diff --git a/compute-pressure/compute_pressure_basic.https.any.js b/compute-pressure/compute_pressure_basic.https.any.js
index 28322ced729af6d..15d572bd8eed7dd 100644
--- a/compute-pressure/compute_pressure_basic.https.any.js
+++ b/compute-pressure/compute_pressure_basic.https.any.js
@@ -21,7 +21,7 @@ pressure_test(async (t, mockPressureService) => {
     t.add_cleanup(() => observer.disconnect());
     observer.observe('cpu');
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
   assert_true(changes.length === 1);
   assert_equals(changes[0].state, 'critical');
@@ -37,7 +37,7 @@ pressure_test((t, mockPressureService) => {
   const promise = observer.observe('cpu');
   observer.unobserve('cpu');
   mockPressureService.setPressureUpdate('cpu', 'critical');
-  mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+  mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
 
   return promise_rejects_dom(t, 'AbortError', promise);
 }, 'Removing observer before observe() resolves works');
@@ -57,7 +57,7 @@ pressure_test(async (t, mockPressureService) => {
   await Promise.all(observePromises);
 
   mockPressureService.setPressureUpdate('cpu', 'critical');
-  mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+  mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
 
   return Promise.all(callbackPromises);
 }, 'Calling observe() multiple times works');
@@ -72,7 +72,7 @@ pressure_test(async (t, mockPressureService) => {
     t.add_cleanup(() => observer1.disconnect());
     observer1.observe('cpu');
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
   assert_true(observer1_changes.length === 1);
   assert_equals(observer1_changes[0][0].source, 'cpu');
diff --git a/compute-pressure/compute_pressure_detached_iframe.https.html b/compute-pressure/compute_pressure_detached_iframe.https.html
index 5511a147048d610..6123521248cb7f6 100644
--- a/compute-pressure/compute_pressure_detached_iframe.https.html
+++ b/compute-pressure/compute_pressure_detached_iframe.https.html
@@ -69,7 +69,7 @@
     t.add_cleanup(() => observer.disconnect());
     observer.observe('cpu').catch(reject);
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
   assert_equals(changes[0].state, 'critical');
 }, 'Detaching frame while PressureObserver.observe() settles');
@@ -84,7 +84,7 @@
 
   await observer.observe('cpu');
   mockPressureService.setPressureUpdate('cpu', 'critical');
-  mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+  mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
 
   iframe.remove();
 
diff --git a/compute-pressure/compute_pressure_disconnect.https.any.js b/compute-pressure/compute_pressure_disconnect.https.any.js
index 1d188fad8b8e1cd..f8bc3fb357811a3 100644
--- a/compute-pressure/compute_pressure_disconnect.https.any.js
+++ b/compute-pressure/compute_pressure_disconnect.https.any.js
@@ -31,7 +31,7 @@ pressure_test(async (t, mockPressureService) => {
     t.add_cleanup(() => observer2.disconnect());
     observer2.observe('cpu').catch(reject);
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
 
   assert_equals(
diff --git a/compute-pressure/compute_pressure_disconnect_idempotent.https.any.js b/compute-pressure/compute_pressure_disconnect_idempotent.https.any.js
index 74d37bd6e5cc75c..3c9a6688a42fb8e 100644
--- a/compute-pressure/compute_pressure_disconnect_idempotent.https.any.js
+++ b/compute-pressure/compute_pressure_disconnect_idempotent.https.any.js
@@ -25,7 +25,7 @@ pressure_test(async (t, mockPressureService) => {
     t.add_cleanup(() => observer2.disconnect());
     observer2.observe('cpu').catch(reject);
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
 
   assert_equals(
diff --git a/compute-pressure/compute_pressure_disconnect_immediately.https.any.js b/compute-pressure/compute_pressure_disconnect_immediately.https.any.js
index 9b545fbe1c33bc4..86963e242aba383 100644
--- a/compute-pressure/compute_pressure_disconnect_immediately.https.any.js
+++ b/compute-pressure/compute_pressure_disconnect_immediately.https.any.js
@@ -24,7 +24,7 @@ pressure_test(async (t, mockPressureService) => {
     t.add_cleanup(() => observer2.disconnect());
     observer2.observe('cpu').catch(reject);
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
 
   assert_equals(
@@ -55,7 +55,7 @@ pressure_test(async (t, mockPressureService) => {
     observer1.disconnect();
     await promise_rejects_dom(t, 'AbortError', promise);
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
 
   assert_equals(
diff --git a/compute-pressure/compute_pressure_duplicate_updates.https.any.js b/compute-pressure/compute_pressure_duplicate_updates.https.any.js
index dde92932dd14e7d..04c5df5e5767c16 100644
--- a/compute-pressure/compute_pressure_duplicate_updates.https.any.js
+++ b/compute-pressure/compute_pressure_duplicate_updates.https.any.js
@@ -12,11 +12,11 @@ pressure_test(async (t, mockPressureService) => {
       observer_changes.push(changes);
       if (++n === 2)
         resolve(observer_changes);
-    }, {sampleRate: 5.0});
+    }, {sampleInterval: 200});
     observer.observe('cpu');
     const updatesDelivered = mockPressureService.updatesDelivered();
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval*/ 200);
     // Deliver 2 updates.
     await t.step_wait(
         () => mockPressureService.updatesDelivered() >= (updatesDelivered + 2),
diff --git a/compute-pressure/compute_pressure_multiple.https.any.js b/compute-pressure/compute_pressure_multiple.https.any.js
index c8cef5beca0cba5..8c50cc4b3df27e9 100644
--- a/compute-pressure/compute_pressure_multiple.https.any.js
+++ b/compute-pressure/compute_pressure_multiple.https.any.js
@@ -24,7 +24,7 @@ pressure_test(async (t, mockPressureService) => {
   });
 
   mockPressureService.setPressureUpdate('cpu', 'critical');
-  mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+  mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
 
   const [changes1, changes2, changes3] =
       await Promise.all([changes1_promise, changes2_promise, changes3_promise]);
diff --git a/compute-pressure/compute_pressure_observe_idempotent.https.any.js b/compute-pressure/compute_pressure_observe_idempotent.https.any.js
index 5dc3804b2f7ea21..9fcbb49814b6c0a 100644
--- a/compute-pressure/compute_pressure_observe_idempotent.https.any.js
+++ b/compute-pressure/compute_pressure_observe_idempotent.https.any.js
@@ -12,7 +12,7 @@ pressure_test(async (t, mockPressureService) => {
     observer.observe('cpu').catch(reject);
     observer.observe('cpu').catch(reject);
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
 
   assert_equals(update[0].state, 'critical');
diff --git a/compute-pressure/compute_pressure_options.https.any.js b/compute-pressure/compute_pressure_options.https.any.js
index 69999819d962fbf..d0760ef6224db75 100644
--- a/compute-pressure/compute_pressure_options.https.any.js
+++ b/compute-pressure/compute_pressure_options.https.any.js
@@ -3,23 +3,24 @@
 'use strict';
 
 test(t => {
-  assert_throws_js(RangeError, () => {
-    new PressureObserver(() => {}, {sampleRate: 0});
-  });
-}, 'PressureObserver constructor requires a non-zero sampleRate');
+  const observer = new PressureObserver(() => {}, {sampleInterval: 0});
+  assert_equals(typeof observer, 'object');
+}, 'PressureObserver constructor doesnt throw error for sampleInterval value 0');
+
 
 test(t => {
-  assert_throws_js(RangeError, () => {
-    new PressureObserver(() => {}, {sampleRate: -2});
+  assert_throws_js(TypeError, () => {
+    new PressureObserver(() => {}, {sampleInterval: -2});
   });
-}, 'PressureObserver constructor requires a positive sampleRate');
+}, 'PressureObserver constructor requires a positive sampleInterval');
 
 test(t => {
-  const observer = new PressureObserver(() => {}, {sampleRate: 0.5});
-  assert_equals(typeof observer, 'object');
-}, 'PressureObserver constructor doesnt throw error on positive sampleRate');
+  assert_throws_js(TypeError, () => {
+    new PressureObserver(() => {}, {sampleInterval: 2 ** 32});
+  });
+}, 'PressureObserver constructor requires a sampleInterval in unsigned long range');
 
 test(t => {
   const observer = new PressureObserver(() => {}, {});
   assert_equals(typeof observer, 'object');
-}, 'PressureObserver constructor succeeds on empty sampleRate');
+}, 'PressureObserver constructor succeeds on empty sampleInterval');
diff --git a/compute-pressure/compute_pressure_rate_obfuscation_mitigation_not_triggered.https.window.js b/compute-pressure/compute_pressure_rate_obfuscation_mitigation_not_triggered.https.window.js
index cb1aa432ce61244..e348a8ea08886b6 100644
--- a/compute-pressure/compute_pressure_rate_obfuscation_mitigation_not_triggered.https.window.js
+++ b/compute-pressure/compute_pressure_rate_obfuscation_mitigation_not_triggered.https.window.js
@@ -6,7 +6,7 @@
 'use strict';
 
 pressure_test(async (t, mockPressureService) => {
-  const sampleRateInHz = 10;
+  const sampleIntervalInMs = 100;
   const readings = ['nominal', 'fair', 'serious', 'critical'];
   // Normative values for rate obfuscation parameters.
   // https://w3c.github.io/compute-pressure/#rate-obfuscation-normative-parameters.
@@ -17,10 +17,10 @@ pressure_test(async (t, mockPressureService) => {
     const observerChanges = [];
     const observer = new PressureObserver(changes => {
       observerChanges.push(changes);
-    }, {sampleRate: sampleRateInHz});
+    }, {sampleInterval: sampleIntervalInMs});
 
     observer.observe('cpu');
-    mockPressureService.startPlatformCollector(sampleRateInHz);
+    mockPressureService.startPlatformCollector(sampleIntervalInMs);
     let i = 0;
     // mockPressureService.updatesDelivered() does not necessarily match
     // pressureChanges.length, as system load and browser optimizations can
diff --git a/compute-pressure/compute_pressure_rate_obfuscation_mitigation_triggered.https.window.js b/compute-pressure/compute_pressure_rate_obfuscation_mitigation_triggered.https.window.js
index 11dcc3c70aa1518..ebe33bc8bf712d9 100644
--- a/compute-pressure/compute_pressure_rate_obfuscation_mitigation_triggered.https.window.js
+++ b/compute-pressure/compute_pressure_rate_obfuscation_mitigation_triggered.https.window.js
@@ -6,7 +6,7 @@
 'use strict';
 
 pressure_test(async (t, mockPressureService) => {
-  const sampleRateInHz = 25;
+  const sampleIntervalInMs = 40;
   const readings = ['nominal', 'fair', 'serious', 'critical'];
   // Normative values for rate obfuscation parameters.
   // https://w3c.github.io/compute-pressure/#rate-obfuscation-normative-parameters.
@@ -31,10 +31,10 @@ pressure_test(async (t, mockPressureService) => {
         }
       }
       observerChanges.push(changes);
-    }, {sampleRate: sampleRateInHz});
+    }, {sampleInterval: sampleIntervalInMs});
 
     observer.observe('cpu');
-    mockPressureService.startPlatformCollector(sampleRateInHz);
+    mockPressureService.startPlatformCollector(sampleIntervalInMs);
     let i = 0;
     // mockPressureService.updatesDelivered() does not necessarily match
     // pressureChanges.length, as system load and browser optimizations can
diff --git a/compute-pressure/compute_pressure_take_records.https.any.js b/compute-pressure/compute_pressure_take_records.https.any.js
index d93c9b5c886f9d5..55660b228be2245 100644
--- a/compute-pressure/compute_pressure_take_records.https.any.js
+++ b/compute-pressure/compute_pressure_take_records.https.any.js
@@ -20,7 +20,7 @@ pressure_test(async (t, mockPressureService) => {
 
     observer.observe('cpu');
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
   assert_equals(changes[0].state, 'critical');
 
diff --git a/compute-pressure/compute_pressure_timestamp.https.any.js b/compute-pressure/compute_pressure_timestamp.https.any.js
index f283caa6baebbe5..09caeb34789df24 100644
--- a/compute-pressure/compute_pressure_timestamp.https.any.js
+++ b/compute-pressure/compute_pressure_timestamp.https.any.js
@@ -7,15 +7,15 @@
 pressure_test(async (t, mockPressureService) => {
   const readings = ['nominal', 'fair', 'serious', 'critical'];
 
-  const sampleRate = 4.0;
+  const sampleInterval = 250;
   const pressureChanges = await new Promise(async resolve => {
     const observerChanges = [];
     const observer = new PressureObserver(changes => {
       observerChanges.push(changes);
-    }, {sampleRate});
+    }, {sampleInterval});
     observer.observe('cpu');
 
-    mockPressureService.startPlatformCollector(sampleRate * 2);
+    mockPressureService.startPlatformCollector(sampleInterval / 2);
     let i = 0;
     // mockPressureService.updatesDelivered() does not necessarily match
     // pressureChanges.length, as system load and browser optimizations can
@@ -34,27 +34,24 @@ pressure_test(async (t, mockPressureService) => {
 
   assert_equals(pressureChanges.length, 4);
   assert_greater_than_equal(
-      pressureChanges[1][0].time - pressureChanges[0][0].time,
-      (1 / sampleRate * 1000));
+      pressureChanges[1][0].time - pressureChanges[0][0].time, sampleInterval);
   assert_greater_than_equal(
-      pressureChanges[2][0].time - pressureChanges[1][0].time,
-      (1 / sampleRate * 1000));
+      pressureChanges[2][0].time - pressureChanges[1][0].time, sampleInterval);
   assert_greater_than_equal(
-      pressureChanges[3][0].time - pressureChanges[2][0].time,
-      (1 / sampleRate * 1000));
+      pressureChanges[3][0].time - pressureChanges[2][0].time, sampleInterval);
 }, 'Faster collector: Timestamp difference between two changes should be higher or equal to the observer sample rate');
 
 pressure_test(async (t, mockPressureService) => {
   const pressureChanges = [];
-  const sampleRate = 1.0;
+  const sampleInterval = 1000;
   const observer = new PressureObserver(changes => {
     pressureChanges.push(changes);
-  }, {sampleRate});
+  }, {sampleInterval});
 
   await new Promise(async resolve => {
     observer.observe('cpu');
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(sampleRate);
+    mockPressureService.startPlatformCollector(sampleInterval);
     await t.step_wait(() => pressureChanges.length == 1);
     observer.disconnect();
     resolve();
@@ -63,7 +60,7 @@ pressure_test(async (t, mockPressureService) => {
   await new Promise(async resolve => {
     observer.observe('cpu');
     mockPressureService.setPressureUpdate('cpu', 'serious');
-    mockPressureService.startPlatformCollector(sampleRate * 4);
+    mockPressureService.startPlatformCollector(sampleInterval / 4);
     await t.step_wait(() => pressureChanges.length == 2);
     observer.disconnect();
     resolve();
@@ -74,6 +71,5 @@ pressure_test(async (t, mockPressureService) => {
   // should be deleted. So the second PressureRecord is not discarded even
   // though the time interval does not meet the requirement.
   assert_less_than(
-      pressureChanges[1][0].time - pressureChanges[0][0].time,
-      (1 / sampleRate * 1000));
+      pressureChanges[1][0].time - pressureChanges[0][0].time, sampleInterval);
 }, 'disconnect() should update [[LastRecordMap]]');
diff --git a/compute-pressure/compute_pressure_update_toJSON.https.any.js b/compute-pressure/compute_pressure_update_toJSON.https.any.js
index 0024d6975490619..7f726698d61dd30 100644
--- a/compute-pressure/compute_pressure_update_toJSON.https.any.js
+++ b/compute-pressure/compute_pressure_update_toJSON.https.any.js
@@ -7,7 +7,7 @@ pressure_test(async (t, mockPressureService) => {
     const observer = new PressureObserver(resolve);
     observer.observe('cpu');
     mockPressureService.setPressureUpdate('cpu', 'critical');
-    mockPressureService.startPlatformCollector(/*sampleRate=*/ 5.0);
+    mockPressureService.startPlatformCollector(/*sampleInterval=*/ 200);
   });
   assert_true(changes.length === 1);
   const json = changes[0].toJSON();
diff --git a/compute-pressure/idlharness.https.any.js b/compute-pressure/idlharness.https.any.js
index e8289962324eee3..48ab5615b03fbe4 100644
--- a/compute-pressure/idlharness.https.any.js
+++ b/compute-pressure/idlharness.https.any.js
@@ -11,5 +11,5 @@ idl_test(['compute-pressure'], ['dom', 'html'], async idl_array => {
     PressureObserver: ['observer'],
   });
 
-  self.observer = new PressureObserver(() => {}, {sampleRate: 1.0});
+  self.observer = new PressureObserver(() => {}, {sampleInterval: 1000});
 });
diff --git a/resources/chromium/mock-pressure-service.js b/resources/chromium/mock-pressure-service.js
index 02d10f856ae458a..bd0e32c5673888f 100644
--- a/resources/chromium/mock-pressure-service.js
+++ b/resources/chromium/mock-pressure-service.js
@@ -58,8 +58,8 @@ class MockPressureService {
     return {status: this.pressureStatus_};
   }
 
-  startPlatformCollector(sampleRate) {
-    if (sampleRate === 0)
+  startPlatformCollector(sampleInterval) {
+    if (sampleInterval === 0)
       return;
 
     if (this.pressureServiceReadingTimerId_ != null)
@@ -80,7 +80,6 @@ class MockPressureService {
     // |epochDeltaInMs| equals to base::Time::kTimeTToMicrosecondsOffset.
     const epochDeltaInMs = unixEpoch - windowsEpoch;
 
-    const timeout = (1 / sampleRate) * 1000;
     this.pressureServiceReadingTimerId_ = self.setInterval(() => {
       if (this.pressureUpdate_ === null || this.observers_.length === 0)
         return;
@@ -90,7 +89,7 @@ class MockPressureService {
       for (let observer of this.observers_)
         observer.onPressureUpdated(this.pressureUpdate_);
       this.updatesDelivered_++;
-    }, timeout);
+    }, sampleInterval);
   }
 
   stopPlatformCollector() {