diff --git a/piker/ui/_chart.py b/piker/ui/_chart.py
index 7ba23f5b..9b5e2b52 100644
--- a/piker/ui/_chart.py
+++ b/piker/ui/_chart.py
@@ -550,20 +550,36 @@ class ChartPlotWidget(pg.PlotWidget):
         }
         pdi_kwargs.update(_pdi_defaults)
 
+        # curve = pg.PlotCurveItem(
         curve = pg.PlotDataItem(
             y=data[name],
             x=data['index'],
             # antialias=True,
             name=name,
 
+            # XXX: pretty sure this is just more overhead
+            # on data reads and makes graphics rendering no faster
+            # clipToView=True,
+
             # TODO: see how this handles with custom ohlcv bars graphics
             # and/or if we can implement something similar for OHLC graphics
-            # clipToView=True,
-            autoDownsample=True,
-            downsampleMethod='subsample',
+            # autoDownsample=True,
+            # downsample=60,
+            # downsampleMethod='subsample',
 
             **pdi_kwargs,
         )
+
+        # XXX: see explanation for differenct caching modes:
+        # https://stackoverflow.com/a/39410081
+        # seems to only be useful if we don't re-generate the entire
+        # QPainterPath every time
+        # curve.curve.setCacheMode(QtGui.QGraphicsItem.DeviceCoordinateCache)
+
+        # don't ever use this - it's a colossal nightmare of artefacts
+        # and is disastrous for performance.
+        # curve.setCacheMode(QtGui.QGraphicsItem.ItemCoordinateCache)
+
         self.addItem(curve)
 
         # register curve graphics and backing array for name
@@ -689,13 +705,15 @@ class ChartPlotWidget(pg.PlotWidget):
             # figure out x-range in view such that user can scroll "off"
             # the data set up to the point where ``_min_points_to_show``
             # are left.
-            view_len = r - l
+            # view_len = r - l
 
             # TODO: logic to check if end of bars in view
-            extra = view_len - _min_points_to_show
-            begin = self._ohlc[0]['index'] - extra
-            # end = len(self._ohlc) - 1 + extra
-            end = self._ohlc[-1]['index'] - 1 + extra
+            # extra = view_len - _min_points_to_show
+
+            # begin = self._ohlc[0]['index'] - extra
+
+            # # end = len(self._ohlc) - 1 + extra
+            # end = self._ohlc[-1]['index'] - 1 + extra
 
             # XXX: test code for only rendering lines for the bars in view.
             # This turns out to be very very poor perf when scaling out to
@@ -1292,11 +1310,11 @@ async def check_for_new_bars(feed, ohlcv, linked_charts):
         # current bar) and then either write the current bar manually
         # or place a cursor for visual cue of the current time step.
 
-        price_chart.update_ohlc_from_array(
-            price_chart.name,
-            ohlcv.array,
-            just_history=True,
-        )
+        # price_chart.update_ohlc_from_array(
+        #     price_chart.name,
+        #     ohlcv.array,
+        #     just_history=True,
+        # )
 
         # XXX: this puts a flat bar on the current time step
         # TODO: if we eventually have an x-axis time-step "cursor"
diff --git a/piker/ui/_exec.py b/piker/ui/_exec.py
index bbb3633a..360383c3 100644
--- a/piker/ui/_exec.py
+++ b/piker/ui/_exec.py
@@ -83,8 +83,7 @@ class MainWindow(QtGui.QMainWindow):
         """Cancel the root actor asap.
 
         """
-        # raising KBI seems to get intercepted by by Qt so just use the
-        # system.
+        # raising KBI seems to get intercepted by by Qt so just use the system.
         os.kill(os.getpid(), signal.SIGINT)