Why it have to use more time to m.Write?

[huntor001]

int htv=id(101 win("123" "Afx:400000:*" "" 0x800));out htv
int i=SendMessage(htv TVM_GETNEXTITEM TVGN_ROOT 0);out "hItem=%i" i

__ProcessMemory m; int pid
TVITEMEX tt
m.Alloc(htv 1000)
GetWindowThreadProcessId(htv &_i);pid=_i ;out _i

int a=m.address; out "a=%i" a
tt.pszText=+(a+200)
tt.cchTextMax=260
tt.hItem=i
tt.mask=TVIF_TEXT
out "time=%i" GetTickCount
m.Write(&tt sizeof(tt))
out "time=%i" GetTickCount
_i=SendMessage(htv TVM_GETITEMW 0 a);out _i
if(_i) m.ReadStr(_s 20 200 1);out "%s %i" _s _s.len
m.Free

TimeInterval =50-150ms,only in m.Write,why......? :?: