c# - how to improve the performance of streamwriter -

i'm working on smart device compact framework 3.0 i'm using streamwriter class write data on file. file size 256kb it's taking 60 seconds save file.

here code:

using (streamwriter sw = new streamwriter(tmppath, true)) {     sw.autoflush = true;      sw.writeline(_rm.getstring("key"));      sw.writeline(rm.getstring("key1") + "\t" + controller.time.tostring("yyyy-mm-ddhh:mm:ss"));      sw.writeline(rm.getstring("name") + "\t" + controller.systemname);     sw.writeline(rm.getstring("systemname") + "\t" + stctrlname);     sw.writeline(rm.getstring("systemid") + "\t" + stctrlid);      sw.writeline();      controller.getversion(out major, out minor, out revision, out build);     sw.writeline(rm.getstring("build") + string.format("\t{0}.{1}.{2}", major, minor, build));      sw.writeline(optionssection(systeminfo.moduletype.control));     sw.writeline();       sw.writeline(optionssection(systeminfo.moduletype.drive));     sw.writeline();       sw.writeline(optionssection1());       string header = formatmsg(stseqno, sttype, stdomain, stid, sttitle, stdate, rm.getstring("key2"), stargs);      using (log evlog = new log(log.domaintype.all))     {         sw.writeline();          // {0} log messages         string domain = string.format(rm.getstring("stbevt_txt_logfilenewdomain"), log.geteventlogdescription(log.domaintype.all));         sw.writeline(domain);          // write column headings         sw.writeline(header);          string str = string.empty;          foreach (eventmessage em in evlog.getevents())         {             sw.writeline(formatmsg(em.sequencenumber, em));         }     }      log.domaintype domtype = log.domaintype.noofdomains;     foreach (eventmessage em in allevents)     {         if (_progressbar._pbar.value >= _progressbar._pbar.maximum)         {             _progressbar._pbar.value = 0;         }         else         {              _progressbar._pbar.value += 1;         }         if (em.domain != domtype)         {             sw.writeline();              // {0} log messages             string domain = string.format(rm.getstring("stbevt_txt_logfilenewdomain"), log.getlogdescription(em.domain));             sw.writeline(domain);              // write column headings             sw.writeline(header);              domtype = em.domain;         }          sw.writeline(formatmsg(em.sequencenumber, em));      } 

please tell me how can improve performance such take 10 15seconds save 256kb data.