diff --git a/hbs2-peer/app/BlockDownloadNew.hs b/hbs2-peer/app/BlockDownloadNew.hs
index 984adc5a..6a65d93e 100644
--- a/hbs2-peer/app/BlockDownloadNew.hs
+++ b/hbs2-peer/app/BlockDownloadNew.hs
@@ -155,6 +155,7 @@ queryBlockSizeFromPeer cache e h peer = do
 data BurstMachine =
   BurstMachine
   { _buTimeout  :: Double
+  , _buStart    :: Double
   , _buBurstMax :: Int
   , _buStepUp   :: Double
   , _buStepDown :: Double
@@ -166,6 +167,12 @@ burstMachineAddErrors :: MonadUnliftIO m => BurstMachine -> Int -> m ()
 burstMachineAddErrors BurstMachine{..} n =
   atomically $ modifyTVar _buErrors (+n)
 
+burstMachineReset :: MonadUnliftIO m => BurstMachine -> m ()
+burstMachineReset BurstMachine{..} = do
+  atomically do
+    writeTVar _buCurrent _buStart
+    writeTVar _buErrors 0
+
 newBurstMachine :: MonadUnliftIO m
                 => Double      -- ^ timeout
                 -> Int         -- ^ max burst
@@ -175,7 +182,7 @@ newBurstMachine :: MonadUnliftIO m
                 -> m BurstMachine
 
 newBurstMachine t0 buMax buStart up' down' = do
-  BurstMachine t0 buMax up down
+  BurstMachine t0 bu0 buMax up down
     <$> newTVarIO bu0
     <*> newTVarIO 0
 
@@ -187,6 +194,7 @@ newBurstMachine t0 buMax buStart up' down' = do
 getCurrentBurst :: MonadUnliftIO m => BurstMachine -> m Int
 getCurrentBurst BurstMachine{..} = readTVarIO _buCurrent <&> round
 
+
 runBurstMachine :: MonadUnliftIO m
                 => BurstMachine
                 -> m ()
@@ -652,10 +660,20 @@ downloadDispatcher brains env = flip runContT pure do
 
         loosers <- atomically do
           xs <- readTVar pts <&> HM.toList
-          -- FIXME: filter-stopped-tasks
-          let (alive,dead) = L.partition ( \(x,_) -> HM.member x peers ) xs
-          writeTVar pts (HM.fromList alive)
-          pure dead
+
+          writeTVar pts mempty
+
+          loo <- newTQueue
+
+          for_ xs $ \e@(h,v@(a,_)) -> do
+             running <- isNothing <$> pollSTM a
+             let here = HM.member h peers
+             if running && here then do
+               modifyTVar pts (HM.insert h v)
+             else
+               writeTQueue loo e
+
+          flushTQueue loo
 
         for_ loosers $ \(p, (a, nonce)) -> do
           cancel a
@@ -668,6 +686,7 @@ downloadDispatcher brains env = flip runContT pure do
 
       _errors <- newTVarIO 0
       _avg <- newTVarIO 600
+      _blknum <- newTVarIO 0
 
       _sizeCache <- newTVarIO ( mempty :: HashMap HashRef (Maybe Integer) )
 
@@ -681,10 +700,21 @@ downloadDispatcher brains env = flip runContT pure do
 
       debug $ yellow "Started thread for" <+> pretty p
 
-      -- TODO: sweep size cache!
+      ContT $ withAsync $ forever do
 
-      ContT $ withAsync $ forever $ (>> pause @'Seconds 60) do
+        b0 <- readTVarIO _blknum
+        pause @'Seconds 60
         atomically $ writeTVar _errors 0
+        b1 <- readTVarIO _blknum
+
+        when (b0 == b1) do
+          debug $ blue "Reset burst machine" <+> pretty p
+          burstMachineReset bm
+
+        s <- readTVarIO wip <&> HM.size
+
+        when (s == 0) do
+          atomically $ writeTVar _sizeCache mempty
 
       tsweep <- ContT $ withAsync do
         let hashes = readTVarIO _sizeCache <&> fmap (,60) . HM.keys
@@ -737,7 +767,7 @@ downloadDispatcher brains env = flip runContT pure do
 
                             modifyTVar r (HPSQ.insert h eps dcb)
                             s <- readTVar r <&> HPSQ.size
-                            if s >= 8 then pure () else loop xs
+                            if s >= 4 then pure () else loop xs
 
                      w <- readTVar r <&> HPSQ.findMin
                      case w of
@@ -812,6 +842,7 @@ downloadDispatcher brains env = flip runContT pure do
                 atomically do
                   modifyTVar  btimes ( take 100 . (dtsec :) )
                   writeTVar (dcbDownloaded dcb) True
+                  modifyTVar _blknum succ
                   onBlock hx
 
                 go (PReleaseBlock hx dcb True)