diff --git a/tests/tests/swfs/avm1/bitmap_data_pixeldissolve/test.toml b/tests/tests/swfs/avm1/bitmap_data_pixeldissolve/test.toml
index dbee897f5863d..339627584a1eb 100644
--- a/tests/tests/swfs/avm1/bitmap_data_pixeldissolve/test.toml
+++ b/tests/tests/swfs/avm1/bitmap_data_pixeldissolve/test.toml
@@ -1 +1,2 @@
 num_frames = 1
+is_slow = true
diff --git a/tests/tests/swfs/avm1/from_shumway/depth/test.toml b/tests/tests/swfs/avm1/from_shumway/depth/test.toml
index a5fc65ec0feaf..3c8e538bfc0d0 100644
--- a/tests/tests/swfs/avm1/from_shumway/depth/test.toml
+++ b/tests/tests/swfs/avm1/from_shumway/depth/test.toml
@@ -1,3 +1,4 @@
 # Test adapted from Shumway at https://github.com/mozilla/shumway/tree/master/test/swfs/avm1/depth
 
-num_frames = 1
\ No newline at end of file
+num_frames = 1
+is_slow = true
diff --git a/tests/tests/swfs/avm1/timeout/test.toml b/tests/tests/swfs/avm1/timeout/test.toml
index 7f99820cdd917..610d57f5c19c0 100644
--- a/tests/tests/swfs/avm1/timeout/test.toml
+++ b/tests/tests/swfs/avm1/timeout/test.toml
@@ -1,4 +1,5 @@
 num_frames = 1
+is_slow = true
 
 [player_options]
-max_execution_duration = { secs = 5, nanos = 0 }
\ No newline at end of file
+max_execution_duration = { secs = 5, nanos = 0 }
diff --git a/tests/tests/swfs/avm2/away3d_advanced_shallow_water_demo/test.toml b/tests/tests/swfs/avm2/away3d_advanced_shallow_water_demo/test.toml
index 3c99103c38664..8b917ab7aebb4 100644
--- a/tests/tests/swfs/avm2/away3d_advanced_shallow_water_demo/test.toml
+++ b/tests/tests/swfs/avm2/away3d_advanced_shallow_water_demo/test.toml
@@ -1,8 +1,9 @@
 num_ticks = 20
+is_slow = true
 
 [image_comparisons.output]
 tolerance = 5
 max_outliers = 389
 
 [player_options]
-with_renderer = { optional = false, sample_count = 1 }
\ No newline at end of file
+with_renderer = { optional = false, sample_count = 1 }
diff --git a/tests/tests/swfs/avm2/bitmapdata_accuracy/test.toml b/tests/tests/swfs/avm2/bitmapdata_accuracy/test.toml
index dbee897f5863d..339627584a1eb 100644
--- a/tests/tests/swfs/avm2/bitmapdata_accuracy/test.toml
+++ b/tests/tests/swfs/avm2/bitmapdata_accuracy/test.toml
@@ -1 +1,2 @@
 num_frames = 1
+is_slow = true
diff --git a/tests/tests/swfs/avm2/bitmapdata_copypixels_blend_over/test.toml b/tests/tests/swfs/avm2/bitmapdata_copypixels_blend_over/test.toml
index 67f15e8639d22..f949c21472762 100644
--- a/tests/tests/swfs/avm2/bitmapdata_copypixels_blend_over/test.toml
+++ b/tests/tests/swfs/avm2/bitmapdata_copypixels_blend_over/test.toml
@@ -1 +1,2 @@
-num_ticks = 1
\ No newline at end of file
+num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/avm2/large_preload_image_from_bytes/test.toml b/tests/tests/swfs/avm2/large_preload_image_from_bytes/test.toml
index 9632177a2c3b7..61b6df2376228 100755
--- a/tests/tests/swfs/avm2/large_preload_image_from_bytes/test.toml
+++ b/tests/tests/swfs/avm2/large_preload_image_from_bytes/test.toml
@@ -1 +1,2 @@
-num_ticks = 4
\ No newline at end of file
+num_ticks = 4
+is_slow = true
diff --git a/tests/tests/swfs/avm2/stage3d_blend/test.toml b/tests/tests/swfs/avm2/stage3d_blend/test.toml
index 35ed4b0baf76e..cdd8b51e7cf92 100644
--- a/tests/tests/swfs/avm2/stage3d_blend/test.toml
+++ b/tests/tests/swfs/avm2/stage3d_blend/test.toml
@@ -1,4 +1,5 @@
 num_frames = 1
+is_slow = true
 
 [image_comparisons.output]
 tolerance = 2
diff --git a/tests/tests/swfs/avm2/stage3d_raytrace/test.toml b/tests/tests/swfs/avm2/stage3d_raytrace/test.toml
index bf2616f701bae..3322ada29a263 100644
--- a/tests/tests/swfs/avm2/stage3d_raytrace/test.toml
+++ b/tests/tests/swfs/avm2/stage3d_raytrace/test.toml
@@ -3,6 +3,7 @@
 # All of the necessary files were copied into this directory.
 
 num_frames = 80
+is_slow = true
 
 [image_comparisons.output]
 tolerance = 1
diff --git a/tests/tests/swfs/from_avmplus/as3/Vector/initializer_large_vector/test.toml b/tests/tests/swfs/from_avmplus/as3/Vector/initializer_large_vector/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/as3/Vector/initializer_large_vector/test.toml
+++ b/tests/tests/swfs/from_avmplus/as3/Vector/initializer_large_vector/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/e4x/Global/e13_1_2_1/test.toml b/tests/tests/swfs/from_avmplus/e4x/Global/e13_1_2_1/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/e4x/Global/e13_1_2_1/test.toml
+++ b/tests/tests/swfs/from_avmplus/e4x/Global/e13_1_2_1/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_2/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_2/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_2/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_2/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_3/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_3/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_3/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_10_3/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_1/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_1/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_1/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_1/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_2/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_2/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_2/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_2/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_3/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_3/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_3/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Expressions/e11_7_3/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Function/apply_001/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Function/apply_001/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Function/apply_001/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Function/apply_001/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_002/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_002/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_002/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_002/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_003/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_003/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_003/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Statements/eregress_74474_003/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u3400_CJKUnifiedIdeographsExtensionA/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u3400_CJKUnifiedIdeographsExtensionA/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u3400_CJKUnifiedIdeographsExtensionA/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u3400_CJKUnifiedIdeographsExtensionA/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u5000_CJKUnifiedIdeographs/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u5000_CJKUnifiedIdeographs/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u5000_CJKUnifiedIdeographs/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u5000_CJKUnifiedIdeographs/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u6000_CJKUnifiedIdeographs/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u6000_CJKUnifiedIdeographs/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u6000_CJKUnifiedIdeographs/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u6000_CJKUnifiedIdeographs/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u7000_CJKUnifiedIdeographs/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u7000_CJKUnifiedIdeographs/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u7000_CJKUnifiedIdeographs/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u7000_CJKUnifiedIdeographs/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u8000_CJKUnifiedIdeographs/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u8000_CJKUnifiedIdeographs/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u8000_CJKUnifiedIdeographs/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u8000_CJKUnifiedIdeographs/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u9000_CJKUnifiedIdeographs/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u9000_CJKUnifiedIdeographs/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/u9000_CJKUnifiedIdeographs/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/u9000_CJKUnifiedIdeographs/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/uA000_YiSyllables/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/uA000_YiSyllables/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/uA000_YiSyllables/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/uA000_YiSyllables/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/uAC00_HangulSyllables/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/uAC00_HangulSyllables/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/uAC00_HangulSyllables/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/uAC00_HangulSyllables/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/ecma3/Unicode/uE000_PrivateUseArea/test.toml b/tests/tests/swfs/from_avmplus/ecma3/Unicode/uE000_PrivateUseArea/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/ecma3/Unicode/uE000_PrivateUseArea/test.toml
+++ b/tests/tests/swfs/from_avmplus/ecma3/Unicode/uE000_PrivateUseArea/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/from_avmplus/mops/mops_basics/test.toml b/tests/tests/swfs/from_avmplus/mops/mops_basics/test.toml
index cf6123969a1d6..f949c21472762 100644
--- a/tests/tests/swfs/from_avmplus/mops/mops_basics/test.toml
+++ b/tests/tests/swfs/from_avmplus/mops/mops_basics/test.toml
@@ -1 +1,2 @@
 num_ticks = 1
+is_slow = true
diff --git a/tests/tests/swfs/visual/shumway_acid_tests/acid_big/test.toml b/tests/tests/swfs/visual/shumway_acid_tests/acid_big/test.toml
index 3ea81b8067ed8..5a87dbf731387 100644
--- a/tests/tests/swfs/visual/shumway_acid_tests/acid_big/test.toml
+++ b/tests/tests/swfs/visual/shumway_acid_tests/acid_big/test.toml
@@ -1,6 +1,7 @@
 # Test adapted from Shumway at https://github.com/mozilla/shumway/tree/master/test/swfs/acid
 
 num_frames = 300
+is_slow = true
 
 [image_comparisons.output]
 tolerance = 50
diff --git a/tests/tests/swfs/visual/shumway_acid_tests/acid_large/test.toml b/tests/tests/swfs/visual/shumway_acid_tests/acid_large/test.toml
index ae028cc41457e..2a6aa213a7c61 100644
--- a/tests/tests/swfs/visual/shumway_acid_tests/acid_large/test.toml
+++ b/tests/tests/swfs/visual/shumway_acid_tests/acid_large/test.toml
@@ -1,6 +1,7 @@
 # Test adapted from Shumway at https://github.com/mozilla/shumway/tree/master/test/swfs/acid
 
 num_frames = 500
+is_slow = true
 
 [image_comparisons.output]
 tolerance = 11