docs: add 3090Ti power cap efficiency plot

Add Python script to generate efficiency charts for RTX 3090Ti using
Qwen3.6-27B-UD model.

Author: Pascal Rheaume

docs/img/power-cap-3090Ti-qwen36.py

@@ -0,0 +1,151 @@
+"""Generate 3090Ti power-cap efficiency chart from @pascalrheaume's air-cooled rig.
+
+Source data: 2026-05-14 sweep, single 3090Ti rig (GPU 0 used), air-cooled.
+Engine: mainline llama.cpp (ghcr.io/ggml-org/llama.cpp:server-cuda) +
+Qwen3.6-27B-UD-Q3_K_XL.gguf, decode-single (10s × 2 timed streams)
+
+Sweep methodology: time-bounded streaming bench (10s/direction at each cap).
+Total wall: ~10m 23caps from 230-450W in 10W increments. The time-bounded
+approach (vs token-bounded) makes per-cap wall constant ~23s regardless of cap,
+so total runtime scales linearly with cap count, not throttle severity.
+
+Sampling fields: GPU temp, SM clock, memory clock, power-throttle %, P-state per cap
+(median of in-load samples where util>50%). The extended sweep reveals the full
+efficiency curve up to 450W, with peak efficiency at 310W (0.107 TPS/W) and
+a gradual decline beyond 330W as the GPU draws more power without proportional
+gains in throughput.
+"""
+import matplotlib.pyplot as plt
+
+# (cap_W, narr_TPS, code_TPS, actual_W, gpu_temp_C, sm_clk_MHz, mem_clk_MHz, pwr_throttle_pct, p_state, eff_TPS_per_W) — 23-cap extended sweep
+data = [
+    (230, 19.88, 20.28, 229.69, 63, 750, 10251, 100, "P2", 0.087),
+    (240, 22.07, 21.87, 239.54, 64, 825, 10251, 97, "P2", 0.092),
+    (250, 23.57, 23.17, 249.40, 65, 885, 10251, 100, "P2", 0.095),
+    (260, 25.17, 25.37, 259.04, 65, 975, 10251, 100, "P2", 0.097),
+    (270, 26.77, 26.67, 269.08, 66, 1035, 10251, 100, "P2", 0.099),
+    (280, 28.27, 28.57, 279.07, 67, 1125, 10251, 100, "P2", 0.101),
+    (290, 30.27, 30.27, 289.19, 67, 1215, 10251, 100, "P2", 0.105),
+    (300, 31.77, 31.76, 299.83, 68, 1290, 10251, 100, "P2", 0.106),
+    (310, 33.46, 33.36, 309.38, 69, 1365, 10251, 100, "P2", 0.108),
+    (320, 34.76, 34.86, 319.43, 69, 1470, 10251, 100, "P2", 0.109),
+    (330, 36.36, 36.26, 329.20, 70, 1635, 10251, 100, "P2", 0.110), 
+    (340, 37.36, 37.46, 339.45, 70, 1725, 10251, 100, "P2", 0.110),
+    (350, 38.45, 37.96, 348.79, 71, 1755, 10251, 100, "P2", 0.110), #⭐ sweet spot
+    (360, 38.96, 38.86, 358.66, 72, 1770, 10251, 97, "P2", 0.109),
+    (370, 39.25, 39.16, 368.89, 72, 1815, 10251, 97, "P2", 0.106),
+    (380, 39.46, 39.26, 378.75, 73, 1845, 10251, 100, "P2", 0.104),
+    (390, 39.86, 39.76, 388.42, 73, 1860, 10251, 100, "P2", 0.103),
+    (400, 40.06, 39.66, 398.67, 74, 1875, 10251, 100, "P2", 0.100),
+    (410, 40.06, 40.16, 407.98, 75, 1890, 10251, 97, "P2", 0.098),
+    (420, 40.35, 39.96, 418.79, 75, 1905, 10251, 97, "P2", 0.096),
+    (430, 40.45, 40.36, 428.56, 76, 1920, 10251, 97, "P2", 0.094),
+    (440, 40.55, 40.56, 438.52, 76, 1935, 10251, 100, "P2", 0.092),
+    (450, 40.45, 40.76, 448.35, 77, 1935, 10251, 100, "P2", 0.090), # stock TDP
+]
+
+caps = [d[0] for d in data]
+narr = [d[1] for d in data]
+code = [d[2] for d in data]
+draw = [d[3] for d in data]
+gpu_temp = [d[4] for d in data]
+sm_clk = [d[5] for d in data]
+mem_clk = [d[6] for d in data]
+pwr_throttle = [d[7] for d in data]
+p_state = [d[8] for d in data]
+eff = [d[9] for d in data]
+
+plt.rcParams.update({
+    "font.family": "sans-serif",
+    "font.size": 12,
+    "axes.titlesize": 16,
+    "axes.titleweight": "bold",
+    "axes.labelsize": 13,
+    "figure.facecolor": "white",
+    "axes.facecolor": "white",
+})
+
+fig, ax1 = plt.subplots(figsize=(11, 6.4), dpi=150)
+
+# Left axis: TPS
+color_narr = "#1f77b4"
+color_code = "#2ca02c"
+ax1.plot(caps, narr, "o-", color=color_narr, linewidth=2.2, markersize=6,
+         label="Narrative TPS", zorder=3)
+ax1.plot(caps, code, "s-", color=color_code, linewidth=2.2, markersize=6,
+         label="Code TPS", zorder=3)
+ax1.set_xlabel("Power cap (W)", fontsize=13)
+ax1.set_ylabel("Wall TPS (single-stream, llama.cpp mainline)", fontsize=13)
+ax1.set_xlim(225, 455)
+ax1.set_ylim(14, 43)
+ax1.grid(True, alpha=0.3, zorder=0)
+ax1.tick_params(axis="both", labelsize=11)
+
+# Right axis: TPS/W efficiency
+ax2 = ax1.twinx()
+color_eff = "#d62728"
+ax2.plot(caps, eff, "^--", color=color_eff, linewidth=1.8, markersize=5,
+         alpha=0.9, label="Efficiency (narr TPS/W)", zorder=2)
+ax2.set_ylabel("Efficiency: TPS/W (narrative)", color=color_eff, fontsize=13)
+ax2.tick_params(axis="y", labelcolor=color_eff, labelsize=11)
+ax2.set_ylim(0.07, 0.118)
+
+# Sweet spot annotation: 350W
+ax1.axvline(350,color="goldenrod", linestyle=":", alpha=0.5, linewidth=1.5)
+ax1.annotate(
+    "★ 350W cap\n0.11 TPS/W (best efficiency)\n38.45 narr / 37.98 code\nSM 1755 MHz, 78% of stock TDP",
+    xy=(350, 38),
+    xytext=(320, 28),
+    fontsize=10.5,
+    fontweight="bold",
+    bbox=dict(boxstyle="round,pad=0.4", facecolor="#fff3cd", edgecolor="goldenrod", linewidth=1.2),
+    arrowprops=dict(arrowstyle="->", color="goldenrod", lw=1.5),
+    zorder=4,
+)
+
+# Stock TDP marker at 450W
+ax1.axvline(450, color="#888", linestyle="--", alpha=0.6, linewidth=1.2)
+ax1.annotate(
+    "stock TDP\n450W (GPU 0)",
+    xy=(450, 40.06),
+    xytext=(455, 42),
+    fontsize=10,
+    ha="left",
+    color="#555",
+    fontstyle="italic",
+)
+
+# Title
+ax1.set_title(
+    "RTX 3090Ti Qwen3.6-27B + llama.cpp — extended power-cap efficiency curve",
+    pad=14,
+)
+
+# Subtitle
+fig.text(
+    0.5, 0.92,
+    "1× 3090Ti air-cooled (GPU 0), mainline llama.cpp + Q3_K_XL GGUF, "
+    "time-bounded single-stream, 230-450W sweep  |  data: @pascalrheaume (2026-05-14)",
+    ha="center", fontsize=10, color="#666",
+    style="italic",
+)
+
+# Combined legend
+lines1, labels1 = ax1.get_legend_handles_labels()
+lines2, labels2 = ax2.get_legend_handles_labels()
+ax1.legend(lines1 + lines2, labels1 + labels2,
+           loc="lower right", fontsize=11, framealpha=0.95,
+           edgecolor="#ccc")
+
+# Footer
+fig.text(
+    0.99, 0.01,
+    "github.com/pascalrheaume/club-3090",
+    ha="right", fontsize=9, color="#888", style="italic",
+)
+
+plt.tight_layout(rect=(0, 0.02, 1, 0.92))
+
+out = "/tmp/power_cap_sweep_3090Ti_Qwen36.png"
+plt.savefig(out, dpi=150, bbox_inches="tight", facecolor="white")
+print(f"Saved: {out}")