It really depends what you mean by "a MIDI cord".
If you mean just the cable, then no.
However, if you mean a MIDI to USB adapter, including the drivers, especially if they're the generic Windows USB MIDI drivers, then a big YES.
Not only will there be latency there will also be jitter. In the conversion process of MIDI to USB there is always a delay and the timing is not constant.
So the amount of delay changes. This variation in delay is called jitter.
Drivers written specifically for a MIDI/USB device tend to have lower MIDI latency and less jitter.
If you can connect the keyboard directly via its own USB cable then this is usually the best solution.
The next best is to use e.g. a PCI or PCMCIA card with its own MIDI interface sockets.
If you have to use USB, buying a quality device with its own drivers is the next.
And worst is a cheap interface using Windows drivers.
Any use?
SysExJohn.