diff --git a/CMakeLists.txt b/CMakeLists.txt
index d1f9b51..783821c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,7 +67,7 @@ link_directories(
 )
 
 add_executable(inspectrum ${inspectrum_sources})
-qt5_use_modules(inspectrum Widgets)
+qt5_use_modules(inspectrum Widgets Concurrent)
 
 target_link_libraries(inspectrum
     ${Boost_LIBRARIES}
diff --git a/plotview.cpp b/plotview.cpp
index fb66335..e7d85ab 100644
--- a/plotview.cpp
+++ b/plotview.cpp
@@ -46,7 +46,11 @@ PlotView::PlotView(InputSource *input) : cursors(this), tuner(this), viewRange({
 
     iqPlot = createIQPlot(mainSampleSource);
     plots.emplace_back(iqPlot);
-    plots.emplace_back(createQuadratureDemodPlot(static_cast<SampleSource<std::complex<float>>*>(iqPlot->source().get())));
+    auto quadDemodPlot = createQuadratureDemodPlot(static_cast<SampleSource<std::complex<float>>*>(iqPlot->source().get()));
+    plots.emplace_back(quadDemodPlot);
+
+    connect(iqPlot, &TracePlot::repaint, this, &PlotView::repaint);
+    connect(quadDemodPlot, &TracePlot::repaint, this, &PlotView::repaint);
 
     mainSampleSource->subscribe(this);
 }
@@ -136,6 +140,11 @@ void PlotView::invalidateEvent()
     horizontalScrollBar()->setMaximum(mainSampleSource->count());
 }
 
+void PlotView::repaint()
+{
+    viewport()->update();
+}
+
 void PlotView::setCursorSegments(int segments)
 {
     cursors.setSegments(segments);
diff --git a/plotview.h b/plotview.h
index 6096713..2f237f9 100644
--- a/plotview.h
+++ b/plotview.h
@@ -47,6 +47,7 @@ public slots:
     void cursorsMoved();
     void enableCursors(bool enable);
     void invalidateEvent();
+    void repaint();
     void setCursorSegments(int segments);
     void setFFTAndZoom(int fftSize, int zoomLevel);
     void setPowerMin(int power);
diff --git a/traceplot.cpp b/traceplot.cpp
index 265c76f..c88349a 100644
--- a/traceplot.cpp
+++ b/traceplot.cpp
@@ -19,11 +19,12 @@
 
 #include <QPixmapCache>
 #include <QTextStream>
+#include <QtConcurrent>
 #include "samplesource.h"
 #include "traceplot.h"
 
 TracePlot::TracePlot(std::shared_ptr<AbstractSampleSource> source) : sampleSource(source) {
-
+    connect(this, &TracePlot::imageReady, this, &TracePlot::handleImage);
 }
 
 void TracePlot::paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRange)
@@ -52,19 +53,22 @@ void TracePlot::paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRa
 
 QPixmap TracePlot::getTile(off_t tileID, off_t sampleCount)
 {
-    QPixmap pixmap;
+    QPixmap pixmap(tileWidth, height());
     QString key;
     QTextStream(&key) << "traceplot_" << this << "_" << tileID << "_" << sampleCount;
     if (QPixmapCache::find(key, &pixmap))
         return pixmap;
 
-    auto image = drawTile(QRect(0, 0, tileWidth, height()), {tileID * sampleCount, (tileID + 1) * sampleCount});
-    pixmap = QPixmap::fromImage(image);
-    QPixmapCache::insert(key, pixmap);
+    if (!tasks.contains(key)) {
+        range_t<off_t> sampleRange{tileID * sampleCount, (tileID + 1) * sampleCount};
+        QtConcurrent::run(this, &TracePlot::drawTile, key, QRect(0, 0, tileWidth, height()), sampleRange);
+        tasks.insert(key);
+    }
+    pixmap.fill(Qt::transparent);
     return pixmap;
 }
 
-QImage TracePlot::drawTile(const QRect &rect, range_t<off_t> sampleRange)
+void TracePlot::drawTile(QString key, const QRect &rect, range_t<off_t> sampleRange)
 {
     QImage image(rect.size(), QImage::Format_ARGB32);
     image.fill(Qt::transparent);
@@ -79,7 +83,7 @@ QImage TracePlot::drawTile(const QRect &rect, range_t<off_t> sampleRange)
     if (auto src = dynamic_cast<SampleSource<std::complex<float>>*>(sampleSource.get())) {
         auto samples = src->getSamples(firstSample, length);
         if (samples == nullptr)
-            return image;
+            return;
 
         painter.setPen(Qt::red);
         plotTrace(painter, rect, reinterpret_cast<float*>(samples.get()), length, 2);
@@ -90,7 +94,7 @@ QImage TracePlot::drawTile(const QRect &rect, range_t<off_t> sampleRange)
     } else if (auto src = dynamic_cast<SampleSource<float>*>(sampleSource.get())) {
         auto samples = src->getSamples(firstSample, length);
         if (samples == nullptr)
-            return image;
+            return;
 
         painter.setPen(Qt::green);
         plotTrace(painter, rect, samples.get(), length, 1);
@@ -98,7 +102,15 @@ QImage TracePlot::drawTile(const QRect &rect, range_t<off_t> sampleRange)
     	throw std::runtime_error("TracePlot::paintMid: Unsupported source type");
     }
 
-    return image;
+    emit imageReady(key, image);
+}
+
+void TracePlot::handleImage(QString key, QImage image)
+{
+    auto pixmap = QPixmap::fromImage(image);
+    QPixmapCache::insert(key, pixmap);
+    tasks.remove(key);
+    emit repaint();
 }
 
 void TracePlot::plotTrace(QPainter &painter, const QRect &rect, float *samples, off_t count, int step = 1)
diff --git a/traceplot.h b/traceplot.h
index 2b1bd6d..6f2da7f 100644
--- a/traceplot.h
+++ b/traceplot.h
@@ -33,11 +33,19 @@ public:
     void paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);
     std::shared_ptr<AbstractSampleSource> source() { return sampleSource; };
 
+signals:
+	void imageReady(QString key, QImage image);
+	void repaint();
+
+public slots:
+	void handleImage(QString key, QImage image);
+
 private:
+	QSet<QString> tasks;
 	const int tileWidth = 1000;
 	std::shared_ptr<AbstractSampleSource> sampleSource;
 
 	QPixmap getTile(off_t tileID, off_t sampleCount);
-	QImage drawTile(const QRect &rect, range_t<off_t> sampleRange);
+	void drawTile(QString key, const QRect &rect, range_t<off_t> sampleRange);
 	void plotTrace(QPainter &painter, const QRect &rect, float *samples, off_t count, int step);
 };