diff --git a/ggml-common.h b/ggml-common.h
index 66d984b5a..409fcf29e 100644
--- a/ggml-common.h
+++ b/ggml-common.h
@@ -1023,70 +1023,70 @@ GGML_TABLE_BEGIN(uint32_t, iq3s_grid, 512)
 GGML_TABLE_END()
 
 GGML_TABLE_BEGIN(uint32_t, i2s_i8s, 256)
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00010000, 0x01010000, 0x00010000, 0xff010000,
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
-0x00000100, 0x01000100, 0x00000100, 0xff000100,
-0x00010100, 0x01010100, 0x00010100, 0xff010100,
-0x00000100, 0x01000100, 0x00000100, 0xff000100,
-0x00ff0100, 0x01ff0100, 0x00ff0100, 0xffff0100,
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00010000, 0x01010000, 0x00010000, 0xff010000,
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
-0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
-0x0001ff00, 0x0101ff00, 0x0001ff00, 0xff01ff00,
-0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
-0x00ffff00, 0x01ffff00, 0x00ffff00, 0xffffff00,
-0x00000001, 0x01000001, 0x00000001, 0xff000001,
-0x00010001, 0x01010001, 0x00010001, 0xff010001,
-0x00000001, 0x01000001, 0x00000001, 0xff000001,
-0x00ff0001, 0x01ff0001, 0x00ff0001, 0xffff0001,
-0x00000101, 0x01000101, 0x00000101, 0xff000101,
-0x00010101, 0x01010101, 0x00010101, 0xff010101,
-0x00000101, 0x01000101, 0x00000101, 0xff000101,
-0x00ff0101, 0x01ff0101, 0x00ff0101, 0xffff0101,
-0x00000001, 0x01000001, 0x00000001, 0xff000001,
-0x00010001, 0x01010001, 0x00010001, 0xff010001,
-0x00000001, 0x01000001, 0x00000001, 0xff000001,
-0x00ff0001, 0x01ff0001, 0x00ff0001, 0xffff0001,
-0x0000ff01, 0x0100ff01, 0x0000ff01, 0xff00ff01,
-0x0001ff01, 0x0101ff01, 0x0001ff01, 0xff01ff01,
-0x0000ff01, 0x0100ff01, 0x0000ff01, 0xff00ff01,
-0x00ffff01, 0x01ffff01, 0x00ffff01, 0xffffff01,
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00010000, 0x01010000, 0x00010000, 0xff010000,
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
-0x00000100, 0x01000100, 0x00000100, 0xff000100,
-0x00010100, 0x01010100, 0x00010100, 0xff010100,
-0x00000100, 0x01000100, 0x00000100, 0xff000100,
-0x00ff0100, 0x01ff0100, 0x00ff0100, 0xffff0100,
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00010000, 0x01010000, 0x00010000, 0xff010000,
-0x00000000, 0x01000000, 0x00000000, 0xff000000,
-0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
-0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
-0x0001ff00, 0x0101ff00, 0x0001ff00, 0xff01ff00,
-0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
-0x00ffff00, 0x01ffff00, 0x00ffff00, 0xffffff00,
-0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
-0x000100ff, 0x010100ff, 0x000100ff, 0xff0100ff,
-0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
-0x00ff00ff, 0x01ff00ff, 0x00ff00ff, 0xffff00ff,
-0x000001ff, 0x010001ff, 0x000001ff, 0xff0001ff,
-0x000101ff, 0x010101ff, 0x000101ff, 0xff0101ff,
-0x000001ff, 0x010001ff, 0x000001ff, 0xff0001ff,
-0x00ff01ff, 0x01ff01ff, 0x00ff01ff, 0xffff01ff,
-0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
-0x000100ff, 0x010100ff, 0x000100ff, 0xff0100ff,
-0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
-0x00ff00ff, 0x01ff00ff, 0x00ff00ff, 0xffff00ff,
-0x0000ffff, 0x0100ffff, 0x0000ffff, 0xff00ffff,
-0x0001ffff, 0x0101ffff, 0x0001ffff, 0xff01ffff,
-0x0000ffff, 0x0100ffff, 0x0000ffff, 0xff00ffff,
-0x00ffffff, 0x01ffffff, 0x00ffffff, 0xffffffff,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00010000, 0x01010000, 0x00010000, 0xff010000,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
+    0x00000100, 0x01000100, 0x00000100, 0xff000100,
+    0x00010100, 0x01010100, 0x00010100, 0xff010100,
+    0x00000100, 0x01000100, 0x00000100, 0xff000100,
+    0x00ff0100, 0x01ff0100, 0x00ff0100, 0xffff0100,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00010000, 0x01010000, 0x00010000, 0xff010000,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
+    0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
+    0x0001ff00, 0x0101ff00, 0x0001ff00, 0xff01ff00,
+    0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
+    0x00ffff00, 0x01ffff00, 0x00ffff00, 0xffffff00,
+    0x00000001, 0x01000001, 0x00000001, 0xff000001,
+    0x00010001, 0x01010001, 0x00010001, 0xff010001,
+    0x00000001, 0x01000001, 0x00000001, 0xff000001,
+    0x00ff0001, 0x01ff0001, 0x00ff0001, 0xffff0001,
+    0x00000101, 0x01000101, 0x00000101, 0xff000101,
+    0x00010101, 0x01010101, 0x00010101, 0xff010101,
+    0x00000101, 0x01000101, 0x00000101, 0xff000101,
+    0x00ff0101, 0x01ff0101, 0x00ff0101, 0xffff0101,
+    0x00000001, 0x01000001, 0x00000001, 0xff000001,
+    0x00010001, 0x01010001, 0x00010001, 0xff010001,
+    0x00000001, 0x01000001, 0x00000001, 0xff000001,
+    0x00ff0001, 0x01ff0001, 0x00ff0001, 0xffff0001,
+    0x0000ff01, 0x0100ff01, 0x0000ff01, 0xff00ff01,
+    0x0001ff01, 0x0101ff01, 0x0001ff01, 0xff01ff01,
+    0x0000ff01, 0x0100ff01, 0x0000ff01, 0xff00ff01,
+    0x00ffff01, 0x01ffff01, 0x00ffff01, 0xffffff01,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00010000, 0x01010000, 0x00010000, 0xff010000,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
+    0x00000100, 0x01000100, 0x00000100, 0xff000100,
+    0x00010100, 0x01010100, 0x00010100, 0xff010100,
+    0x00000100, 0x01000100, 0x00000100, 0xff000100,
+    0x00ff0100, 0x01ff0100, 0x00ff0100, 0xffff0100,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00010000, 0x01010000, 0x00010000, 0xff010000,
+    0x00000000, 0x01000000, 0x00000000, 0xff000000,
+    0x00ff0000, 0x01ff0000, 0x00ff0000, 0xffff0000,
+    0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
+    0x0001ff00, 0x0101ff00, 0x0001ff00, 0xff01ff00,
+    0x0000ff00, 0x0100ff00, 0x0000ff00, 0xff00ff00,
+    0x00ffff00, 0x01ffff00, 0x00ffff00, 0xffffff00,
+    0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
+    0x000100ff, 0x010100ff, 0x000100ff, 0xff0100ff,
+    0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
+    0x00ff00ff, 0x01ff00ff, 0x00ff00ff, 0xffff00ff,
+    0x000001ff, 0x010001ff, 0x000001ff, 0xff0001ff,
+    0x000101ff, 0x010101ff, 0x000101ff, 0xff0101ff,
+    0x000001ff, 0x010001ff, 0x000001ff, 0xff0001ff,
+    0x00ff01ff, 0x01ff01ff, 0x00ff01ff, 0xffff01ff,
+    0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
+    0x000100ff, 0x010100ff, 0x000100ff, 0xff0100ff,
+    0x000000ff, 0x010000ff, 0x000000ff, 0xff0000ff,
+    0x00ff00ff, 0x01ff00ff, 0x00ff00ff, 0xffff00ff,
+    0x0000ffff, 0x0100ffff, 0x0000ffff, 0xff00ffff,
+    0x0001ffff, 0x0101ffff, 0x0001ffff, 0xff01ffff,
+    0x0000ffff, 0x0100ffff, 0x0000ffff, 0xff00ffff,
+    0x00ffffff, 0x01ffffff, 0x00ffffff, 0xffffffff,
 GGML_TABLE_END()
 
 #define NGRID_IQ1S 2048
diff --git a/ggml-quants.c b/ggml-quants.c
index 665e381a3..4b5209279 100644
--- a/ggml-quants.c
+++ b/ggml-quants.c
@@ -3799,60 +3799,61 @@ void ggml_vec_dot_i2_i8_s(int n, float * restrict s, size_t bs, const void * res
     UNUSED(by);
     UNUSED(nrc);
 
-// TODO
-// #if defined(__AVX2__)
-//     __m256i accu = _mm256_setzero_si256();
+#if defined(__AVX2__)
+    __m256i accu = _mm256_setzero_si256();
 
-//     for (int i=0; i<n/32; i++) {
-//         const int8_t* w0 = (const int8_t *)(i2s_i8s + x[i*8 + 0]);
-//         const int8_t* w1 = (const int8_t *)(i2s_i8s + x[i*8 + 1]);
-//         const int8_t* w2 = (const int8_t *)(i2s_i8s + x[i*8 + 2]);
-//         const int8_t* w3 = (const int8_t *)(i2s_i8s + x[i*8 + 3]);
-//         const int8_t* w4 = (const int8_t *)(i2s_i8s + x[i*8 + 4]);
-//         const int8_t* w5 = (const int8_t *)(i2s_i8s + x[i*8 + 5]);
-//         const int8_t* w6 = (const int8_t *)(i2s_i8s + x[i*8 + 6]);
-//         const int8_t* w7 = (const int8_t *)(i2s_i8s + x[i*8 + 7]);
+    // max group_size is 128 (2^8)
+    // limited by 8640 to 2 (8640 % (2 * 32) == 0)
+    int group_num = 2;
 
-//         __m256i xq8 = _mm256_set_epi8(
-//             w0[0], w0[1], w0[2], w0[3],
-//             w1[0], w1[1], w1[2], w1[3],
-//             w2[0], w2[1], w2[2], w2[3],
-//             w3[0], w3[1], w3[2], w3[3],
-//             w4[0], w4[1], w4[2], w4[3],
-//             w5[0], w5[1], w5[2], w5[3],
-//             w6[0], w6[1], w6[2], w6[3],
-//             w7[0], w7[1], w7[2], w7[3]
-//         );
+    for (int i=0; i < n / (group_num * 32); i++){
+        __m256i laccu = _mm256_setzero_si256();
+        __m256i haccu = _mm256_setzero_si256();
 
-//         __m256i yq8 = _mm256_loadu_si256((const __m256i*)(y + i*32));
+        for (int j=0; j < group_num; j++) {
+            __m256i xq8 = _mm256_set_epi32(
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 7]],
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 6]],
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 5]],
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 4]],
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 3]],
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 2]],
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 1]],
+                (int)i2s_i8s[x[i * group_num * 8 + j * 8 + 0]]
+            );
 
-//         __m128i hxq8 = _mm256_castsi256_si128(xq8);
-//         __m128i lxq8 = _mm256_extractf128_si256(xq8, 1);
-//         __m128i hyq8 = _mm256_castsi256_si128(yq8);
-//         __m128i lyq8 = _mm256_extractf128_si256(yq8, 1);
+            __m256i yq8 = _mm256_loadu_si256((const __m256i*)(y + i * group_num * 32 + j * 32));
 
-//         __m256i hxq16 = _mm256_cvtepi8_epi16(hxq8);
-//         __m256i lxq16 = _mm256_cvtepi8_epi16(lxq8);
-//         __m256i hyq16 = _mm256_cvtepi8_epi16(hyq8);
-//         __m256i lyq16 = _mm256_cvtepi8_epi16(lyq8);
+            __m128i hxq8 = _mm256_castsi256_si128(xq8);
+            __m128i lxq8 = _mm256_extractf128_si256(xq8, 1);
+            __m128i hyq8 = _mm256_castsi256_si128(yq8);
+            __m128i lyq8 = _mm256_extractf128_si256(yq8, 1);
 
-//         __m256i hzq16 = _mm256_sign_epi16(hyq16, hxq16);
-//         __m256i lzq16 = _mm256_sign_epi16(lyq16, lxq16);
+            __m256i hxq16 = _mm256_cvtepi8_epi16(hxq8);
+            __m256i lxq16 = _mm256_cvtepi8_epi16(lxq8);
+            __m256i hyq16 = _mm256_cvtepi8_epi16(hyq8);
+            __m256i lyq16 = _mm256_cvtepi8_epi16(lyq8);
 
-//         __m256i hhzq32 = _mm256_cvtepi16_epi32(_mm256_castsi256_si128(hzq16));
-//         __m256i hlzq32 = _mm256_cvtepi16_epi32(_mm256_extractf128_si256(hzq16, 1));
-//         __m256i llzq32 = _mm256_cvtepi16_epi32(_mm256_castsi256_si128(lzq16));
-//         __m256i lhzq32 = _mm256_cvtepi16_epi32(_mm256_extractf128_si256(lzq16, 1));
+            __m256i hzq16 = _mm256_sign_epi16(hyq16, hxq16);
+            __m256i lzq16 = _mm256_sign_epi16(lyq16, lxq16);
 
-//         accu = _mm256_add_epi32(accu, hhzq32);
-//         accu = _mm256_add_epi32(accu, hlzq32);
-//         accu = _mm256_add_epi32(accu, llzq32);
-//         accu = _mm256_add_epi32(accu, lhzq32);
-//     }
+            haccu = _mm256_add_epi16(haccu, hzq16);
+            laccu = _mm256_add_epi16(laccu, lzq16);
+        }
 
-//     int sumi = hsum_i32_8(accu);
-//     *s = (float)sumi;
-// #else
+        __m256i hhzq32 = _mm256_cvtepi16_epi32(_mm256_castsi256_si128(haccu));
+        __m256i hlzq32 = _mm256_cvtepi16_epi32(_mm256_extractf128_si256(haccu, 1));
+        __m256i llzq32 = _mm256_cvtepi16_epi32(_mm256_castsi256_si128(laccu));
+        __m256i lhzq32 = _mm256_cvtepi16_epi32(_mm256_extractf128_si256(laccu, 1));
+
+        accu = _mm256_add_epi32(accu, hhzq32);
+        accu = _mm256_add_epi32(accu, hlzq32);
+        accu = _mm256_add_epi32(accu, llzq32);
+        accu = _mm256_add_epi32(accu, lhzq32);
+    }
+    int sumi = hsum_i32_8(accu);
+    *s = (float)sumi;
+#else
 
     int sumi = 0;
 
@@ -3864,7 +3865,7 @@ void ggml_vec_dot_i2_i8_s(int n, float * restrict s, size_t bs, const void * res
         sumi += (int)y[i*4+3] * weight[3];
     }
     *s = (float)sumi;
-// #endif
+#endif
 }
 
 void ggml_vec_dot_q4_0_q8_0(int n, float * restrict s, size_t bs, const void * restrict vx, size_t bx, const void * restrict vy, size_t by, int nrc) {
diff --git a/llama.cpp b/llama.cpp
index 5ebdeb024..16ae07dd3 100644
--- a/llama.cpp
+++ b/llama.cpp
@@ -11702,7 +11702,6 @@ struct llm_build_context {
 
                 cur = ggml_mul_mat(ctx0, model.layers[il].ffn_down, cur);
                 cb(cur, "ffn_down", il);
-    
             }
             cur = ggml_add(ctx0, cur, ffn_inp);
             cb(cur, "l_out", il);
@@ -11723,7 +11722,6 @@ struct llm_build_context {
         cb(cur, "result_output", -1);
 
         ggml_build_forward_expand(gf, cur);
-
         return gf;
     }