
It's a BIG gamble trying to get a Rad9500 (non-PRO) and mod it to a Rad9700. For a VERY brief time the 9500NONPRO were made on the 9700PCB mostly to get the early cards to maket while a 4 piped PCB was finalised, these cards had the 4 RAM chips all in a line along the top of the card. To make the mod possible you need a 9500nonPRO on a 9700PCB with 128MB which would give you the 256bitDDR and 8 pipes although 4 would be dormant. You then needed to mod the card in order to force all 8 pipes into being used, the 8 pipes is by far the most important part as with 4 pipes perf plain sucked. Even if you did/do get a 9500nonPRO based on the 9700PCB with 128MB and could awaken the dormant pipes the chances of the pipes working was under 50%. If you could get 8 pipes and had the 256bit DDR you then had a 9700nonPRO and by flashing the BIOS you could enable clock alterations and all 9500-9700 seemed to exceed 9700PRO speeds so basicly it was then easy to get a 9700PRO out of your 9500nonPRO .... if you could find the right type of card and were lucky enough to have 8 fully functional pipes. Considering the chances were tiny even back when the 9500 series was widely available I'd say it totally a waste of time now. Even back then the 9500PRO was a much better choice as you got 8 pipes guaranteed and a simple BIOS flash could almost always yield 9700nonPRO perf.

At stock speeds...
9500 is much slower than a 4200, you need to enable FULL AA & AF to compete with a stock 4200, the GF4TI were never designed to use FULL AA & AF (medium AA & AF is best).
9500PRO is significantly faster than a 9500 and you're at GF4TI4400/4800SE speeds, but enabling full AA & AF you'll be a lot faster than a GF4TI4600/4800.
9600PRO is a step down from 9500PRO, clock speeds are very high but now you're stuck with 4 pipes so are about 15% slower than 9500PRO so AA+AF to one side you're as fast a s a 4200.

So if you want to mod a card to a faster one it's back to the old method of choosing your card carefully and o/c'ing. There is a slight chance the 9800SE will be a moddable candidate. The 128bit DDR version (Rad9500PRO speeds IMHO) MAY be moddable to a 256bit version but it would only be a very short term thing and is unlikely. The 9800SE 256bit DDR (Rad9700nonPRO perf IMHO) may use a 9800PCB but again it's only likely to be a short term thing, that would give you a chance of enabling 8 pipes and effectively having a card faster than a Rad9800pro as it seems the 9800SE will be 4 piped 0.13mu! I wouldn't hold your breath though...