We have a PC which is about 15 months old. DS aged 10.5 plays games on it and it seems as if the PC is quicker than the keyboard (this sometimes happens to me when I am typing up notes). Is it worth getting something more robust?
How do you mean 'the PC is quicker than the keyboard'? What does it do?
Gaming keyboards are cool (I have one) but they're not usually a performance increase thing - they're designed to be particularly comfortable to type on, to give easy access to keys/combinations usually used in games, and many come with extras such as programmable macro keys you can customise to give you an edge in competitive games. I'm not sure this is what you're looking for.
The PC is BOUND to be quicker than the keyboard, as the processor can do a few hundred things in the time it takes to manually press a key!
But it sounds as if your word processor program is not running as quickly as it should. If you have other applications running, or something has 'hung up' somewhere could cause that.
So quit everything else except the program you are using, and see if that helps. Also if you have auto-correct spell checkers running, might affect it. (I'm a touch typist, and sometimes it takes a fraction of a second for characters to appear on the screen.)