no. theres is a significant difference.
the v8420deluxe cards are clocked at 260mhz intead of the usual 250mhz for the core,
and 550mhz instead of the 444mhz DDR memory clock.
im most definitely gonna get myself a v8420d in the next month or so.
it will be the best choice among gf4ti4200s. also, it uses the larger 8layer pcb design like the 4400 and 4600s.
good luck!