diff --git a/test/common/README.md b/test/common/README.md
index 1f47baf7a8593f..2b8f852a3b74dd 100644
--- a/test/common/README.md
+++ b/test/common/README.md
@@ -438,10 +438,9 @@ The `cpu-prof` module provides utilities related to CPU profiling tests.
 
 ### env
 
-* Default: { ...process.env, FIB, NODE_DEBUG_NATIVE: 'INSPECTOR_PROFILER' }
+* Default: { ...process.env, NODE_DEBUG_NATIVE: 'INSPECTOR_PROFILER' }
 
-Environment variables used in profiled processes. FIB will be set to `40` on
-Windows and `30` elsewhere.
+Environment variables used in profiled processes.
 
 ### getCpuProfiles(dir)
 
diff --git a/test/common/cpu-prof.js b/test/common/cpu-prof.js
index 8e8bd42275b7d8..ae81eefd45c307 100644
--- a/test/common/cpu-prof.js
+++ b/test/common/cpu-prof.js
@@ -2,7 +2,7 @@
 
 'use strict';
 
-const common = require('./');
+require('./');
 const fs = require('fs');
 const path = require('path');
 const assert = require('assert');
@@ -34,23 +34,12 @@ function verifyFrames(output, file, suffix) {
   assert.notDeepStrictEqual(frames, []);
 }
 
-let FIB = 30;
-// This is based on emperial values - in the CI, on Windows the program
-// tend to finish too fast then we won't be able to see the profiled script
-// in the samples, so we need to bump the values a bit. On slower platforms
-// like the Pis it could take more time to complete, we need to use a
-// smaller value so the test would not time out.
-if (common.isWindows) {
-  FIB = 40;
-}
-
 // We need to set --cpu-interval to a smaller value to make sure we can
 // find our workload in the samples. 50us should be a small enough sampling
 // interval for this.
 const kCpuProfInterval = 50;
 const env = {
   ...process.env,
-  FIB,
   NODE_DEBUG_NATIVE: 'INSPECTOR_PROFILER'
 };
 
diff --git a/test/fixtures/workload/fibonacci.js b/test/fixtures/workload/fibonacci.js
index 899006daa5af37..0326914d048203 100644
--- a/test/fixtures/workload/fibonacci.js
+++ b/test/fixtures/workload/fibonacci.js
@@ -4,5 +4,12 @@ function fib(n) {
   return fib(n - 1) + fib(n - 2);
 }
 
-const n = parseInt(process.env.FIB) || 35;
+// This is based on emperial values - in the CI, on Windows the program
+// tend to finish too fast then we won't be able to see the profiled script
+// in the samples, so we need to bump the values a bit. On slower platforms
+// like the Pis it could take more time to complete, we need to use a
+// smaller value so the test would not time out.
+const FIB = process.platform === 'win32' ? 40 : 30;
+
+const n = parseInt(process.env.FIB) || FIB;
 process.stdout.write(`${fib(n)}\n`);