diff --git a/implementations/main.cpp b/implementations/main.cpp
index d8abc3c..be86315 100644
--- a/implementations/main.cpp
+++ b/implementations/main.cpp
@@ -68,7 +68,14 @@ namespace {
 constexpr const char* Version = "0.1.0";
 
 bool g_verbose = false;
-int g_frameGapMs = 500;
+// 500 ms was the research harness's pace, chosen so a human could read the
+// transcript scroll by. It is not a design. The matcher rejects the early
+// frames of a correct press and matches several frames in (frames 3 and 8 in
+// the acceptance run), so frames-per-press is what decides a press -- and a
+// lift is only noticed on the NEXT frame, so it is also the latency a user
+// feels. A frame costs four QTEE round trips regardless; the gap on top is
+// pure delay.
+int g_frameGapMs = 40;
 int g_samples = 10;         // common.max_enrolling_samples, as shipped
 std::string g_logDir = "/var/log/fingerprintd";
 std::string g_stateDir = "/var/lib/fingerprintd";
@@ -1242,6 +1249,11 @@ public:
         bool inPress = false, pressMatched = false, pressRejected = false;
         int pressFrames = 0, rescans = 0;
         std::uint32_t pressFid = 0;
+        auto t0 = std::chrono::steady_clock::now();
+        auto msSince = [&](auto t) {
+            return std::chrono::duration_cast<std::chrono::milliseconds>(
+                std::chrono::steady_clock::now() - t).count();
+        };
 
         // The reference frame loop is {QUERY, CAPTURE, REPORT, QUERY, REPORT}.
         // The trailing query acknowledges the trustlet's event state; without
@@ -1300,13 +1312,22 @@ public:
                 out.decided = true; out.matched = true; out.fid = pressFid;
                 std::println("  press {}: {} frames -> MATCH fid={}", out.presses, pressFrames, pressFid);
             }
-            if (g_verbose)
-                std::println("  frame {:3}: metric={:<4}{}{}", i + 1, c.metric,
-                             finger ? " FINGER" : "       ", note);
             SendCommand(app_, ta::Cmd::QueryEventStatus, q);
+            if (g_verbose) {
+                // The IRQ line alongside the metric: if it tracks the finger
+                // under an armed session, lift detection can become an edge
+                // wait instead of a poll.
+                auto irq = sensor_.ReadIrq();
+                std::println("  frame {:3} @{:5}ms: metric={:<4}{} irq={}{}", i + 1,
+                             msSince(t0), c.metric, finger ? " FINGER" : "       ",
+                             irq ? std::to_string(*irq) : "?", note);
+            }
             std::this_thread::sleep_for(std::chrono::milliseconds(g_frameGapMs));
         }
         fingerPresent_.store(false);
+        std::println("  verify loop: {} frames in {} ms ({} ms/frame incl. {} ms gap)",
+                     out.frames, msSince(t0),
+                     out.frames ? msSince(t0) / out.frames : 0, g_frameGapMs);
         if (cancel) {
             SendCommand(app_, ta::Cmd::Cancel, {});
             out.cancelled = true;
@@ -2006,6 +2027,7 @@ int main(int argc, char** argv) {
         if (a == "--enrol") { doEnrol = true; probe = true; }
         if (a == "--cal-save") { doCalSave = true; probe = true; g_verbose = true; }
         if (a.starts_with("--frames=")) frames = std::stoi(std::string(a.substr(9)));
+        if (a.starts_with("--frame-gap=")) g_frameGapMs = std::stoi(std::string(a.substr(12)));
         if (a.starts_with("--log-dir=")) g_logDir = a.substr(10);
         if (a.starts_with("--state-dir=")) g_stateDir = a.substr(12);
         if (a.starts_with("--rescan=")) g_rescan = std::stoi(std::string(a.substr(9)));