diff --git a/bestla/bestla/kernel_avx2.h b/bestla/bestla/kernel_avx2.h
index de577ae64..34610d90a 100644
--- a/bestla/bestla/kernel_avx2.h
+++ b/bestla/bestla/kernel_avx2.h
@@ -80,6 +80,21 @@ static inline void convert_s4_s8_16_sse(int8_t* dstptr, int8_t* srcptr) {
   _mm_storeu_si128(reinterpret_cast<__m128i*>(dstptr), dst0);
 }
 
+template <BTLA_DTYPE S4_T>
+static inline void convert_s4_s8_32_avx(int8_t* dstptr, int8_t* srcptr) {
+  const __m128i xmm = _mm_loadu_si128((const __m128i*)srcptr);
+  const __m256i decmp_v = _mm256_inserti128_si256(_mm256_castsi128_si256(xmm), _mm_srli_epi16(xmm, 4), 0x01);
+  const __m256i lowMask = _mm256_set1_epi8(0xF);
+  auto dst0 = _mm256_and_si256(decmp_v, lowMask);
+  if constexpr (S4_T == BTLA_DTYPE::S4_FULLRANGE) {
+    auto s8 = _mm256_set1_epi8(8);
+    dst0 = _mm256_sub_epi8(dst0, s8);
+  } else {
+    dst0 = _mm256_slli_epi32(dst0, 4);
+  }
+  _mm256_storeu_si256(reinterpret_cast<__m256i*>(dstptr), dst0);
+}
+
 template <typename T>
 static inline void convert_s8_fp_v8(T* dstptr, int8_t* srcptr) {
   auto xmm = _mm_loadl_epi64(reinterpret_cast<__m128i*>(srcptr));
@@ -369,9 +384,11 @@ static inline BTLA_CODE decompress_s4_s8(utils::int4x2* srcptr, int8_t* dstptr,
     size_t elesize = static_cast<size_t>(row) * col;
     size_t ele16 = utils::padto_le(elesize, 16);
     size_t i = 0;
-    for (; i < ele16; i += 16) {
-      convert_s4_s8_16_sse<S4_T>(dstptr + i, reinterpret_cast<int8_t*>(srcptr + i / 2));
-    }
+    // for (; i < ele16; i += 16) {
+    //   convert_s4_s8_16_sse<S4_T>(dstptr + i, reinterpret_cast<int8_t*>(srcptr + i / 2));
+    // }
+    size_t ele32 = utils::padto_le(elesize, 32);
+    for (; i < ele32; i += 32) convert_s4_s8_32_avx<S4_T>(dstptr + i, reinterpret_cast<int8_t*>(srcptr + i / 2));
     for (; i < elesize; i += 2) {
       auto tmp = srcptr[i / 2];
       dstptr[i + 0] = kernel::ref::get_s8<S4_T>(tmp.x);
diff --git a/bestla/bestla/ut/bestla_ut.h b/bestla/bestla/ut/bestla_ut.h
index b9e40f54e..93edf44b1 100644
--- a/bestla/bestla/ut/bestla_ut.h
+++ b/bestla/bestla/ut/bestla_ut.h
@@ -63,7 +63,8 @@ static inline int auto_batch(size_t memsize) {
   GetCPUDevice();
   auto L3 = _cd->getL3CacheSize();
   size_t constexpr Enlarge = 4;
-  auto batch = L3 * Enlarge / memsize;
+  size_t constexpr TargetMem = 1LL << 30;
+  auto batch = TargetMem / memsize;
   return batch > 1 ? batch : 2;
 }