diff --git a/Makefile.win b/Makefile.win
index 48fd71b..4ceb41b 100644
--- a/Makefile.win
+++ b/Makefile.win
@@ -9,7 +9,7 @@ REGRESS_OPTS = --inputdir=test --load-extension=$(EXTENSION)
 
 # For /arch flags
 # https://learn.microsoft.com/en-us/cpp/build/reference/arch-minimum-cpu-architecture
-OPTFLAGS =
+OPTFLAGS = /arch:AVX2
 
 # For auto-vectorization:
 # - MSVC (needs /O2 /fp:fast) - https://learn.microsoft.com/en-us/cpp/parallel/auto-parallelization-and-auto-vectorization?#auto-vectorizer
diff --git a/src/halfvec.h b/src/halfvec.h
index e0ab7c6..f737fcf 100644
--- a/src/halfvec.h
+++ b/src/halfvec.h
@@ -8,7 +8,7 @@
 #include "vector.h"
 
 /* F16C has better performance than _Float16 (on x86-64) */
-#if defined(__F16C__)
+#if defined(__F16C__) || defined(__AVX2__)
 #define F16C_SUPPORT
 #elif defined(__FLT16_MAX__)
 #define FLT16_SUPPORT