diff --git a/dm/gfx/nvn/hle_nvn.c b/dm/gfx/nvn/hle_nvn.c
index aba5a4f..700227f 100644
--- a/dm/gfx/nvn/hle_nvn.c
+++ b/dm/gfx/nvn/hle_nvn.c
@@ -1451,12 +1451,14 @@ NVN(nvnTextureViewSetSwizzle, void, NVNtextureView *v, NVNtextureSwizzle r, NVNt
 NVN(nvnColorStateSetAlphaTest, void, NVNcolorState *s, NVNalphaFunc f) { ST(color_st, s)->alpha_func = (uint32_t)f; }
 NVN(nvnColorStateSetLogicOp, void, NVNcolorState *s, NVNlogicOp op) { ST(color_st, s)->logic_op = (uint32_t)op; }
 
-// 设备：组合贴图句柄 = 贴图号 | 采样器号 << 20（与分离句柄同一编码）；计时器数据里的时间戳宿主已是纳秒
-// Device: combined texture handle = texture id | sampler id << 20 (same encoding as the separate handles); the timestamp in counter data is already in nanoseconds on the host
+// 设备：组合贴图句柄 = 贴图号 | 采样器号 << 20（与分离句柄同一编码）
+// Device: combined texture handle = texture id | sampler id << 20 (same encoding as the separate handles)
 NVN(nvnDeviceGetTextureHandle, NVNtextureHandle, const NVNdevice *d, int tex, int samp) { (void)d; return (NVNtextureHandle)((uint64_t)(uint32_t)tex | (uint64_t)(uint32_t)samp << 20); }
-NVN(nvnDeviceGetTimestampInNanoseconds, uint64_t, const NVNdevice *d, const NVNcounterData *c) { (void)d; return c->timestamp; }
-// 当前 GPU 时刻（纳秒）：宿主 GPU 计时与计数器时戳同一时钟源（CLOCK_MONOTONIC） | Current GPU time (ns): the host's GPU timing and counter timestamps share one clock source (CLOCK_MONOTONIC)
-NVN(nvnDeviceGetCurrentTimestampInNanoseconds, uint64_t, const NVNdevice *d) { (void)d; return clock_gettime_nsec_np(CLOCK_MONOTONIC); }
+// 计数器时戳是 19.2 MHz 的 GPU 计数（nvn_mtl.m gpu_ticks：纳秒 × 12 / 625），换回纳秒。原先原样返回，比 GetCurrentTimestampInNanoseconds 小约 52 倍，两者一减就是乱数
+// Counter timestamps are 19.2 MHz GPU ticks (nvn_mtl.m gpu_ticks: ns × 12 / 625); convert back to ns. They used to be returned as is, about 52 times smaller than GetCurrentTimestampInNanoseconds, so subtracting one from the other gave garbage
+NVN(nvnDeviceGetTimestampInNanoseconds, uint64_t, const NVNdevice *d, const NVNcounterData *c) { (void)d; return c->timestamp * 625 / 12; }
+// 当前 GPU 时刻（纳秒）：与计数器时戳同一时钟——客体时钟（guest_ns，nvn_mtl.m gpu_ticks） | Current GPU time (ns): the same clock as the counter timestamps -- the guest clock (guest_ns, nvn_mtl.m gpu_ticks)
+NVN(nvnDeviceGetCurrentTimestampInNanoseconds, uint64_t, const NVNdevice *d) { (void)d; return guest_ns(); }
 NVN(nvnDeviceRegisterFastClearColor, NVNboolean, NVNdevice *d, const float *c, NVNformat f) { (void)d; (void)c; (void)f; return 1; }
 
 // 窗口：活动交换链张数（宿主按创建时张数轮转，只记一次）
diff --git a/dm/gfx/nvn/nvn_mtl.m b/dm/gfx/nvn/nvn_mtl.m
index d6b2887..5516424 100644
--- a/dm/gfx/nvn/nvn_mtl.m
+++ b/dm/gfx/nvn/nvn_mtl.m
@@ -633,7 +633,12 @@ void mtl_sub_event(volatile uint32_t *val, uint32_t mode, uint32_t v) { post((po
 void mtl_sub_counter(uint64_t addr, uint32_t type) { post((post_op){2, NULL, 0, 0, addr, type, NULL}); }
 void mtl_counter_stats(uint64_t rep[32], uint64_t rst[32]) { memcpy(rep, g_cnt_report, sizeof g_cnt_report); memcpy(rst, g_cnt_reset, sizeof g_cnt_reset); }
 
-static uint64_t gpu_ticks(void) { struct timespec t; clock_gettime(CLOCK_MONOTONIC, &t); return ((uint64_t)t.tv_sec * 1000000000ull + t.tv_nsec) * 12 / 625; }
+// 计数器时戳（19.2 MHz）取客体时钟（hle_os.c guest_ns，与 svc GetSystemTick / cntpct 同源）：真机上 GPU 时戳与 CPU 计数同一时基，游戏会拿两者相比。
+// 原先取 CLOCK_MONOTONIC：它在 Mac 睡眠时照走，而客体时钟（mach_absolute_time）不走，两者差出睡眠时长；时戳换成纳秒后马力欧把帧率减半。图形单测里 guest_ns 是返回 0 的弱定义，退回单调时钟
+// Counter timestamps (19.2 MHz) are taken from the guest clock (hle_os.c guest_ns, the same source as svc GetSystemTick / cntpct): on hardware GPU timestamps and the CPU counter share one timebase, and games compare them.
+// They used to come from CLOCK_MONOTONIC, which keeps running while the Mac sleeps while the guest clock (mach_absolute_time) does not, so the two differed by the sleep time; once timestamps were converted to ns, Mario halved its frame rate. In graphics unit tests guest_ns is a weak definition returning 0; fall back to the monotonic clock
+uint64_t guest_ns(void);
+static uint64_t gpu_ticks(void) { uint64_t g = guest_ns(); if (!g) { struct timespec t; clock_gettime(CLOCK_MONOTONIC, &t); g = (uint64_t)t.tv_sec * 1000000000ull + t.tv_nsec; } return g * 12 / 625; }
 
 // ---------- 启动埋点（DM_BOOTPROF=1）：metallib 载入、管线创建（均在提交线程回放中同步发生）、贴图上传、首帧出图 ----------
 // ---------- Boot instrumentation (DM_BOOTPROF=1): metallib loading, pipeline creation (both happen synchronously during replay on the submit thread), texture upload, first-frame present ----------