuriousUp: 1, IRQSuppressed: 6,
+		SuppressedReported: true, IRQMask: 0x0272, SF: 8, BandwidthHz: 62500,
+	}
+	end := firmware.RadioStats{
+		IRQReads: 100, BusyReads: 10, BusyMs: 500, SpuriousUp: 3, IRQSuppressed: 9,
+		SuppressedReported: true, IRQMask: 0x0276, SF: 8, BandwidthHz: 62500,
+	}
+	got := since(end, start)
+	if got.IRQReads != 60 || got.BusyReads != 6 || got.BusyMs != 300 ||
+		got.SpuriousUp != 2 || got.IRQSuppressed != 3 {
+		t.Errorf("counters %+v, want 60 6 300 2 3 counted from the baseline", got)
+	}
+	if got.IRQMask != 0x0276 || got.SF != 8 || got.BandwidthHz != 62500 || !got.SuppressedReported {
+		t.Errorf("state %+v, want the chip as it ended", got)
+	}
+}
+
+// A node that restarted mid-cell starts its counters again from zero, so
+// everything it holds came after the baseline. Subtracting the larger figure
+// from before would wrap to four billion.
+func TestANodeThatRestartedMidCellReportsWhatItCountedSince(t *testing.T) {
+	got := since(firmware.RadioStats{IRQReads: 15}, firmware.RadioStats{IRQReads: 40})
+	if got.IRQReads != 15 {
+		t.Errorf("irq_reads %d, want 15", got.IRQReads)
+	}
+}
diff --git a/internal/app/session/experiment/matrix.go b/internal/app/session/experiment/matrix.go
index dcf22ad1..bcbbe476 100644
--- a/internal/app/session/experiment/matrix.go
+++ b/internal/app/session/experiment/matrix.go
@@ -69,6 +69,10 @@ type Result struct {
 	// actually made, so it needs no second arm to compare against and no
 	// assumption about what boosted gain is worth.
 	AtRisk []float64 `json:"at_risk,omitempty"`
+
+	// Chip is what every node's radio counted over the cell, from the same
+	// baseline as the totals above.
+	Chip *ChipStats `json:"chip,omitempty"`
 }
 
 // BuildRef identifies one firmware a cell ran: the version the arm asked for
diff --git a/internal/app/session/experiment/results.verbs.json b/internal/app/session/experiment/results.verbs.json
index 31f1f3d3..049c70a2 100644
--- a/internal/app/session/experiment/results.verbs.json
+++ b/internal/app/session/experiment/results.verbs.json
@@ -45,7 +45,7 @@
       "path",
       "bytes"
     ],
-    "answers": "JSON, holding the arms, seeds, senders and timings alongside `results`, which is every cell including the per-second histogram and the at-risk shares, and `summary`, which is the means. It will write an empty one before anything has run.",
+    "answers": "JSON, holding the arms, seeds, senders and timings alongside `results`, which is every cell including the per-second histogram, the at-risk shares and `chip`, what each node's radio counted over the cell and how it was set at the end, and `summary`, which is the means. It will write an empty one before anything has run.",
     "example": {
       "params": {},
       "what": "keep the sweep, wherever the machine puts temporary files",