WARP + Thinkpad query

[dewar@nile.gnat.com (Robert Dewar)]

I don't know if this is WARP or TP, but I first noticed it in upgrading
to a new thinkpad. I find now that disk activity in a background window
is tending to lockout keyboard input in a foreground window, sometimes
for as long as several seconds. Similarly, window repositioning and
redrawing is painfully slow if there is fierce disk activity in the 
background. I changed to

PRIORITY_DISK_IO=NO

but this has no effect.