diff --git a/src/anlogicCable.hpp b/src/anlogicCable.hpp
index e0ab806..3ccd3b4 100644
--- a/src/anlogicCable.hpp
+++ b/src/anlogicCable.hpp
@@ -35,8 +35,6 @@ class AnlogicCable : public JtagInterface {
 	virtual ~AnlogicCable();
 
 	int setClkFreq(uint32_t clkHZ) override;
-	int setClkFreq(uint32_t clkHZ, char use_divide_by_5) override {
-		(void)use_divide_by_5; return setClkFreq(clkHZ);}
 
 	/* TMS */
 	int writeTMS(uint8_t *tms, int len, bool flush_buffer) override;
diff --git a/src/dirtyJtag.hpp b/src/dirtyJtag.hpp
index 62a79af..515958f 100644
--- a/src/dirtyJtag.hpp
+++ b/src/dirtyJtag.hpp
@@ -35,8 +35,6 @@ class DirtyJtag : public JtagInterface {
 	virtual ~DirtyJtag();
 
 	int setClkFreq(uint32_t clkHZ) override;
-	int setClkFreq(uint32_t clkHZ, char use_divide_by_5) override {
-		(void)use_divide_by_5; return setClkFreq(clkHZ);}
 
 	/* TMS */
 	int writeTMS(uint8_t *tms, int len, bool flush_buffer) override;
diff --git a/src/ftdiJtagBitbang.hpp b/src/ftdiJtagBitbang.hpp
index d067584..ca413e7 100644
--- a/src/ftdiJtagBitbang.hpp
+++ b/src/ftdiJtagBitbang.hpp
@@ -41,8 +41,6 @@ class FtdiJtagBitBang : public JtagInterface, private FTDIpp_MPSSE {
 	virtual ~FtdiJtagBitBang();
 
 	int setClkFreq(uint32_t clkHZ) override;
-	int setClkFreq(uint32_t clkHZ, char use_divide_by_5) override {
-		return FTDIpp_MPSSE::setClkFreq(clkHZ, use_divide_by_5);}
 
 	/* TMS */
 	int writeTMS(uint8_t *tms, int len, bool flush_buffer) override;
diff --git a/src/ftdiJtagMPSSE.hpp b/src/ftdiJtagMPSSE.hpp
index d6285b3..5b3282d 100644
--- a/src/ftdiJtagMPSSE.hpp
+++ b/src/ftdiJtagMPSSE.hpp
@@ -41,8 +41,6 @@ class FtdiJtagMPSSE : public JtagInterface, private FTDIpp_MPSSE {
 	int setClkFreq(uint32_t clkHZ) override {
 		return FTDIpp_MPSSE::setClkFreq(clkHZ);
 	}
-	int setClkFreq(uint32_t clkHZ, char use_divide_by_5) override {
-		return FTDIpp_MPSSE::setClkFreq(clkHZ, use_divide_by_5);}
 
 	/* TMS */
 	int writeTMS(uint8_t *tms, int len, bool flush_buffer) override;
diff --git a/src/ftdipp_mpsse.cpp b/src/ftdipp_mpsse.cpp
index 48625e8..3fa0880 100644
--- a/src/ftdipp_mpsse.cpp
+++ b/src/ftdipp_mpsse.cpp
@@ -169,7 +169,7 @@ int FTDIpp_MPSSE::init(unsigned char latency, unsigned char bitmask_mode,
 		unsigned char buf1[5];
 		ftdi_read_data(_ftdi, buf1, 5);
 
-		if (setClkFreq(_clkHZ, 0) < 0)
+		if (setClkFreq(_clkHZ) < 0)
 			return -1;
 
 		int to_wr = 3;
@@ -194,29 +194,31 @@ int FTDIpp_MPSSE::init(unsigned char latency, unsigned char bitmask_mode,
 
 int FTDIpp_MPSSE::setClkFreq(uint32_t clkHZ)
 {
-	return setClkFreq(clkHZ, 0);
-}
-
-int FTDIpp_MPSSE::setClkFreq(uint32_t clkHZ, char use_divide_by_5)
-{
-	_clkHZ = clkHZ;
-
 	int ret;
+	bool use_divide_by_5;
 	uint8_t buffer[4] = { TCK_DIVISOR, 0x00, 0x00};
 	uint32_t base_freq;
-	uint32_t real_freq = 0;
+	float real_freq = 0;
 	uint16_t presc;
 
+	_clkHZ = clkHZ;
+
 	/* FT2232C has no divide by 5 instruction
 	 * and default freq is 12MHz
 	 */
 	if (_ftdi->type != TYPE_2232C) {
 		base_freq = 60000000;
-		if (use_divide_by_5) {
+		/* use full speed only when freq > 6MHz
+		 * => more freq resolution using
+		 * 2^16 to describe 0 -> 6MHz
+		 */
+		if (clkHZ > 6000000) {
+			use_divide_by_5 = false;
+			mpsse_store(DIS_DIV_5);
+		} else {
+			use_divide_by_5 = true;
 			base_freq /= 5;
 			mpsse_store(EN_DIV_5);
-		} else {
-			mpsse_store(DIS_DIV_5);
 		}
 	} else {
 		base_freq = 12000000;
@@ -240,10 +242,33 @@ int FTDIpp_MPSSE::setClkFreq(uint32_t clkHZ, char use_divide_by_5)
 	if (real_freq > _clkHZ)
 		presc ++;
 	real_freq = base_freq / ((1+presc)*2);
-	printInfo("Jtag frequency : requested " + std::to_string(clkHZ) +
-			"Hz -> real " + std::to_string(real_freq) + "Hz");
-	display("presc : %d input freq : %d requested freq : %d real freq : %d\n",
+
+	/* just to have a better display */
+	string clkHZ_str(10, ' ');
+	string real_freq_str(10, ' ');
+	if (clkHZ >= 1e6)
+		snprintf(&clkHZ_str[0], 9, "%2.2fMHz", clkHZ / 1e6);
+	else if (clkHZ >= 1e3)
+		snprintf(&clkHZ_str[0], 10, "%3.2fKHz", clkHZ / 1e3);
+	else
+		snprintf(&clkHZ_str[0], 10, "%3d.00Hz", clkHZ);
+	if (real_freq >= 1e6)
+		snprintf(&real_freq_str[0], 9, "%2.2fMHz", real_freq / 1e6);
+	else if (real_freq >= 1e3)
+		snprintf(&real_freq_str[0], 10, "%3.2fKHz", real_freq / 1e3);
+	else
+		snprintf(&real_freq_str[0], 10, "%3.2fHz", real_freq);
+
+
+	printInfo("Jtag frequency : requested " + clkHZ_str +
+			" -> real " + real_freq_str);
+	display("presc : %d input freq : %d requested freq : %d real freq : %f\n",
 			presc, base_freq, _clkHZ, real_freq);
+
+	/*printf("base freq %d div by 5 %c presc %d\n", base_freq, (use_divide_by_5)?'1':'0',
+			presc); */
+
+
 	buffer[1] = presc & 0xff;
 	buffer[2] = (presc >> 8) & 0xff;
 
diff --git a/src/ftdipp_mpsse.hpp b/src/ftdipp_mpsse.hpp
index 3a48ee8..532dce4 100644
--- a/src/ftdipp_mpsse.hpp
+++ b/src/ftdipp_mpsse.hpp
@@ -22,7 +22,6 @@ class FTDIpp_MPSSE {
 		int init(unsigned char latency, unsigned char bitmask_mode,
 			unsigned char mode);
 		int setClkFreq(uint32_t clkHZ);
-		int setClkFreq(uint32_t clkHZ, char use_divide_by_5);
 
 		int vid() {return _vid;}
 		int pid() {return _pid;}
diff --git a/src/gowin.cpp b/src/gowin.cpp
index 3b1bfb9..70bdfe8 100644
--- a/src/gowin.cpp
+++ b/src/gowin.cpp
@@ -87,7 +87,7 @@ Gowin::Gowin(Jtag *jtag, const string filename, Device::prog_type_t prg_type,
 			throw std::runtime_error("incompatible file format");
 		}
 	}
-	_jtag->setClkFreq(2500000, 0);
+	_jtag->setClkFreq(2500000);
 
 	/* erase and program flash differ for GW1N1 */
 	if (idCode() == 0x0900281B)
diff --git a/src/jtag.hpp b/src/jtag.hpp
index 9f6cb7e..57d7210 100644
--- a/src/jtag.hpp
+++ b/src/jtag.hpp
@@ -35,8 +35,6 @@ class Jtag {
 
 	/* maybe to update */
 	int setClkFreq(uint32_t clkHZ) { return _jtag->setClkFreq(clkHZ);}
-	int setClkFreq(uint32_t clkHZ, char use_divide_by_5) {
-		return _jtag->setClkFreq(clkHZ, use_divide_by_5);}
 
 	int detectChain(std::vector<int> &devices, int max_dev);
 
diff --git a/src/jtagInterface.hpp b/src/jtagInterface.hpp
index d9ec6a1..ff93d1f 100644
--- a/src/jtagInterface.hpp
+++ b/src/jtagInterface.hpp
@@ -33,7 +33,6 @@ class JtagInterface {
 	virtual ~JtagInterface() {}
 
 	virtual int setClkFreq(uint32_t clkHZ) = 0;
-	virtual int setClkFreq(uint32_t clkHZ, char use_divide_by_5) = 0;
 
 	/*!
 	 * \brief flush TMS internal buffer (ie. transmit to converter)
diff --git a/src/usbBlaster.hpp b/src/usbBlaster.hpp
index 4a5a30c..a5283b6 100644
--- a/src/usbBlaster.hpp
+++ b/src/usbBlaster.hpp
@@ -39,9 +39,6 @@ class UsbBlaster : public JtagInterface {
 	virtual ~UsbBlaster();
 
 	int setClkFreq(uint32_t clkHZ) override;
-	int setClkFreq(uint32_t clkHZ, char use_divide_by_5) override {
-		(void)clkHZ; (void) use_divide_by_5;
-		return 1;}
 
 	/*!
 	 * \brief drive TMS to move in JTAG state machine