diff --git a/static/js/app.js b/static/js/app.js
index a5e05a1..3ab4dfb 100644
--- a/static/js/app.js
+++ b/static/js/app.js
@@ -2240,13 +2240,10 @@ document.addEventListener('keydown', e => {
         const continuousKeys = {'j': 1, 'k': -1};
         if (continuousKeys[e.key] !== undefined && !e.repeat) {
           e.preventDefault();
-          const dir = continuousKeys[e.key];
-          const now = performance.now();
-          if (_readerScrollDir !== dir) _readerScrollStartTs = now;
-          _readerScrollDir = dir;
-          _readerScrollLastTs = now;
-          if (!_readerScrollRaf) {
-            _readerScrollRaf = requestAnimationFrame(_readerScrollTick);
+          _readerScrollDir = continuousKeys[e.key];
+          if (!_readerScrollInterval) {
+            _readerScrollLastTs = performance.now();
+            _readerScrollInterval = setInterval(_readerScrollTick, READER_SCROLL_TICK_MS);
           }
         }
         if (e.key === 'd') { e.preventDefault(); contentEl.scrollBy({top:  large / 2, behavior: 'smooth'}); }
@@ -2266,8 +2263,8 @@ document.addEventListener('keydown', e => {
 
 document.addEventListener('keyup', e => {
   if (e.key === 'j' || e.key === 'k') {
-    if (_readerScrollRaf) cancelAnimationFrame(_readerScrollRaf);
-    _readerScrollRaf = null;
+    clearInterval(_readerScrollInterval);
+    _readerScrollInterval = null;
     _readerScrollDir = 0;
   }
 });
@@ -3189,21 +3186,21 @@ let pdfTotalPages = 0;
 let _pdfPageTextBoxCache = {};
 let _pdfRenderGen = 0;
 let _touchStartX = 0;
-let _readerScrollRaf = null;
+let _readerScrollInterval = null;
 let _readerScrollDir = 0;
-let _readerScrollStartTs = 0;
 let _readerScrollLastTs = 0;
-const READER_SCROLL_MIN_SPEED = 700;  // px/s right as j/k is pressed
-const READER_SCROLL_MAX_SPEED = 1800; // px/s once ramped up
-const READER_SCROLL_RAMP_MS = 300;    // time to reach max speed
-function _readerScrollTick(ts) {
-  const dt = ts - _readerScrollLastTs;
-  _readerScrollLastTs = ts;
-  const held = ts - _readerScrollStartTs;
-  const t = Math.min(held / READER_SCROLL_RAMP_MS, 1);
-  const speed = READER_SCROLL_MIN_SPEED + (READER_SCROLL_MAX_SPEED - READER_SCROLL_MIN_SPEED) * t;
-  $('reader-content')?.scrollBy({top: _readerScrollDir * speed * dt / 1000});
-  _readerScrollRaf = requestAnimationFrame(_readerScrollTick);
+const READER_SCROLL_SPEED = 1200;    // constant px/s, no ramp-up
+const READER_SCROLL_TICK_MS = 20;    // fixed cadence, independent of the
+                                      // display's refresh rate — rAF runs at
+                                      // that rate (120/144/165Hz on plenty of
+                                      // laptops), which was driving 2-3x more
+                                      // scrollBy + scroll-listener work per
+                                      // second than intended and read as lag.
+function _readerScrollTick() {
+  const now = performance.now();
+  const dt = now - _readerScrollLastTs;
+  _readerScrollLastTs = now;
+  $('reader-content')?.scrollBy({top: Math.round(_readerScrollDir * READER_SCROLL_SPEED * dt / 1000)});
 }
 let _pinchStartDist = 0;
 let _pinchStartZoom = 100;
diff --git a/static/js/sw.js b/static/js/sw.js
index 4ff96cd..cf4db2c 100644
--- a/static/js/sw.js
+++ b/static/js/sw.js
@@ -2,7 +2,7 @@
  * diora service worker — caches the app shell for offline use.
  */
 
-const CACHE = 'diora-v33';
+const CACHE = 'diora-v34';
 const PODCAST_CACHE = 'diora-podcast-v1';
 const SHELL = [
   '/static/css/app.css',