Hi,
I am using FT2232H mini module to write to a N25P256MB memory with an application in C on Windows 10 Professional x64 operation system. I use libMPSEE library v 1.0.0.1, 2014 and FTDI D2XX driver (version 2.12.28) downloaded from https://www.ftdichip.com/Drivers/D2XX.htm.  My problem is that I obtained different speeds for writing data in that memory. For example, for write consecutive pages (256 bytes) with “SPI_Write” function, it  took  16 ms or 60 ms in the same execution of program.

This are the parameters that I used for “SPI_InitChannel” function:
channelConf.ClockRate = 30000000; // 30 MHz;
channelConf.LatencyTimer = 2; //2ms
channelConf.configOptions = SPI_CONFIG_OPTION_MODE0 | SPI_CONFIG_OPTION_CS_DBUS3 | SPI_CONFIG_OPTION_CS_ACTIVELOW;
channelConf.Pin = 0x00000000;

This are the functions that I used to write a page (256 bytes) on memory

   // SET WRITE ENABLE
   sizeToTransfer = 1;
   sizeTransfered = 0;
   buffer[0] = 0x06;   /// WRITE ENABLE   
   status = SPI_Write(ftHandle, buffer, sizeToTransfer, &sizeTransfered,
      SPI_TRANSFER_OPTIONS_SIZE_IN_BYTES |
      SPI_TRANSFER_OPTIONS_CHIPSELECT_ENABLE |
      SPI_TRANSFER_OPTIONS_CHIPSELECT_DISABLE);
       // WRITE DATA
   sizeToTransfer = 261;
   sizeTransfered = 0;
   buffer[0] = 0x02;   /// WRITE COMMAND
   //buffer[0] = 0x12;   /// WRITE COMMAND
   buffer[1] = ((address & 0xff000000) >> 24) & 0x000000ff;
   buffer[2] = ((address & 0x00ff0000) >> 16) & 0x000000ff;
   buffer[3] = ((address & 0x0000ff00) >> & 0x000000ff;
   buffer[4] = (uint8)address;
   status = SPI_Write(ftHandle, buffer, sizeToTransfer, &sizeTransfered,
         SPI_TRANSFER_OPTIONS_SIZE_IN_BYTES |
         SPI_TRANSFER_OPTIONS_CHIPSELECT_ENABLE |
         SPI_TRANSFER_OPTIONS_CHIPSELECT_DISABLE);

Any suggestion on what the problem could be or how to resolve this?