How are you reading the data from FX3 into PC. What functions of cyapi are you using. Paste that part of code here. I will look into it. Otherwise you can do onething, you can refer to the source code of the streamer application.
BOOL GetSensorData(BYTE *pOut, LONG bufsize)
bool bRequest = FALSE;
inOvLap.hEvent = CreateEvent(NULL, false, false, NULL);
UCHAR *inContext = USBDevice->BulkInEndPt->BeginDataXfer(pOut,bufsize, &inOvLap);
bRequest = USBDevice->BulkInEndPt->FinishDataXfer(pOut,bufsize, &inOvLap,inContext);
return bRequest ;
another question is that it looks like that the bufsize can't be too large,or this fuction will return FALSE, what should i do?
and i can't find cyusb.sys for 64 bit systerm.