diff --git a/memcheck/tests/overlap.vgtest b/memcheck/tests/overlap.vgtest
index 54a0baacf..eba65897c 100644
--- a/memcheck/tests/overlap.vgtest
+++ b/memcheck/tests/overlap.vgtest
@@ -1,2 +1,4 @@
 prog: overlap
 vgopts: -q
+# https://bugs.kde.org/show_bug.cgi?id=402833
+prereq: ! ../../tests/arch_test amd64
diff --git a/shared/vg_replace_strmem.c b/shared/vg_replace_strmem.c
index 8de6a0698..79e640189 100644
--- a/shared/vg_replace_strmem.c
+++ b/shared/vg_replace_strmem.c
@@ -1128,8 +1128,15 @@ static inline void my_exit ( int x )
 #define MEMMOVE(soname, fnname)  \
    MEMMOVE_OR_MEMCPY(20181, soname, fnname, 0)
 
-#define MEMCPY(soname, fnname) \
+/* See https://bugs.kde.org/show_bug.cgi?id=402833
+   why we disable the overlap check on x86_64.  */
+#if defined(VGP_amd64_linux)
+ #define MEMCPY(soname, fnname) \
+   MEMMOVE_OR_MEMCPY(20180, soname, fnname, 0)
+#else
+ #define MEMCPY(soname, fnname) \
    MEMMOVE_OR_MEMCPY(20180, soname, fnname, 1)
+#endif
 
 #if defined(VGO_linux)
  /* For older memcpy we have to use memmove-like semantics and skip
@@ -1704,6 +1711,14 @@ static inline void my_exit ( int x )
 
 /*-------------------- memcpy_chk --------------------*/
 
+/* See https://bugs.kde.org/show_bug.cgi?id=402833
+   why we disable the overlap check on x86_64.  */
+#if defined(VGP_amd64_linux)
+ #define CHECK_OVERLAP 0
+#else
+ #define CHECK_OVERLAP 1
+#endif
+
 #define GLIBC26___MEMCPY_CHK(soname, fnname) \
    void* VG_REPLACE_FUNCTION_EZU(20300,soname,fnname) \
             (void* dst, const void* src, SizeT len, SizeT dstlen ); \
@@ -1717,7 +1732,7 @@ static inline void my_exit ( int x )
       RECORD_COPY(len); \
       if (len == 0) \
          return dst; \
-      if (is_overlap(dst, src, len, len)) \
+      if (CHECK_OVERLAP && is_overlap(dst, src, len, len)) \
          RECORD_OVERLAP_ERROR("memcpy_chk", dst, src, len); \
       if ( dst > src ) { \
          d = (HChar *)dst + len - 1; \