diff --git a/esphome/components/network/__init__.py b/esphome/components/network/__init__.py
index 9a47679ba3..decee27bcf 100644
--- a/esphome/components/network/__init__.py
+++ b/esphome/components/network/__init__.py
@@ -9,9 +9,11 @@ from esphome.components.zephyr import zephyr_add_prj_conf
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_ENABLE_IPV6,
+    CONF_ETHERNET,
     CONF_ID,
     CONF_MIN_IPV6_ADDR_COUNT,
     CONF_PRIORITY,
+    CONF_WIFI,
 )
 from esphome.core import CORE, CoroPriority, coroutine_with_priority
 import esphome.final_validate as fv
@@ -28,6 +30,16 @@ KEY_HIGH_PERFORMANCE_NETWORKING = "high_performance_networking"
 CONF_ENABLE_HIGH_PERFORMANCE = "enable_high_performance"
 CONF_TCP_SEND_BUFFER = "tcp_send_buffer"
 
+# TCP receive window of the optimized lwip tier (PSRAM not guaranteed)
+TCP_WND_OPTIMIZED = 65534
+# Ethernet drivers keep every queued frame in internal RAM, so ethernet-only builds
+# get a window sized for a LAN round trip and the stock lwip input mailbox. Dual
+# wifi + ethernet builds keep wifi's sizes; the ethernet component moves their
+# received frames to PSRAM instead.
+TCP_WND_ETHERNET = 16384
+TCPIP_RECVMBOX_ETHERNET = 32
+TCPIP_RECVMBOX_OPTIMIZED = 64
+
 # lwIP queues at most this many unsent/unacked bytes per TCP socket; the
 # stock ESP-IDF default (5744 bytes) stalls bursty senders like a Bluetooth
 # proxy streaming GATT notifications. Bounds follow the lwIP guidance for the
@@ -166,6 +178,8 @@ def require_high_performance_networking() -> None:
     Configuration is PSRAM-aware:
     - With PSRAM guaranteed: Aggressive settings (512 RX buffers, 512KB TCP windows)
     - Without PSRAM: Conservative optimized settings (64 buffers, 65KB TCP windows)
+    - Ethernet only: 16KB TCP windows regardless of PSRAM, because ESP-IDF
+      ethernet drivers keep received frames in internal RAM
 
     Example:
         from esphome.components import network
@@ -417,8 +431,11 @@ async def to_code(config: ConfigType) -> None:
     if CORE.is_esp32 and should_enable:
         # Check if PSRAM is guaranteed (set by psram component during final validation)
         psram_guaranteed = psram_is_guaranteed()
+        # ESP-IDF ethernet drivers malloc() received frames into internal RAM, so
+        # lwip is never sized for PSRAM on an ethernet-only build.
+        ethernet_only = CONF_ETHERNET in CORE.config and CONF_WIFI not in CORE.config
 
-        if psram_guaranteed:
+        if psram_guaranteed and not ethernet_only:
             _LOGGER.info(
                 "Applying high-performance lwip settings (PSRAM guaranteed): 512KB TCP windows, 512 mailbox sizes"
             )
@@ -451,15 +468,25 @@ async def to_code(config: ConfigType) -> None:
             add_idf_sdkconfig_option("CONFIG_LWIP_TCP_OVERSIZE_MSS", True)
             add_idf_sdkconfig_option("CONFIG_LWIP_TCP_QUEUE_OOSEQ", True)
         else:
+            # Every queued byte is internal RAM on ethernet and a LAN round trip needs
+            # little window; wifi keeps the larger sizes.
+            if ethernet_only:
+                tcp_window, tcpip_mailbox = TCP_WND_ETHERNET, TCPIP_RECVMBOX_ETHERNET
+            else:
+                tcp_window, tcpip_mailbox = TCP_WND_OPTIMIZED, TCPIP_RECVMBOX_OPTIMIZED
             _LOGGER.info(
-                "Applying optimized lwip settings: 65KB TCP windows, 64 mailbox sizes"
+                "Applying optimized lwip settings: %dKB TCP windows, %d entry input mailbox",
+                tcp_window // 1000,
+                tcpip_mailbox,
             )
             # PSRAM not guaranteed - use more conservative, but still optimized settings
             # Based on https://github.com/espressif/esp-idf/blob/release/v5.4/examples/wifi/iperf/sdkconfig.defaults.esp32
+            # The send buffer stays at 65534 on ethernet too: it only fills under outbound
+            # load, and bursty senders such as a Bluetooth proxy stall on the IDF default.
             add_idf_sdkconfig_option("CONFIG_LWIP_TCP_SND_BUF_DEFAULT", 65534)
-            add_idf_sdkconfig_option("CONFIG_LWIP_TCP_WND_DEFAULT", 65534)
+            add_idf_sdkconfig_option("CONFIG_LWIP_TCP_WND_DEFAULT", tcp_window)
             add_idf_sdkconfig_option("CONFIG_LWIP_TCP_RECVMBOX_SIZE", 64)
-            add_idf_sdkconfig_option("CONFIG_LWIP_TCPIP_RECVMBOX_SIZE", 64)
+            add_idf_sdkconfig_option("CONFIG_LWIP_TCPIP_RECVMBOX_SIZE", tcpip_mailbox)
 
     # After the high performance block so an explicit size wins over the
     # bundle's 65534 (last write wins in the sdkconfig store).
diff --git a/esphome/components/wifi/__init__.py b/esphome/components/wifi/__init__.py
index c9616a6c29..1ba8946841 100644
--- a/esphome/components/wifi/__init__.py
+++ b/esphome/components/wifi/__init__.py
@@ -771,7 +771,7 @@ async def to_code(config):
                 "Applying high-performance WiFi settings (PSRAM guaranteed): 512 RX buffers, 32 TX buffers"
             )
             # PSRAM is guaranteed - use aggressive settings
-            # Higher maximum values are allowed because CONFIG_LWIP_WND_SCALE is set to true in networking component
+            # Higher maximum values are allowed because CONFIG_LWIP_WND_SCALE may be set to true in networking component
             # Based on https://github.com/espressif/esp-adf/issues/297#issuecomment-783811702
 
             # Large dynamic RX buffers (requires PSRAM)
diff --git a/tests/component_tests/network/__init__.py b/tests/component_tests/network/__init__.py
index e69de29bb2..b4ed442ff8 100644
--- a/tests/component_tests/network/__init__.py
+++ b/tests/component_tests/network/__init__.py
@@ -0,0 +1,11 @@
+"""Shared helpers for the network component tests."""
+
+from esphome.components.esp32.const import KEY_ESP32, KEY_SDKCONFIG_OPTIONS
+from esphome.core import CORE
+
+
+def sdkconfig_option(name: str) -> int | bool | None:
+    """Return a generated sdkconfig value, or None when unset or not ESP32."""
+    if KEY_ESP32 not in CORE.data:
+        return None
+    return CORE.data[KEY_ESP32][KEY_SDKCONFIG_OPTIONS].get(name)
diff --git a/tests/component_tests/network/config/high_perf_ethernet_no_psram.yaml b/tests/component_tests/network/config/high_perf_ethernet_no_psram.yaml
new file mode 100644
index 0000000000..31858c3fc5
--- /dev/null
+++ b/tests/component_tests/network/config/high_perf_ethernet_no_psram.yaml
@@ -0,0 +1,20 @@
+esphome:
+  name: test
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+ethernet:
+  type: LAN8720
+  mdc_pin: 23
+  mdio_pin: 32
+  clk:
+    pin: 0
+    mode: CLK_EXT_IN
+  phy_addr: 0
+  power_pin: 33
+
+network:
+  enable_high_performance: true
diff --git a/tests/component_tests/network/config/high_perf_ethernet_psram.yaml b/tests/component_tests/network/config/high_perf_ethernet_psram.yaml
new file mode 100644
index 0000000000..3407fd5ffe
--- /dev/null
+++ b/tests/component_tests/network/config/high_perf_ethernet_psram.yaml
@@ -0,0 +1,23 @@
+esphome:
+  name: test
+
+esp32:
+  variant: esp32s3
+  framework:
+    type: esp-idf
+
+psram:
+  mode: octal
+  ignore_not_found: false
+
+ethernet:
+  type: W5500
+  clk_pin: GPIO12
+  mosi_pin: GPIO11
+  miso_pin: GPIO13
+  cs_pin: GPIO10
+  interrupt_pin: GPIO14
+  reset_pin: GPIO9
+
+network:
+  enable_high_performance: true
diff --git a/tests/component_tests/network/config/high_perf_wifi_ethernet_psram.yaml b/tests/component_tests/network/config/high_perf_wifi_ethernet_psram.yaml
new file mode 100644
index 0000000000..b9b49c825d
--- /dev/null
+++ b/tests/component_tests/network/config/high_perf_wifi_ethernet_psram.yaml
@@ -0,0 +1,30 @@
+esphome:
+  name: test
+
+esp32:
+  variant: esp32s3
+  framework:
+    type: esp-idf
+
+psram:
+  mode: octal
+  ignore_not_found: false
+
+wifi:
+  ssid: "test_ssid"
+  password: "test_password"
+
+ethernet:
+  type: W5500
+  clk_pin: GPIO12
+  mosi_pin: GPIO11
+  miso_pin: GPIO13
+  cs_pin: GPIO10
+  interrupt_pin: GPIO14
+  reset_pin: GPIO9
+
+network:
+  priority:
+    - wifi
+    - ethernet
+  enable_high_performance: true
diff --git a/tests/component_tests/network/config/high_perf_wifi_no_psram.yaml b/tests/component_tests/network/config/high_perf_wifi_no_psram.yaml
new file mode 100644
index 0000000000..c24e4b6253
--- /dev/null
+++ b/tests/component_tests/network/config/high_perf_wifi_no_psram.yaml
@@ -0,0 +1,14 @@
+esphome:
+  name: test
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: "test_ssid"
+  password: "test_password"
+
+network:
+  enable_high_performance: true
diff --git a/tests/component_tests/network/config/high_perf_wifi_psram.yaml b/tests/component_tests/network/config/high_perf_wifi_psram.yaml
new file mode 100644
index 0000000000..efdad282a4
--- /dev/null
+++ b/tests/component_tests/network/config/high_perf_wifi_psram.yaml
@@ -0,0 +1,18 @@
+esphome:
+  name: test
+
+esp32:
+  variant: esp32s3
+  framework:
+    type: esp-idf
+
+psram:
+  mode: octal
+  ignore_not_found: false
+
+wifi:
+  ssid: "test_ssid"
+  password: "test_password"
+
+network:
+  enable_high_performance: true
diff --git a/tests/component_tests/network/test_high_performance.py b/tests/component_tests/network/test_high_performance.py
new file mode 100644
index 0000000000..c291806ac4
--- /dev/null
+++ b/tests/component_tests/network/test_high_performance.py
@@ -0,0 +1,54 @@
+"""Tests for the ``network: enable_high_performance:`` lwip tier selection.
+
+Ethernet drivers keep received frames in internal RAM, so an ethernet-only
+build must keep lwip off the PSRAM tier even when PSRAM is guaranteed.
+"""
+
+from collections.abc import Callable
+from pathlib import Path
+
+import pytest
+
+from esphome.components.network import require_high_performance_networking
+from tests.component_tests.network import sdkconfig_option
+
+
+@pytest.mark.parametrize(
+    (
+        "fixture",
+        "window",
+        "tcp_mailbox",
+        "tcpip_mailbox",
+        "window_scale",
+        "wifi_rx_buffers",
+    ),
+    [
+        ("high_perf_wifi_psram.yaml", 512000, 512, 512, True, 512),
+        ("high_perf_wifi_no_psram.yaml", 65534, 64, 64, None, 64),
+        # dual builds keep wifi's sizes; the ethernet component moves frames to PSRAM
+        ("high_perf_wifi_ethernet_psram.yaml", 512000, 512, 512, True, 512),
+        ("high_perf_ethernet_no_psram.yaml", 16384, 64, 32, None, None),
+        # ethernet only with PSRAM guaranteed: the cell the guard exists for
+        ("high_perf_ethernet_psram.yaml", 16384, 64, 32, None, None),
+    ],
+)
+def test_lwip_tier(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+    fixture: str,
+    window: int,
+    tcp_mailbox: int,
+    tcpip_mailbox: int,
+    window_scale: bool | None,
+    wifi_rx_buffers: int | None,
+) -> None:
+    # The wifi component only reacts to a component request, so request it the
+    # way sendspin does; the config key alone decides the lwip tier.
+    require_high_performance_networking()
+    generate_main(component_config_path(fixture))
+    assert sdkconfig_option("CONFIG_LWIP_TCP_WND_DEFAULT") == window
+    assert sdkconfig_option("CONFIG_LWIP_TCP_RECVMBOX_SIZE") == tcp_mailbox
+    assert sdkconfig_option("CONFIG_LWIP_TCPIP_RECVMBOX_SIZE") == tcpip_mailbox
+    assert sdkconfig_option("CONFIG_LWIP_WND_SCALE") is window_scale
+    # Wifi RX buffers really go to PSRAM, so the wifi tier is never downgraded
+    assert sdkconfig_option("CONFIG_ESP_WIFI_DYNAMIC_RX_BUFFER_NUM") == wifi_rx_buffers
diff --git a/tests/component_tests/network/test_priority.py b/tests/component_tests/network/test_priority.py
index 041b358dda..57e412ea19 100644
--- a/tests/component_tests/network/test_priority.py
+++ b/tests/component_tests/network/test_priority.py
@@ -19,6 +19,7 @@ from esphome.components.network import (
 from esphome.const import CONF_PRIORITY, PlatformFramework
 from esphome.core import CORE
 import esphome.final_validate as fv
+from tests.component_tests.network import sdkconfig_option
 from tests.component_tests.types import SetCoreConfigCallable
 
 
@@ -217,13 +218,7 @@ def test_no_primary_interface_define_without_priority(
 
 
 def _dns_per_default_netif_option() -> bool | None:
-    from esphome.components.esp32.const import KEY_ESP32, KEY_SDKCONFIG_OPTIONS
-
-    if KEY_ESP32 not in CORE.data:  # non-ESP32 configs have no sdkconfig at all
-        return None
-    return CORE.data[KEY_ESP32][KEY_SDKCONFIG_OPTIONS].get(
-        "CONFIG_ESP_NETIF_SET_DNS_PER_DEFAULT_NETIF"
-    )
+    return sdkconfig_option("CONFIG_ESP_NETIF_SET_DNS_PER_DEFAULT_NETIF")
 
 
 @pytest.mark.parametrize(
diff --git a/tests/component_tests/network/test_tcp_send_buffer.py b/tests/component_tests/network/test_tcp_send_buffer.py
index 6498921243..bf68c7c11c 100644
--- a/tests/component_tests/network/test_tcp_send_buffer.py
+++ b/tests/component_tests/network/test_tcp_send_buffer.py
@@ -14,32 +14,24 @@ import pytest
 from voluptuous import Invalid
 
 from esphome import config_validation as cv
-from esphome.components.esp32.const import (
-    KEY_SDKCONFIG_OPTIONS,
-    KEY_VARIANT,
-    VARIANT_ESP32,
-)
+from esphome.components.esp32.const import KEY_VARIANT, VARIANT_ESP32
 from esphome.components.network import (
     CONF_TCP_SEND_BUFFER,
     CONFIG_SCHEMA,
     TCP_SEND_BUFFER_MAX,
     TCP_SEND_BUFFER_MIN,
 )
-from esphome.const import KEY_ESP32, KEY_FRAMEWORK_VERSION, PlatformFramework
-from esphome.core import CORE
+from esphome.const import KEY_FRAMEWORK_VERSION, PlatformFramework
+from tests.component_tests.network import sdkconfig_option
 from tests.component_tests.types import SetCoreConfigCallable
 
 
-def _sdkconfig_option(name: str) -> int | None:
-    return CORE.data[KEY_ESP32][KEY_SDKCONFIG_OPTIONS].get(name)
-
-
 def test_tcp_send_buffer_sets_sdkconfig(
     generate_main: Callable[[str | Path], str],
     component_config_path: Callable[[str], Path],
 ) -> None:
     generate_main(component_config_path("tcp_send_buffer.yaml"))
-    assert _sdkconfig_option("CONFIG_LWIP_TCP_SND_BUF_DEFAULT") == 32000
+    assert sdkconfig_option("CONFIG_LWIP_TCP_SND_BUF_DEFAULT") == 32000
 
 
 def test_tcp_send_buffer_overrides_high_performance(
@@ -48,7 +40,7 @@ def test_tcp_send_buffer_overrides_high_performance(
 ) -> None:
     """An explicit size wins over the high performance bundle's 65534."""
     generate_main(component_config_path("tcp_send_buffer_high_perf.yaml"))
-    assert _sdkconfig_option("CONFIG_LWIP_TCP_SND_BUF_DEFAULT") == 16384
+    assert sdkconfig_option("CONFIG_LWIP_TCP_SND_BUF_DEFAULT") == 16384
 
 
 @pytest.mark.parametrize("value", [TCP_SEND_BUFFER_MIN, TCP_SEND_BUFFER_MAX])
diff --git a/tests/components/network/test-priority.esp32-idf.yaml b/tests/components/network/test-priority.esp32-idf.yaml
index baa821a234..ccafd74543 100644
--- a/tests/components/network/test-priority.esp32-idf.yaml
+++ b/tests/components/network/test-priority.esp32-idf.yaml
@@ -3,6 +3,11 @@
 # it must actually compile (not just validate) to guard the reconciler wiring.
 # WiFi is listed first so the build also exercises the wifi-primary branch in
 # network/util.cpp (the ethernet-primary branch matches the legacy order).
+# PSRAM guaranteed plus high performance networking: a dual build keeps wifi's
+# PSRAM tier, so this compiles the sdkconfig a wifi + ethernet audio device gets.
+psram:
+  ignore_not_found: false
+
 wifi:
   ssid: MySSID
   password: password1
@@ -21,3 +26,4 @@ network:
   priority:
     - wifi
     - ethernet
+  enable_high_performance: true