diff --git a/README.md b/README.md
index c443790..4dcc0d6 100644
--- a/README.md
+++ b/README.md
@@ -50,6 +50,7 @@ pppwn --interface en0 --fw 1100 --stage1 "stage1.bin" --stage2 "stage2.bin" --ti
 - `-bs` `--buffer-size`: PCAP buffer size in bytes, less than 100 indicates default value (usually 2MB) (default: `0`)
 - `-a` `--auto-retry`: automatically retry when fails or timeout
 - `-nw` `--no-wait-padi`: don't wait one more [PADI](https://en.wikipedia.org/wiki/Point-to-Point_Protocol_over_Ethernet#Client_to_server:_Initiation_(PADI)) before starting the exploit
+- `-rs` `--real-sleep`: use CPU for more precise sleep time (Only used when execution speed is too slow)
 - `--web`: use the web interface
 - `--url`: the url of the web interface (default: `0.0.0.0:7796`)
 
diff --git a/include/exploit.h b/include/exploit.h
index 69a55b1..3019f0d 100644
--- a/include/exploit.h
+++ b/include/exploit.h
@@ -90,6 +90,8 @@ class Exploit {
 
     void setAutoRetry(bool retry);
 
+    void setRealSleep(bool sleep);
+
     void closeInterface();
 
     void updateSourceMac(uint64_t value);
@@ -140,6 +142,7 @@ class Exploit {
     std::vector<uint8_t> stage2_bin{};
     bool auto_retry{};
     bool wait_padi{};
+    bool real_sleep{};
     int timeout{};
     int wait_after_pin{1};
     int groom_delay{4};
diff --git a/src/exploit.cpp b/src/exploit.cpp
index 986e668..300d1c1 100644
--- a/src/exploit.cpp
+++ b/src/exploit.cpp
@@ -82,6 +82,12 @@ struct Cookie {
 #define startBlockingCapture(cb) if(dev->startCaptureBlockingMode(cb, nullptr, this->timeout) != 1) { return running ? RETURN_FAIL : RETURN_STOP; }
 #define startBlockingCaptureWithCookie(cb, cookie) if(dev->startCaptureBlockingMode(cb, cookie, this->timeout) != 1) { return running ? RETURN_FAIL : RETURN_STOP; }
 
+static void cpuSleep(int ms) {
+    auto start = std::chrono::high_resolution_clock::now();
+    auto end = start + std::chrono::milliseconds(ms);
+    while (std::chrono::high_resolution_clock::now() < end) {}
+}
+
 int Exploit::setFirmwareVersion(FirmwareVersion version) {
     switch (version) {
         case FirmwareVersion::FIRMWARE_700_702:
@@ -160,6 +166,10 @@ void Exploit::setAutoRetry(bool value) {
     this->auto_retry = value;
 }
 
+void Exploit::setRealSleep(bool sleep) {
+    this->real_sleep = sleep;
+}
+
 void Exploit::setTimeout(int value) {
     this->timeout = value;
 }
@@ -735,7 +745,7 @@ int Exploit::stage0() {
             dev->sendPacket(&packet);
         }
 
-        if (i % groom_delay == 0) pcpp::multiPlatformMSleep(1);
+        if (i % groom_delay == 0) real_sleep ? cpuSleep(1) : pcpp::multiPlatformMSleep(1);
     }
     TIME_END_PERIOD();
     std::cout << "\r[+] Heap grooming...done" << std::endl;
@@ -759,7 +769,7 @@ int Exploit::stage1() {
         auto &&echoReply = PacketBuilder::lcpEchoReply(etherLayer->getDestMac(), etherLayer->getSourceMac(),
                                                        pppLayer->getPPPoEHeader()->sessionId,
                                                        pppLayer->getLayerPayload()[1], // id
-                                                       *(uint32_t *) &pppLayer->getLayerPayload()[4]); // magic number
+                                                       *(uint32_t * ) & pppLayer->getLayerPayload()[4]); // magic number
         device->sendPacket(&echoReply);
     }, nullptr);
 
@@ -777,7 +787,7 @@ int Exploit::stage1() {
                           << (100 * i / PIN_NUM) << "%" << std::flush;
             }
             dev->sendPacket(&packet);
-            pcpp::multiPlatformMSleep(1);
+            real_sleep ? cpuSleep(1) : pcpp::multiPlatformMSleep(1);
             CHECK_RUNNING();
         }
         TIME_END_PERIOD();
@@ -864,7 +874,7 @@ int Exploit::stage1() {
             dev->sendPacket(&packet);
         }
 
-        if (i % groom_delay == 0) pcpp::multiPlatformMSleep(1);
+        if (i % groom_delay == 0) real_sleep ? cpuSleep(1) : pcpp::multiPlatformMSleep(1);
     }
     TIME_END_PERIOD();
 
@@ -894,7 +904,7 @@ int Exploit::stage2() {
                 if (option[0] != 1) return false; // type 1 is ICMPv6NDOptSrcLLAddr
                 if (option[1] > 1) {
                     auto *self = (Exploit *) cookie;
-                    self->pppoe_softc_list = *(uint64_t *) (option + 3);
+                    self->pppoe_softc_list = *(uint64_t * )(option + 3);
                     return true; // length > 1
                 }
                 return false;
diff --git a/src/main.cpp b/src/main.cpp
index 48b0698..63dadaf 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -125,6 +125,7 @@ int main(int argc, char *argv[]) {
     bool retry = false;
     bool no_wait_padi = false;
     bool web_page = false;
+    bool real_sleep = false;
 
     auto cli = (
             ("network interface" % required("-i", "--interface") & value("interface", interface), \
@@ -141,6 +142,8 @@ int main(int argc, char *argv[]) {
             option("-bs", "--buffer-size") & integer("bytes", buffer_size), \
             "automatically retry when fails or timeout" % option("-a", "--auto-retry").set(retry), \
             "don't wait one more PADI before starting" % option("-nw", "--no-wait-padi").set(no_wait_padi), \
+            "Use CPU for more precise sleep time (Only used when execution speed is too slow)" %
+            option("-rs", "--real-sleep").set(real_sleep), \
             "start a web page" % option("--web").set(web_page), \
             "url" % option("--url") & value("url", web_url)
             ) | \
@@ -163,6 +166,7 @@ int main(int argc, char *argv[]) {
     std::cout << "[+] args: interface=" << interface << " fw=" << fw << " stage1=" << stage1 << " stage2=" << stage2
               << " timeout=" << timeout << " wait-after-pin=" << wait_after_pin << " groom-delay=" << groom_delay
               << " auto-retry=" << (retry ? "on" : "off") << " no-wait-padi=" << (no_wait_padi ? "on" : "off")
+              << " real_sleep=" << (real_sleep ? "on" : "off")
               << std::endl;
 
     signal(SIGPIPE, SIG_IGN);
@@ -182,6 +186,7 @@ int main(int argc, char *argv[]) {
     exploit->setGroomDelay(groom_delay);
     exploit->setWaitAfterPin(wait_after_pin);
     exploit->setAutoRetry(retry);
+    exploit->setRealSleep(real_sleep);
 
     if (web_page) {
         web = std::make_shared<WebPage>(exploit);