i found that a no-brand usb to ps/2 adapter recommended at a ibm keyboard modifcation page has worked with no lag in games like doom3 on my athlonxp 2000. it is AUD$20 so perhaps this could be an alternative

it does seem to have a input throughput cap on it as when i mash the keyboard it will 'spurt' out characters. but not noticeable when typing at 90 wpm

the only identification of the adapteer is the model number WC7571, there is a photo of it from the store i bought it from in australia:

http://www1.jaycar.com.au/productVi...x=&SUBCATID=246