diff --git a/src/app.c b/src/app.c
index 827507e0..669c3400 100644
--- a/src/app.c
+++ b/src/app.c
@@ -279,16 +279,14 @@ void sys_app_entry(struct string args_str)
 #endif
 
     /* Startup systems */
-    struct resource_startup_receipt resource_sr = resource_startup();
-    gp_startup();
     struct sock_startup_receipt sock_sr = sock_startup();
     struct host_startup_receipt host_sr = host_startup(&sock_sr);
     struct asset_cache_startup_receipt asset_cache_sr = asset_cache_startup();
     struct ttf_startup_receipt ttf_sr = ttf_startup();
-    struct font_startup_receipt font_sr = font_startup(&asset_cache_sr, &ttf_sr, &resource_sr);
-    struct sprite_startup_receipt sprite_sr = sprite_startup(&resource_sr);
+    struct font_startup_receipt font_sr = font_startup(&asset_cache_sr, &ttf_sr);
+    struct sprite_startup_receipt sprite_sr = sprite_startup();
     struct mixer_startup_receipt mixer_sr = mixer_startup();
-    struct sound_startup_receipt sound_sr = sound_startup(&asset_cache_sr, &resource_sr);
+    struct sound_startup_receipt sound_sr = sound_startup(&asset_cache_sr);
     struct draw_startup_receipt draw_sr = draw_startup(&font_sr);
     struct sim_startup_receipt sim_sr = sim_startup();
     struct playback_startup_receipt playback_sr = playback_startup(&mixer_sr);
diff --git a/src/app.h b/src/app.h
index cd95a058..1f553dd3 100644
--- a/src/app.h
+++ b/src/app.h
@@ -1,14 +1,6 @@
 #ifndef APP_H
 #define APP_H
 
-enum app_dedicated_worker_id {
-    APP_DEDICATED_WORKER_ID_USER    = 0,
-    APP_DEDICATED_WORKER_ID_SIM     = 1,
-    APP_DEDICATED_WORKER_ID_AUDIO   = 2,
-
-    NUM_APP_DEDICATED_WORKERS
-};
-
 struct string app_write_path_cat(struct arena *arena, struct string filename);
 
 void app_exit(void);
diff --git a/src/font.c b/src/font.c
index 36a8463f..d2b6ddd7 100644
--- a/src/font.c
+++ b/src/font.c
@@ -40,12 +40,10 @@ GLOBAL struct {
  * ========================== */
 
 struct font_startup_receipt font_startup(struct asset_cache_startup_receipt *asset_cache_sr,
-                                         struct ttf_startup_receipt *ttf_sr,
-                                         struct resource_startup_receipt *resource_sr)
+                                         struct ttf_startup_receipt *ttf_sr)
 {
     (UNUSED)asset_cache_sr;
     (UNUSED)ttf_sr;
-    (UNUSED)resource_sr;
 
     G.params.arena = arena_alloc(GIBI(64));
 
diff --git a/src/font.h b/src/font.h
index 45933ecf..73e3b96b 100644
--- a/src/font.h
+++ b/src/font.h
@@ -6,7 +6,6 @@
 struct asset;
 struct asset_cache_startup_receipt;
 struct ttf_startup_receipt;
-struct resource_startup_receipt;
 
 struct font_glyph {
     f32 off_x;
@@ -29,8 +28,7 @@ struct font {
 
 struct font_startup_receipt { i32 _; };
 struct font_startup_receipt font_startup(struct asset_cache_startup_receipt *asset_cache_sr,
-                                         struct ttf_startup_receipt *ttf_sr,
-                                         struct resource_startup_receipt *resource_sr);
+                                         struct ttf_startup_receipt *ttf_sr);
 
 struct asset *font_load_asset(struct string path, f32 point_size, b32 wait);
 struct font *font_load_async(struct string path, f32 point_size);
diff --git a/src/sound.c b/src/sound.c
index 3a9c024b..07021d04 100644
--- a/src/sound.c
+++ b/src/sound.c
@@ -33,11 +33,9 @@ GLOBAL struct {
  * Startup
  * ========================== */
 
-struct sound_startup_receipt sound_startup(struct asset_cache_startup_receipt *asset_cache_sr,
-                                           struct resource_startup_receipt *resource_sr)
+struct sound_startup_receipt sound_startup(struct asset_cache_startup_receipt *asset_cache_sr)
 {
     (UNUSED)asset_cache_sr;
-    (UNUSED)resource_sr;
 
     G.params.arena = arena_alloc(GIBI(64));
 
diff --git a/src/sound.h b/src/sound.h
index 41872b9a..ad00b820 100644
--- a/src/sound.h
+++ b/src/sound.h
@@ -6,7 +6,6 @@
 
 struct asset;
 struct asset_cache_startup_receipt;
-struct resource_startup_receipt;
 
 struct sound {
     u32 flags;
@@ -14,8 +13,7 @@ struct sound {
 };
 
 struct sound_startup_receipt { i32 _; };
-struct sound_startup_receipt sound_startup(struct asset_cache_startup_receipt *asset_cache_sr,
-                                           struct resource_startup_receipt *resource_sr);
+struct sound_startup_receipt sound_startup(struct asset_cache_startup_receipt *asset_cache_sr);
 
 struct asset *sound_load_asset(struct string path, u32 flags, b32 wait);
 struct sound *sound_load_async(struct string path, u32 flags);
diff --git a/src/sprite.c b/src/sprite.c
index 6c5de8e6..0e9e832e 100644
--- a/src/sprite.c
+++ b/src/sprite.c
@@ -208,10 +208,8 @@ INTERNAL SYS_JOB_DEF(sprite_evictor_job, _);
 INTERNAL RESOURCE_WATCH_CALLBACK_FUNC_DEF(sprite_resource_watch_callback, info);
 #endif
 
-struct sprite_startup_receipt sprite_startup(struct resource_startup_receipt *resource_sr)
+struct sprite_startup_receipt sprite_startup(void)
 {
-    (UNUSED)resource_sr;
-
     G.perm_arena = arena_alloc(MEBI(1));
     {
         /* Init loading texture */
diff --git a/src/sprite.h b/src/sprite.h
index 3f2946e1..a3a71964 100644
--- a/src/sprite.h
+++ b/src/sprite.h
@@ -3,7 +3,6 @@
 
 #include "util.h"
 
-struct resource_startup_receipt;
 struct sprite_sheet_span;
 struct sprite_sheet_slice_group;
 
@@ -12,7 +11,7 @@ struct sprite_sheet_slice_group;
  * ========================== */
 
 struct sprite_startup_receipt { i32 _; };
-struct sprite_startup_receipt sprite_startup(struct resource_startup_receipt *resource_sr);
+struct sprite_startup_receipt sprite_startup(void);
 
 /* ========================== *
  * Tag
diff --git a/src/sys.h b/src/sys.h
index a3e0eba0..43de5908 100644
--- a/src/sys.h
+++ b/src/sys.h
@@ -434,16 +434,12 @@ struct sys_window_settings {
     i32 floating_height;
 };
 
-struct sys_window_event_job_sig {
-    struct sys_window *window;
-    struct sys_event event;
-};
-
 struct sys_window_present_job_sig {
     struct sys_window *window;
+    struct sys_event_array events;
 };
 
-struct sys_window *sys_window_alloc(sys_job_func *event_job, sys_job_func *present_job);
+struct sys_window *sys_window_alloc(sys_job_func *present_job);
 void sys_window_release(struct sys_window *sys_window);
 
 void sys_window_update_settings(struct sys_window *sys_window, struct sys_window_settings *settings);
diff --git a/src/sys_win32.c b/src/sys_win32.c
index ee7799f9..e8940f7c 100644
--- a/src/sys_win32.c
+++ b/src/sys_win32.c
@@ -9,6 +9,7 @@
 #include "util.h"
 #include "uni.h"
 #include "gp.h"
+#include "resource.h"
 
 #pragma warning(push, 0)
 # define UNICODE
@@ -48,7 +49,6 @@
 
 #define MAX_EXIT_FUNCS 1024
 
-
 /* Arbitrary threshold for determining when to fall back from a looped WakeByAddressSingle to WakeByAddressAll */
 #define WAKE_ALL_THRESHOLD 8
 
@@ -105,7 +105,10 @@ struct win32_window {
 
     struct gp_swapchain *swapchain;
 
-    sys_job_func *event_job;
+    struct snc_mutex event_arena_swp_mutex;
+    i32 current_event_arena_index;
+    struct arena *event_arenas[2];
+
     sys_job_func *present_job;
 
     struct sys_thread *event_thread;
@@ -887,7 +890,7 @@ INTERNAL SYS_THREAD_DEF(job_worker_entry, worker_ctx_arg)
         void *job_sig = 0;
         struct snc_counter *job_counter = 0;
         {
-            __profnc("Pull job", RGB32_F(0.75, 0.75, 0));
+            //__profnc("Pull job", RGB32_F(0.75, 0.75, 0));
             for (u32 queue_index = 0; queue_index < countof(queues) && !job_func; ++queue_index) {
                 struct job_queue *queue = queues[queue_index];
                 if (queue) {
@@ -1121,7 +1124,7 @@ INTERNAL SYS_THREAD_DEF(job_worker_entry, worker_ctx_arg)
         {
             shutdown = atomic_i32_fetch(&G.workers_shutdown.v);
             while (atomic_i64_fetch(&G.num_jobs_in_queue.v) <= 0 && !shutdown) {
-                __profnc("Wait for job", RGB32_F(0.75, 0.75, 0));
+                //__profnc("Wait for job", RGB32_F(0.75, 0.75, 0));
                 snc_cv_wait(&G.workers_wake_cv, &wake_lock);
                 shutdown = atomic_i32_fetch(&G.workers_shutdown.v);
             }
@@ -2203,14 +2206,13 @@ INTERNAL void win32_window_wake(struct win32_window *window);
 
 INTERNAL void win32_window_process_event(struct win32_window *window, struct sys_event event)
 {
-    if (window->event_job) {
-        __prof;
-        struct snc_counter counter = ZI;
-        struct sys_window_event_job_sig sig = ZI;
-        sig.window = (struct sys_window *)window;
-        sig.event = event;
-        sys_run(1, window->event_job, &sig, SYS_PRIORITY_NORMAL, &counter);
-        snc_counter_wait(&counter);
+    __prof;
+    if (window->present_job) {
+        struct snc_lock lock = snc_lock_e(&window->event_arena_swp_mutex);
+        {
+            *arena_push(window->event_arenas[window->current_event_arena_index], struct sys_event) = event;
+        }
+        snc_unlock(&lock);
     }
 }
 
@@ -2350,16 +2352,31 @@ INTERNAL SYS_THREAD_DEF(window_present_thread_entry_point, arg)
             gp_swapchain_wait(window->swapchain);
         }
         {
-            struct snc_counter counter = ZI;
-            struct sys_window_present_job_sig sig = ZI;
-            sig.window = (struct sys_window *)window;
-            sys_run(1, window->present_job, &sig, SYS_PRIORITY_HIGH, &counter);
-            snc_counter_wait(&counter);
+            i32 event_arena_index = 0;
+            {
+                struct snc_lock lock = snc_lock_e(&window->event_arena_swp_mutex);
+                event_arena_index = window->current_event_arena_index;
+                window->current_event_arena_index = 1 - window->current_event_arena_index;
+                snc_unlock(&lock);
+            }
+            struct arena *events_arena = window->event_arenas[event_arena_index];
+            struct sys_event_array events = ZI;
+            events.count = events_arena->pos / sizeof(struct sys_event);
+            events.events = (struct sys_event *)arena_base(events_arena);
+            {
+                struct snc_counter counter = ZI;
+                struct sys_window_present_job_sig sig = ZI;
+                sig.window = (struct sys_window *)window;
+                sig.events = events;
+                sys_run(1, window->present_job, &sig, SYS_PRIORITY_HIGH, &counter);
+                snc_counter_wait(&counter);
+            }
+            arena_reset(events_arena);
         }
     }
 }
 
-INTERNAL struct win32_window *win32_window_alloc(sys_job_func *event_job, sys_job_func *present_job)
+INTERNAL struct win32_window *win32_window_alloc(sys_job_func *present_job)
 {
     struct win32_window *window = 0;
     {
@@ -2373,10 +2390,17 @@ INTERNAL struct win32_window *win32_window_alloc(sys_job_func *event_job, sys_jo
         snc_unlock(&lock);
     }
     MEMZERO_STRUCT(window);
-    window->event_job = event_job;
     window->present_job = present_job;
 
+    if (present_job) {
+        window->event_arenas[0] = arena_alloc(GIBI(64));
+        window->event_arenas[1] = arena_alloc(GIBI(64));
+    }
+
     /* Start window event thread */
+    /* NOTE: This thread must finish building for the window to actually be
+     * created and receive a HWND, because on Windows a the event proc must run on
+     * the same thread that created the window. */
     snc_counter_add(&window->ready_fence, 1);
     window->event_thread = sys_thread_alloc(&window_event_thread_entry_point, window, LIT("Window event thread"), PROF_THREAD_GROUP_WINDOW);
     snc_counter_wait(&window->ready_fence);
@@ -2387,25 +2411,25 @@ INTERNAL struct win32_window *win32_window_alloc(sys_job_func *event_job, sys_jo
         window->present_thread = sys_thread_alloc(&window_present_thread_entry_point, window, LIT("Window present thread"), PROF_THREAD_GROUP_WINDOW);
     }
 
-    /* Release swapchain */
-    gp_swapchain_release(window->swapchain);
-
     return window;
 }
 
 INTERNAL void win32_window_release(struct win32_window *window)
 {
-    struct snc_lock lock = snc_lock_e(&G.windows_mutex);
-
-    window->next_free = G.first_free_window;
-    G.first_free_window = window;
-
     /* Stop window threads */
     atomic_i32_fetch_set(&window->shutdown, 1);
     win32_window_wake(window);
     sys_thread_wait_release(window->present_thread);
     sys_thread_wait_release(window->event_thread);
 
+    /* Release swapchain */
+    gp_swapchain_release(window->swapchain);
+
+    struct snc_lock lock = snc_lock_e(&G.windows_mutex);
+    {
+        window->next_free = G.first_free_window;
+        G.first_free_window = window;
+    }
     snc_unlock(&lock);
 }
 
@@ -2769,10 +2793,10 @@ INTERNAL LRESULT CALLBACK win32_window_proc(HWND hwnd, UINT msg, WPARAM wparam,
     return result;
 }
 
-struct sys_window *sys_window_alloc(sys_job_func *event_job, sys_job_func *present_job)
+struct sys_window *sys_window_alloc(sys_job_func *present_job)
 {
     __prof;
-    return (struct sys_window *)win32_window_alloc(event_job, present_job);
+    return (struct sys_window *)win32_window_alloc(present_job);
 }
 
 void sys_window_release(struct sys_window *sys_window)
@@ -3364,6 +3388,10 @@ int CALLBACK wWinMain(_In_ HINSTANCE instance, _In_opt_ HINSTANCE prev_instance,
     /* Start test thread */
     struct sys_thread *test_thread = sys_thread_alloc(test_entry, 0, LIT("Test thread"), PROF_THREAD_GROUP_APP);
 
+    /* Startup systems */
+    resource_startup();
+    gp_startup();
+
     /* ========================== *
      * App thread setup
      * ========================== */
diff --git a/src/user.c b/src/user.c
index 1e39b0a2..d9d0aaea 100644
--- a/src/user.c
+++ b/src/user.c
@@ -192,6 +192,7 @@ GLOBAL READONLY enum user_bind_kind g_binds[SYS_BTN_COUNT] = {
 
 INTERNAL SYS_EXIT_FUNC(user_shutdown);
 INTERNAL LOG_EVENT_CALLBACK_FUNC_DEF(debug_console_log_callback, log);
+INTERNAL SYS_JOB_DEF(user_update_job, _);
 INTERNAL SYS_JOB_DEF(local_sim_job , _);
 
 struct user_startup_receipt user_startup(struct font_startup_receipt *font_sr,
@@ -222,9 +223,6 @@ struct user_startup_receipt user_startup(struct font_startup_receipt *font_sr,
     /* Initialize average dt to a reasonable value */
     G.average_local_to_user_snapshot_publish_dt_ns = NS_FROM_SECONDS(1) / SIM_TICKS_PER_SECOND;
 
-    /* Sys events */
-    G.sys_events_arena = arena_alloc(GIBI(64));
-
     /* User blend clients */
     G.user_client_store = sim_client_store_alloc();
     G.user_unblended_client = sim_client_alloc(G.user_client_store);
@@ -248,7 +246,7 @@ struct user_startup_receipt user_startup(struct font_startup_receipt *font_sr,
     sys_run(1, local_sim_job, 0, SYS_PRIORITY_HIGH, &G.shutdown_job_counters);
     sys_on_exit(&user_shutdown);
 
-    G.window = sys_window_alloc(user_event_job, user_present_job);
+    G.window = sys_window_alloc(user_update_job);
 
     return (struct user_startup_receipt) { 0 };
 }
@@ -263,36 +261,6 @@ INTERNAL SYS_EXIT_FUNC(user_shutdown)
     snc_counter_wait(&G.shutdown_job_counters);
 }
 
-/* ========================== *
- * Window -> user communication
- * ========================== */
-
-INTERNAL struct sys_event_array pop_sys_events(struct arena *arena)
-{
-    struct sys_event_array array = ZI;
-    struct snc_lock lock = snc_lock_e(&G.sys_events_mutex);
-    {
-        struct sys_event *src_events = (struct sys_event *)arena_base(G.sys_events_arena);
-        array.count = G.sys_events_arena->pos / sizeof(*src_events);
-        array.events = arena_push_array_no_zero(arena, struct sys_event, array.count);
-        MEMCPY(array.events, src_events, array.count * sizeof(*src_events));
-        arena_reset(G.sys_events_arena);
-    }
-    snc_unlock(&lock);
-    return array;
-}
-
-SYS_JOB_DEF(user_event_job, job)
-{
-    __prof;
-    struct sys_window_event_job_sig *sig = job.sig;
-    struct snc_lock lock = snc_lock_e(&G.sys_events_mutex);
-    {
-        *arena_push_no_zero(G.sys_events_arena, struct sys_event) = sig->event;
-    }
-    snc_unlock(&lock);
-}
-
 /* ========================== *
  * Debug draw
  * ========================== */
@@ -593,11 +561,12 @@ INTERNAL SORT_COMPARE_FUNC_DEF(ent_draw_order_cmp, arg_a, arg_b, udata)
  * Update
  * ========================== */
 
-SYS_JOB_DEF(user_present_job, job)
+SYS_JOB_DEF(user_update_job, job)
 {
     __prof;
     struct sys_window_present_job_sig *sig = job.sig;
     struct sys_window *window = sig->window;
+    struct sys_event_array events = sig->events;
 
     struct arena_temp scratch = scratch_begin_no_conflict();
 
@@ -731,7 +700,6 @@ SYS_JOB_DEF(user_present_job, job)
 
     {
         __profn("Process sys events");
-        struct sys_event_array events = pop_sys_events(scratch.arena);
 
         /* Reset bind pressed / released states */
         for (u32 i = 0; i < countof(G.bind_states); ++i) {
diff --git a/src/user.h b/src/user.h
index 5819f730..c7e69432 100644
--- a/src/user.h
+++ b/src/user.h
@@ -70,7 +70,4 @@ struct user_startup_receipt user_startup(struct font_startup_receipt *font_sr,
                                          struct sim_startup_receipt *sim_sr,
                                          struct string connect_address_str);
 
-SYS_JOB_DEF(user_event_job, job);
-SYS_JOB_DEF(user_present_job, job);
-
 #endif