You can easily get the core above Pro speeds. I had a 9600 that would do 452mhz and maybe even more on the stock cooling. The memory is another thing though. The 9600 I had, used 5ns memory which ='s 200mhz(400mhz ddr). But amazingly, It would go to 512Mhz! before it started corrupting the video. So, I was able to get it pretty darn close to Pro speeds. Its mainly the memory that you will be concerned with getting overclocked. I was able to get that 9600 I had up to about 90-95% of the performance of a 9600 Pro. Not to shabby for a $70 video card. Well, anyways, hopefully this helped somewhat.
Jason