The following subkey and value can be found under the following key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Serial
The Serial subkey contains a subkey named Parameters, under which is a set of subkeys typically named SerialX where X is a whole number. A system administrator must place these subkeys and values into the Registry. You can only define and manipulate these values by using Registry Editor.
For example, under the Serial2 subkey, the following optional value entry can appear, and does affect system performance.
ForceFifoEnable REG_DWORD 0 or 1
If the value is 1 and the hardware supports a FIFO buffer (for example, the NS 16550AFN), the driver enables the FIFO. Not all FIFOs are reliable. If the application or the user notices lost data or no data transmission, it is recommended that this value be set to 0.
Default: 1