diff --git a/examples/audio_demo.nes b/examples/audio_demo.nes
index cecd4e0..1041513 100644
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diff --git a/examples/bitwise_ops.nes b/examples/bitwise_ops.nes
index 9f57276..7921e14 100644
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diff --git a/examples/bouncing_ball.nes b/examples/bouncing_ball.nes
index 6970f4a..b769195 100644
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diff --git a/examples/coin_cavern.nes b/examples/coin_cavern.nes
index 6ae24af..c80a9f3 100644
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diff --git a/examples/comparisons.nes b/examples/comparisons.nes
index f98c42d..887c722 100644
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diff --git a/examples/friendly_assets.nes b/examples/friendly_assets.nes
index fe80777..25a0ebb 100644
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diff --git a/examples/function_chain.nes b/examples/function_chain.nes
index 84a89d7..aa6a2d2 100644
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diff --git a/examples/hello_sprite.nes b/examples/hello_sprite.nes
index 03e695c..d6f2d25 100644
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diff --git a/examples/inline_asm_demo.nes b/examples/inline_asm_demo.nes
index fd89a0e..2b8a9cb 100644
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diff --git a/examples/logic_ops.nes b/examples/logic_ops.nes
index d2f40bd..9055961 100644
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diff --git a/examples/match_demo.nes b/examples/match_demo.nes
index 7bdc158..741a551 100644
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diff --git a/examples/metasprite_demo.nes b/examples/metasprite_demo.nes
index 6fcad6f..0baf3d4 100644
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diff --git a/examples/mmc1_banked.nes b/examples/mmc1_banked.nes
index 4c90e57..5cfe88a 100644
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diff --git a/examples/mmc3_per_state_split.nes b/examples/mmc3_per_state_split.nes
index 88a2425..a776605 100644
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diff --git a/examples/nested_structs.nes b/examples/nested_structs.nes
index 5fa3196..c63f0c4 100644
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diff --git a/examples/noise_triangle_sfx.nes b/examples/noise_triangle_sfx.nes
index e4fdf68..e7b884b 100644
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diff --git a/examples/palette_and_background.nes b/examples/palette_and_background.nes
index cd24ddc..df8defb 100644
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diff --git a/examples/platformer.nes b/examples/platformer.nes
index ab75555..d26e6a2 100644
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diff --git a/examples/pong.nes b/examples/pong.nes
index 24e4069..ce53f01 100644
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diff --git a/examples/scanline_split.nes b/examples/scanline_split.nes
index d39912d..03a34f2 100644
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diff --git a/examples/sfx_pitch_envelope.nes b/examples/sfx_pitch_envelope.nes
index 8989f4d..8f646da 100644
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diff --git a/examples/sprite_flicker_demo.nes b/examples/sprite_flicker_demo.nes
index 2481636..51954f3 100644
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diff --git a/examples/sprites_and_palettes.nes b/examples/sprites_and_palettes.nes
index 59e1e2f..d6450df 100644
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diff --git a/examples/state_machine.nes b/examples/state_machine.nes
index 948a84a..b8cbf27 100644
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diff --git a/examples/structs_enums_for.nes b/examples/structs_enums_for.nes
index e9df64d..155d8f3 100644
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diff --git a/examples/two_player.nes b/examples/two_player.nes
index db4c774..167dbd6 100644
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diff --git a/examples/uxrom_banked.nes b/examples/uxrom_banked.nes
index 15844ed..f6178bc 100644
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diff --git a/examples/uxrom_banked_to_banked.nes b/examples/uxrom_banked_to_banked.nes
index fb01da7..7fb8de8 100644
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diff --git a/examples/uxrom_user_banked.nes b/examples/uxrom_user_banked.nes
index 8c98c50..43efe01 100644
Binary files a/examples/uxrom_user_banked.nes and b/examples/uxrom_user_banked.nes differ
diff --git a/examples/war.nes b/examples/war.nes
index 5020e68..2e58168 100644
Binary files a/examples/war.nes and b/examples/war.nes differ
diff --git a/src/codegen/ir_codegen.rs b/src/codegen/ir_codegen.rs
index 516ca0c..3327865 100644
--- a/src/codegen/ir_codegen.rs
+++ b/src/codegen/ir_codegen.rs
@@ -178,6 +178,14 @@ pub struct IrCodeGen<'a> {
     /// masks; runtime divide only survives for non-constant or
     /// non-power-of-two divisors.
     div_used: bool,
+    /// Set to true the first time we lower an `IrOp::DrawSprite`.
+    /// Drives the `__oam_used` marker label. The linker reads this
+    /// to decide whether to splice the OAM DMA into NMI, emit the
+    /// `$FE`-fill OAM shadow init inside `gen_init`'s RAM clear,
+    /// reserve the default smiley tile at CHR tile 0, and keep the
+    /// default palette load. Programs that never `draw` pay zero
+    /// for any of those paths.
+    oam_used: bool,
     /// Source-location markers produced from [`IrOp::SourceLoc`].
     /// Each entry is a `(label_name, span)` pair — the codegen
     /// emits a unique label-definition pseudo-op at the current
@@ -357,6 +365,7 @@ impl<'a> IrCodeGen<'a> {
             ppu_update_used: false,
             mul_used: false,
             div_used: false,
+            oam_used: false,
             source_locs: Vec::new(),
             next_source_loc: 0,
             emit_source_locs: false,
@@ -1387,6 +1396,14 @@ impl<'a> IrCodeGen<'a> {
                 y,
                 frame,
             } => {
+                // Drop the `__oam_used` marker so the linker knows
+                // to emit the OAM DMA + shadow-init + default-sprite
+                // machinery. Programs that never `draw` skip all of
+                // those paths — no DMA cycles per NMI, no $FE OAM
+                // shadow fill, no built-in smiley reserved in CHR,
+                // and the default palette is suppressed too when the
+                // program has no other visual output.
+                self.emit_oam_marker();
                 // Runtime OAM-cursor-based draw. Each frame handler
                 // resets `ZP_OAM_CURSOR` to 0 after the OAM clear; a
                 // `draw` loads the cursor into Y, writes the four
@@ -2073,6 +2090,18 @@ impl<'a> IrCodeGen<'a> {
         }
     }
 
+    /// Emit the `__oam_used` marker label at most once per program.
+    /// Triggered by `IrOp::DrawSprite`. The linker drops the OAM
+    /// DMA + shadow-init + default-sprite-tile paths when this
+    /// marker is absent, shaving cycles out of every NMI and bytes
+    /// out of PRG/CHR for programs that don't draw sprites.
+    fn emit_oam_marker(&mut self) {
+        if !self.oam_used {
+            self.emit_label("__oam_used");
+            self.oam_used = true;
+        }
+    }
+
     /// Emit the MMC3 `__irq_user` handler that dispatches on the
     /// `(current_state, scanline_step)` pair. Supports multiple
     /// `on scanline(N)` handlers per state — they fire in ascending
diff --git a/src/linker/mod.rs b/src/linker/mod.rs
index 2a482c6..261c577 100644
--- a/src/linker/mod.rs
+++ b/src/linker/mod.rs
@@ -411,10 +411,28 @@ impl Linker {
             total_banks,
         ));
 
+        // Whether the program produces any visual output. True if
+        // the user declared a palette / sprite / background, or if
+        // user code contains the `__oam_used` marker (emitted by
+        // `IrOp::DrawSprite`). A purely audio- or compute-only
+        // program is happy to leave the PPU fully silent — no
+        // palette load, no rendering enable, no default-sprite
+        // smiley in CHR — so we gate the reset-time palette
+        // machinery on this flag. See the sprite-chr / OAM-DMA
+        // gates below for the other places it cascades.
+        let has_visual_output = !palettes.is_empty()
+            || !sprites.is_empty()
+            || !backgrounds.is_empty()
+            || has_label(user_code, "__oam_used");
+
         // Load the initial palette. If the program declared any
         // `palette` blocks, use the first one; otherwise fall back
         // to the built-in default palette so sprites show up in a
-        // reasonable colour scheme without any user setup.
+        // reasonable colour scheme without any user setup. Skipped
+        // entirely for programs with no visual output — those leave
+        // palette RAM in its power-on state (undefined on real
+        // hardware, zeros under jsnes / Mesen) which is fine since
+        // nothing gets rendered.
         //
         // IMPORTANT: `gen_init` leaves rendering fully disabled so
         // these $2006/$2007 writes are safe. We re-enable rendering
@@ -425,16 +443,17 @@ impl Linker {
         // about the first 72 bytes of a 1024-byte nametable load.
         if let Some(first_palette) = palettes.first() {
             all_instructions.extend(runtime::gen_initial_palette_load(&first_palette.label()));
-        } else {
-            // No user palette: fall back to a sensible built-in
-            // palette so sprites show up in a reasonable colour
-            // scheme without any user setup. Uses the same indirect
-            // loop loader as the user-palette path (reads a 32-byte
-            // blob through a ZP pointer) — ~20 bytes of code plus a
-            // 32-byte data block that gets spliced in below, versus
-            // the ~170 bytes the old inline-stores path cost. The
-            // data block lives alongside the user palette blobs so
-            // the label resolves in the normal assembly pass.
+        } else if has_visual_output {
+            // No user palette but the program does render something
+            // — fall back to a sensible built-in palette so the
+            // sprites show up in a reasonable colour scheme without
+            // any user setup. Uses the same indirect loop loader as
+            // the user-palette path (reads a 32-byte blob through a
+            // ZP pointer) — ~20 bytes of code plus a 32-byte data
+            // block that gets spliced in below, versus the ~170
+            // bytes the old inline-stores path cost. The data block
+            // lives alongside the user palette blobs so the label
+            // resolves in the normal assembly pass.
             all_instructions.extend(runtime::gen_initial_palette_load(DEFAULT_PALETTE_LABEL));
         }
 
@@ -453,8 +472,13 @@ impl Linker {
         // rendering on. Programs with a declared background get
         // bg+sprites ($1E); programs without get sprites only ($10)
         // to preserve the pre-fix behaviour of example ROMs that
-        // rely on a hidden nametable.
-        all_instructions.extend(runtime::gen_enable_rendering(has_user_background));
+        // rely on a hidden nametable. Programs with no visual
+        // output at all leave PPU_MASK at $00 from `gen_init` —
+        // the PPU stays silent, saves 4 bytes and avoids exposing
+        // an undefined palette on real hardware.
+        if has_visual_output {
+            all_instructions.extend(runtime::gen_enable_rendering(has_user_background));
+        }
 
         // User code (var init + main loop)
         all_instructions.extend(user_code.iter().cloned());
@@ -571,13 +595,13 @@ impl Linker {
         for pal in palettes {
             all_instructions.extend(runtime::gen_data_block(&pal.label(), pal.colors.to_vec()));
         }
-        // When the program has no user palette, splice the built-in
-        // default palette blob under `__default_palette` so the
-        // reset-time loop loader above can resolve it. Programs
-        // that declare a palette fall through the user path and
-        // skip this entirely — saves 32 bytes of ROM data when the
-        // default is unused.
-        if palettes.is_empty() {
+        // When the program needs the built-in default palette (i.e.
+        // it produces visual output but declared no palette of its
+        // own), splice the 32-byte blob under `__default_palette`
+        // so the reset-time loop loader above can resolve it.
+        // Programs that declare a palette OR have no visual output
+        // skip this entirely.
+        if palettes.is_empty() && has_visual_output {
             all_instructions.extend(runtime::gen_data_block(
                 DEFAULT_PALETTE_LABEL,
                 DEFAULT_PALETTE.to_vec(),
diff --git a/src/linker/tests.rs b/src/linker/tests.rs
index 61f7524..47f430c 100644
--- a/src/linker/tests.rs
+++ b/src/linker/tests.rs
@@ -634,14 +634,17 @@ fn link_banked_chr_rom_survives_with_switchable_banks() {
 
 #[test]
 fn default_palette_blob_present_when_no_user_palette() {
-    // With no user palette, the linker emits the shared reset-time
-    // loop loader (which writes twice to `$2006` and loops writing
-    // through `$2007`) and splices a 32-byte `__default_palette`
-    // data block into PRG. The end-to-end ROM should contain the
-    // default palette bytes verbatim at some offset in the fixed
-    // bank.
+    // With no user palette but some visual output (the IR codegen
+    // drops an `__oam_used` marker whenever it lowers a `draw`),
+    // the linker emits the shared reset-time loop loader and
+    // splices a 32-byte `__default_palette` data block into PRG.
+    // The end-to-end ROM should contain the default palette bytes
+    // verbatim at some offset in the fixed bank.
     let linker = Linker::new(Mirroring::Horizontal);
-    let user_code = vec![Instruction::new(NOP, AM::Label("__ir_main_loop".into()))];
+    let user_code = vec![
+        Instruction::new(NOP, AM::Label("__oam_used".into())),
+        Instruction::new(NOP, AM::Label("__ir_main_loop".into())),
+    ];
     let rom = linker.link(&user_code);
 
     // The first four bytes of DEFAULT_PALETTE are {0x0F, 0x00, 0x10,
@@ -654,6 +657,27 @@ fn default_palette_blob_present_when_no_user_palette() {
     assert!(found, "default palette bytes should appear in PRG");
 }
 
+#[test]
+fn default_palette_suppressed_when_no_visual_output() {
+    // An audio- or compute-only program (no palette declared, no
+    // sprites, no backgrounds, no `draw`) shouldn't pay for the
+    // built-in default palette: no `__default_palette` label in
+    // the symbol table, and the 32 bytes of palette data must not
+    // appear anywhere in PRG.
+    let linker = Linker::new(Mirroring::Horizontal);
+    let user_code = vec![Instruction::new(NOP, AM::Label("__ir_main_loop".into()))];
+    let result = linker.link_banked_with_ppu_detailed(&user_code, &[], &[], &[], &[], &[], &[]);
+    assert!(
+        !result.labels.contains_key("__default_palette"),
+        "default palette label must not be defined without visual output"
+    );
+    let prg = &result.rom[16..16 + 16_384];
+    assert!(
+        !prg.windows(4).any(|w| w == [0x0F, 0x00, 0x10, 0x20]),
+        "default palette bytes must not appear in PRG when suppressed"
+    );
+}
+
 #[test]
 fn no_default_palette_blob_when_user_palette_present() {
     // A program that declares its own palette should suppress the
diff --git a/tests/emulator/goldens/audio_demo.audio.hash b/tests/emulator/goldens/audio_demo.audio.hash
index 7fbc913..9ed40e1 100644
--- a/tests/emulator/goldens/audio_demo.audio.hash
+++ b/tests/emulator/goldens/audio_demo.audio.hash
@@ -1 +1 @@
-e064fdf0 132084
+dceef796 132084
diff --git a/tests/emulator/goldens/comparisons.png b/tests/emulator/goldens/comparisons.png
index 9096daf..e0dd216 100644
Binary files a/tests/emulator/goldens/comparisons.png and b/tests/emulator/goldens/comparisons.png differ
diff --git a/tests/emulator/goldens/friendly_assets.audio.hash b/tests/emulator/goldens/friendly_assets.audio.hash
index 0dca2ac..c671279 100644
--- a/tests/emulator/goldens/friendly_assets.audio.hash
+++ b/tests/emulator/goldens/friendly_assets.audio.hash
@@ -1 +1 @@
-68089bdb 132084
+a9a829f7 132084
diff --git a/tests/emulator/goldens/noise_triangle_sfx.audio.hash b/tests/emulator/goldens/noise_triangle_sfx.audio.hash
index ee351f8..435c42c 100644
--- a/tests/emulator/goldens/noise_triangle_sfx.audio.hash
+++ b/tests/emulator/goldens/noise_triangle_sfx.audio.hash
@@ -1 +1 @@
-7b0caf36 132084
+be86c2a2 132084
diff --git a/tests/emulator/goldens/platformer.audio.hash b/tests/emulator/goldens/platformer.audio.hash
index 359b2c8..4bbfe8e 100644
--- a/tests/emulator/goldens/platformer.audio.hash
+++ b/tests/emulator/goldens/platformer.audio.hash
@@ -1 +1 @@
-5cc6d0f5 132084
+c9c2333d 132084
diff --git a/tests/emulator/goldens/pong.audio.hash b/tests/emulator/goldens/pong.audio.hash
index 778c04f..1145110 100644
--- a/tests/emulator/goldens/pong.audio.hash
+++ b/tests/emulator/goldens/pong.audio.hash
@@ -1 +1 @@
-714f679e 132084
+b7d5b53f 132084
diff --git a/tests/emulator/goldens/sfx_pitch_envelope.audio.hash b/tests/emulator/goldens/sfx_pitch_envelope.audio.hash
index a4eb4f4..8d0c60d 100644
--- a/tests/emulator/goldens/sfx_pitch_envelope.audio.hash
+++ b/tests/emulator/goldens/sfx_pitch_envelope.audio.hash
@@ -1 +1 @@
-c1ba0463 132084
+9c881965 132084
diff --git a/tests/emulator/goldens/sfx_pitch_envelope.png b/tests/emulator/goldens/sfx_pitch_envelope.png
index ab3d666..2842948 100644
Binary files a/tests/emulator/goldens/sfx_pitch_envelope.png and b/tests/emulator/goldens/sfx_pitch_envelope.png differ
diff --git a/tests/emulator/goldens/war.audio.hash b/tests/emulator/goldens/war.audio.hash
index 7dc1df6..03cc9de 100644
--- a/tests/emulator/goldens/war.audio.hash
+++ b/tests/emulator/goldens/war.audio.hash
@@ -1 +1 @@
-575adcb6 132084
+b7b5b9a0 132084