diff --git a/indra/newview/fsfloaterperformance.cpp b/indra/newview/fsfloaterperformance.cpp
index 4557891a55..3a3ba823ed 100644
--- a/indra/newview/fsfloaterperformance.cpp
+++ b/indra/newview/fsfloaterperformance.cpp
@@ -212,11 +212,12 @@ void LLFloaterPerformance::draw()
 
         auto fps = LLTrace::get_frame_recording().getPeriodMedianPerSec(LLStatViewer::FPS, NUM_PERIODS);
         getChild<LLTextBox>("fps_value")->setValue((S32)llround(fps));
-        auto tot_frame_time_ns = NANOS/fps;
+        // auto tot_frame_time_ns = NANOS/fps;
         auto target_frame_time_ns = NANOS/(targetFPS==0?1:targetFPS);
 
         FSPerfStats::bufferToggleLock.lock(); // prevent toggle for a moment
 
+        auto tot_frame_time_ns = FSPerfStats::raw_to_ns(FSPerfStats::StatsRecorder::getSceneStat(FSPerfStats::StatType_t::RENDER_FRAME));
         // cumulative avatar time (includes idle processing, attachments and base av)
         auto tot_avatar_time_raw = FSPerfStats::StatsRecorder::getSum(AvType, FSPerfStats::StatType_t::RENDER_COMBINED);
         // cumulative avatar render specific time (a bit arbitrary as the processing is too.)
diff --git a/indra/newview/fsperfstats.h b/indra/newview/fsperfstats.h
index 677d4e1419..93a137f86c 100644
--- a/indra/newview/fsperfstats.h
+++ b/indra/newview/fsperfstats.h
@@ -34,7 +34,7 @@
 #include <unordered_map>
 #include <mutex>
 #include "lluuid.h"
-#include "lltimer.h"
+#include "llfasttimer.h"
 #include "blockingconcurrentqueue.h"
 #include "llapp.h"
 #include "fstelemetry.h"
@@ -298,7 +298,7 @@ namespace FSPerfStats
     public:
         StatsRecord stat;
 
-        RecordTime( const LLUUID& av, const LLUUID& id, StatType_t type, bool isRiggedAtt=false):start{LLTimer::getCurrentClockCount()},
+        RecordTime( const LLUUID& av, const LLUUID& id, StatType_t type, bool isRiggedAtt=false):start{LLTrace::BlockTimer::getCPUClockCount64()},
                                                                                               stat{type, ObjTypeDiscriminator, std::move(av), std::move(id), 0, isRiggedAtt}{
             FSZoneC(tracy::Color::Orange);
         #ifdef USAGE_TRACKING
@@ -364,7 +364,7 @@ namespace FSPerfStats
             }
         #endif
 
-            stat.time = LLTimer::getCurrentClockCount() - start;
+            stat.time = LLTrace::BlockTimer::getCPUClockCount64() - start;
             
         #ifdef ATTACHMENT_TRACKING
             static char obstr[36];
@@ -382,9 +382,9 @@ namespace FSPerfStats
 	};
 
     
-    inline double raw_to_ns(U64 raw)    { return (static_cast<double>(raw) * 1000000000.0) * get_timer_info().mClockFrequencyInv; };
-    inline double raw_to_us(U64 raw)    { return (static_cast<double>(raw) *    1000000.0) * get_timer_info().mClockFrequencyInv; };
-    inline double raw_to_ms(U64 raw)    { return (static_cast<double>(raw) *       1000.0) * get_timer_info().mClockFrequencyInv; };
+    inline double raw_to_ns(U64 raw)    { return (static_cast<double>(raw) * 1000000000.0) / (F64)LLTrace::BlockTimer::countsPerSecond(); };
+    inline double raw_to_us(U64 raw)    { return (static_cast<double>(raw) *    1000000.0) / (F64)LLTrace::BlockTimer::countsPerSecond(); };
+    inline double raw_to_ms(U64 raw)    { return (static_cast<double>(raw) *       1000.0) / (F64)LLTrace::BlockTimer::countsPerSecond(); };
 
     using RecordSceneTime = RecordTime<ObjType_t::OT_GENERAL>;
     using RecordAvatarTime = RecordTime<ObjType_t::OT_AVATAR>;