diff --git a/ggml-metal.metal b/ggml-metal.metal
index 5070561fb..66ed14120 100644
--- a/ggml-metal.metal
+++ b/ggml-metal.metal
@@ -1757,29 +1757,34 @@ void dequantize_f16(device const half4x4 * src, short il, thread type4x4 & reg)
 
 template <typename type4x4>
 void dequantize_q4_0(device const block_q4_0 *xb, short il, thread type4x4 & reg) {
+
     device const uint16_t * qs = ((device const uint16_t *)xb + 1);
-    const half d = il ? (xb->d / 16.h) : xb->d;
-    const half m = il ? ( -8.h * 16.h) : -8.h;
+    const float d1 = il ? (xb->d / 16.h) : xb->d;
+    const float d2 = d1 / 256.f;
+    const float md = -8.h * xb->d;
     const ushort mask0 = il ? 0x00F0 : 0x000F;
-    const ushort mask1 = il ? 0xF000 : 0x0F00;
+    const ushort mask1 = mask0 << 8;
 
     for (int i=0;i<8;i++) {
-        reg[i/2][2*(i%2)]   = (((qs[i] & mask0)     ) + m) * d;
-        reg[i/2][2*(i%2)+1] = (((qs[i] & mask1) >> 8) + m) * d;
+        reg[i/2][2*(i%2)+0] = d1 * (qs[i] & mask0) + md;
+        reg[i/2][2*(i%2)+1] = d2 * (qs[i] & mask1) + md;
     }
+
 }
 
 template <typename type4x4>
 void dequantize_q4_1(device const block_q4_1 *xb, short il, thread type4x4 & reg) {
+
     device const uint16_t * qs = ((device const uint16_t *)xb + 2);
-    const half d = il ? (xb->d / 16.h) : xb->d;
-    const half m = xb->m;
+    const float d1 = il ? (xb->d / 16.h) : xb->d;
+    const float d2 = d1 / 256.f;
+    const float  m = xb->m;
     const ushort mask0 = il ? 0x00F0 : 0x000F;
-    const ushort mask1 = il ? 0xF000 : 0x0F00;
+    const ushort mask1 = mask0 << 8;
 
     for (int i=0;i<8;i++) {
-        reg[i/2][2*(i%2)]   = (((qs[i] & mask0)     ) * d) + m;
-        reg[i/2][2*(i%2)+1] = (((qs[i] & mask1) >> 8) * d) + m;
+        reg[i/2][2*(i%2)+0] = ((qs[i] & mask0) * d1) + m;
+        reg[i/2][2*(i%2)+1] = ((qs[i] & mask1) * d2) + m;
     }
 }
 
@@ -1815,7 +1820,7 @@ void dequantize_q2_K(device const block_q2_K *xb, short il, thread type4x4 & reg
 
 template <typename type4x4>
 void dequantize_q3_K(device const block_q3_K *xb, short il, thread type4x4 & reg) {
-    const float d_all = (float)(xb->d);
+    const half d_all = xb->d;
     device const uint8_t * q = (device const uint8_t *)xb->qs;
     device const uint8_t * h = (device const uint8_t *)xb->hmask;
     device const int8_t * scales = (device const int8_t *)xb->scales;
@@ -1828,17 +1833,20 @@ void dequantize_q3_K(device const block_q3_K *xb, short il, thread type4x4 & reg
                                  ((il/4)>0 ? 12  : 3);
     uint16_t kmask2 = il/8 ? 0xF0 : 0x0F;
     uint16_t scale_2 = scales[il%8], scale_1 = scales[8 + il%4];
-    int16_t  dl_int = (il/4)&1 ? (scale_2&kmask2) | ((scale_1&kmask1) << 2) : \
-                                 (scale_2&kmask2) | ((scale_1&kmask1) << 4);
-    float dl = il<8 ? d_all * (dl_int - 32.f) : d_all * (dl_int / 16.f - 32.f);
+    int16_t  dl_int = (il/4)&1 ? (scale_2&kmask2) | ((scale_1&kmask1) << 2)
+                               : (scale_2&kmask2) | ((scale_1&kmask1) << 4);
+    half dl = il<8 ? d_all * (dl_int - 32.h) : d_all * (dl_int / 16.h - 32.h);
+    const half ml = 4.h * dl;
 
-    il = (il/2)%4;
-    float   coef = il>1 ? (il>2 ? 1/64.h : 1/16.h) : (il>0 ? 1/4.h : 1.h);
-    uint8_t mask = il>1 ? (il>2 ? 192    : 48)     : (il>0 ? 12    : 3);
+    il = (il/2) & 3;
+    const half    coef = il>1 ? (il>2 ? 1/64.h : 1/16.h) : (il>0 ? 1/4.h : 1.h);
+    const uint8_t mask = il>1 ? (il>2 ? 192    : 48)     : (il>0 ? 12    : 3);
+    dl *= coef;
 
     for (int i = 0; i < 16; ++i) {
-        reg[i/4][i%4] = coef * dl * ((q[i] & mask) - ((h[i] & m) ? 0 : 4.f/coef));
+        reg[i/4][i%4] = dl * (q[i] & mask) - (h[i] & m ? 0 : ml);
     }
+
 #else
     float    kcoef = il&1 ? 1.f/16.f : 1.f;
     uint16_t kmask = il&1 ? 0xF0     : 0x0F;
@@ -1852,31 +1860,37 @@ void dequantize_q3_K(device const block_q3_K *xb, short il, thread type4x4 & reg
 #endif
 }
 
+static inline uchar2 get_scale_min_k4_just2(int j, int k, device const uchar * q) {
+    return j < 4 ? uchar2{uchar(q[j+0+k] & 63), uchar(q[j+4+k] & 63)}
+                 : uchar2{uchar((q[j+4+k] & 0xF) | ((q[j-4+k] & 0xc0) >> 2)), uchar((q[j+4+k] >> 4) | ((q[j-0+k] & 0xc0) >> 2))};
+}
+
 template <typename type4x4>
 void dequantize_q4_K(device const block_q4_K *xb, short il, thread type4x4 & reg) {
-    device const uint8_t * q = xb->qs;
+    device const uchar * q = xb->qs;
 
 #if QK_K == 256
-    const float d = (float)(xb->d);
-    const float min = (float)(xb->dmin);
     short is = (il/4) * 2;
     q = q + (il/4) * 32 + 16 * (il&1);
-    il = il%4;
-    const uchar4 sc = get_scale_min_k4(is, xb->scales);
-    const float dl = il<2 ? d * sc[0]   : d * sc[2]/16.h;
-    const float ml = il<2 ? min * sc[1] : min * sc[3];
+    il = il & 3;
+    const uchar2 sc = get_scale_min_k4_just2(is, il/2, xb->scales);
+    const half d   = il < 2 ? xb->d : xb->d / 16.h;
+    const half min = xb->dmin;
+    const half dl = d * sc[0];
+    const half ml = min * sc[1];
 #else
     q = q + 16 * (il&1);
     device const uint8_t * s = xb->scales;
     device const half2 * dh = (device const half2 *)xb->d;
     const float2 d = (float2)dh[0];
     const float dl = il<2 ? d[0] * (s[0]&0xF) : d[0] * (s[1]&0xF)/16.h;
-    const float ml = il<2 ? d[1] * (s[0]>>4)  : d[1 ]* (s[1]>>4);
+    const float ml = il<2 ? d[1] * (s[0]>>4)  : d[1] * (s[1]>>4);
 #endif
     const ushort mask = il<2 ? 0x0F : 0xF0;
     for (int i = 0; i < 16; ++i) {
         reg[i/4][i%4] = dl * (q[i] & mask) - ml;
     }
+
 }
 
 template <typename type4x4>
@@ -1885,19 +1899,19 @@ void dequantize_q5_K(device const block_q5_K *xb, short il, thread type4x4 & reg
     device const uint8_t * qh = xb->qh;
 
 #if QK_K == 256
-    const float d = (float)(xb->d);
-    const float min = (float)(xb->dmin);
     short is = (il/4) * 2;
     q  = q + 32 * (il/4) + 16 * (il&1);
     qh = qh + 16 * (il&1);
     uint8_t ul = 1 << (il/2);
-    il = il%4;
-    const uchar4 sc = get_scale_min_k4(is, xb->scales);
-    const float dl = il<2 ? d * sc[0]   : d * sc[2]/16.h;
-    const float ml = il<2 ? min * sc[1] : min * sc[3];
+    il = il & 3;
+    const uchar2 sc = get_scale_min_k4_just2(is, il/2, xb->scales);
+    const half d = il < 2 ? xb->d : xb->d / 16.h;
+    const half min = xb->dmin;
+    const half dl = d * sc[0];
+    const half ml = min * sc[1];
 
-    const ushort mask   = il<2 ? 0x0F : 0xF0;
-    const float  qh_val = il<2 ? 16.f : 256.f;
+    const ushort mask = il<2 ? 0x0F : 0xF0;
+    const half qh_val = il<2 ? 16.h : 256.h;
     for (int i = 0; i < 16; ++i) {
         reg[i/4][i%4] = dl * ((q[i] & mask) + (qh[i] & ul ? qh_val : 0)) - ml;
     }
@@ -1916,7 +1930,7 @@ void dequantize_q5_K(device const block_q5_K *xb, short il, thread type4x4 & reg
 
 template <typename type4x4>
 void dequantize_q6_K(device const block_q6_K *xb, short il, thread type4x4 & reg) {
-    const float d_all = (float)(xb->d);
+    const half d_all = xb->d;
     device const uint8_t * ql = (device const uint8_t *)xb->ql;
     device const uint8_t * qh = (device const uint8_t *)xb->qh;
     device const int8_t * scales = (device const int8_t *)xb->scales;
@@ -1924,19 +1938,21 @@ void dequantize_q6_K(device const block_q6_K *xb, short il, thread type4x4 & reg
 #if QK_K == 256
     ql = ql + 64*(il/8) + 32*((il/2)&1) + 16*(il&1);
     qh = qh + 32*(il/8) + 16*(il&1);
-    float sc = scales[(il%2) + 2 * ((il/2))];
-    il = (il/2)%4;
+    half sc = scales[(il%2) + 2 * ((il/2))];
+    il = (il/2) & 3;
 #else
     ql = ql + 16 * (il&1);
-    float sc = scales[il];
+    half sc = scales[il];
 #endif
+    const uint16_t  kmask1 = il>1 ? (il>2 ? 192 : 48) : (il>0 ? 12 : 3);
+    const uint16_t  kmask2 = il>1 ? 0xF0              : 0x0F;
+    const half        coef = il>1 ? 1.f/16.h          : 1.h;
+    const half ml = d_all * sc * 32.h;
+    const half dl = d_all * sc * coef;
     for (int i = 0; i < 16; ++i) {
-        uint16_t  kmask1 = il>1 ? (il>2 ? 192 : 48) : (il>0 ? 12 : 3);
-        uint16_t  kmask2 = il>1 ? 0xF0              : 0x0F;
-        const float coef = il>1 ? 1.f/16.f          : 1.f;
-        float q = il&1 ? ((ql[i]&kmask2)|((qh[i]&kmask1)<<2)) - 32.f/coef : \
-                         ((ql[i]&kmask2)|((qh[i]&kmask1)<<4)) - 32.f/coef;
-        reg[i/4][i%4] = d_all * sc * q * coef;
+        const half q = il&1 ? ((ql[i] & kmask2) | ((qh[i] & kmask1) << 2))
+                            : ((ql[i] & kmask2) | ((qh[i] & kmask1) << 4));
+        reg[i/4][i%4] = dl * q - ml;
     }
 }