diff --git a/libavutil/x86/tx_float_init.c b/libavutil/x86/tx_float_init.c
index e60faf7fa6..108f9b4b04 100644
--- a/libavutil/x86/tx_float_init.c
+++ b/libavutil/x86/tx_float_init.c
@@ -71,24 +71,31 @@ const FFTXCodelet * const ff_tx_codelet_list_float_x86[] = {
     TX_DEF(fft4_inv, FFT,  4,  4, 2, 0, 128, NULL,  sse2, SSE2, AV_TX_INPLACE | FF_TX_INVERSE_ONLY, 0),
     TX_DEF(fft8,     FFT,  8,  8, 2, 0, 128, b8_i0, sse3, SSE3, AV_TX_INPLACE, 0),
     TX_DEF(fft8_ns,  FFT,  8,  8, 2, 0, 192, b8_i0, sse3, SSE3, AV_TX_INPLACE | FF_TX_PRESHUFFLE, 0),
-    TX_DEF(fft8,     FFT,  8,  8, 2, 0, 256, b8_i0, avx,  AVX,  AV_TX_INPLACE, 0),
-    TX_DEF(fft8_ns,  FFT,  8,  8, 2, 0, 320, b8_i0, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE, 0),
-    TX_DEF(fft16,    FFT, 16, 16, 2, 0, 256, b8_i2, avx,  AVX,  AV_TX_INPLACE, 0),
-    TX_DEF(fft16_ns, FFT, 16, 16, 2, 0, 320, b8_i2, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE, 0),
-    TX_DEF(fft16,    FFT, 16, 16, 2, 0, 288, b8_i2, fma3, FMA3, AV_TX_INPLACE, 0),
-    TX_DEF(fft16_ns, FFT, 16, 16, 2, 0, 352, b8_i2, fma3, FMA3, AV_TX_INPLACE | FF_TX_PRESHUFFLE, 0),
+    TX_DEF(fft8,     FFT,  8,  8, 2, 0, 256, b8_i0, avx,  AVX,  AV_TX_INPLACE, AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft8_ns,  FFT,  8,  8, 2, 0, 320, b8_i0, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE,
+           AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft16,    FFT, 16, 16, 2, 0, 256, b8_i2, avx,  AVX,  AV_TX_INPLACE, AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft16_ns, FFT, 16, 16, 2, 0, 320, b8_i2, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE,
+           AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft16,    FFT, 16, 16, 2, 0, 288, b8_i2, fma3, FMA3, AV_TX_INPLACE, AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft16_ns, FFT, 16, 16, 2, 0, 352, b8_i2, fma3, FMA3, AV_TX_INPLACE | FF_TX_PRESHUFFLE,
+           AV_CPU_FLAG_AVXSLOW),
 
 #if ARCH_X86_64
-    TX_DEF(fft32,    FFT, 32, 32, 2, 0, 256, b8_i2, avx,  AVX,  AV_TX_INPLACE, 0),
-    TX_DEF(fft32_ns, FFT, 32, 32, 2, 0, 320, b8_i2, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE, 0),
-    TX_DEF(fft32,    FFT, 32, 32, 2, 0, 288, b8_i2, fma3, FMA3, AV_TX_INPLACE, 0),
-    TX_DEF(fft32_ns, FFT, 32, 32, 2, 0, 352, b8_i2, fma3, FMA3, AV_TX_INPLACE | FF_TX_PRESHUFFLE, 0),
+    TX_DEF(fft32,    FFT, 32, 32, 2, 0, 256, b8_i2, avx,  AVX,  AV_TX_INPLACE, AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft32_ns, FFT, 32, 32, 2, 0, 320, b8_i2, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE,
+           AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft32,    FFT, 32, 32, 2, 0, 288, b8_i2, fma3, FMA3, AV_TX_INPLACE, AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft32_ns, FFT, 32, 32, 2, 0, 352, b8_i2, fma3, FMA3, AV_TX_INPLACE | FF_TX_PRESHUFFLE,
+           AV_CPU_FLAG_AVXSLOW),
 #if HAVE_AVX2_EXTERNAL
-    TX_DEF(fft_sr,    FFT, 64, 131072, 2, 0, 256, b8_i2, avx,  AVX,  0, 0),
-    TX_DEF(fft_sr_ns, FFT, 64, 131072, 2, 0, 320, b8_i2, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE, 0),
-    TX_DEF(fft_sr,    FFT, 64, 131072, 2, 0, 288, b8_i2, avx2, AVX2, 0, AV_CPU_FLAG_AVXSLOW),
-    TX_DEF(fft_sr_ns, FFT, 64, 131072, 2, 0, 352, b8_i2, avx2, AVX2, AV_TX_INPLACE | FF_TX_PRESHUFFLE,
+    TX_DEF(fft_sr,    FFT, 64, 131072, 2, 0, 256, b8_i2, avx,  AVX,  0, AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft_sr_ns, FFT, 64, 131072, 2, 0, 320, b8_i2, avx,  AVX,  AV_TX_INPLACE | FF_TX_PRESHUFFLE,
            AV_CPU_FLAG_AVXSLOW),
+    TX_DEF(fft_sr,    FFT, 64, 131072, 2, 0, 288, b8_i2, avx2, AVX2, 0,
+           AV_CPU_FLAG_AVXSLOW | AV_CPU_FLAG_SLOW_GATHER),
+    TX_DEF(fft_sr_ns, FFT, 64, 131072, 2, 0, 352, b8_i2, avx2, AVX2, AV_TX_INPLACE | FF_TX_PRESHUFFLE,
+           AV_CPU_FLAG_AVXSLOW | AV_CPU_FLAG_SLOW_GATHER),
 #endif
 #endif