The ZOGIS 9800GTX was a beast when it came to overclocking. I was able to overclock the stock GPU clock of 675MHz all the way up to 823MHz! A 148MHz overclock is quite good if you ask me. I was also able to get the stock memory clock of 1100MHz all the way up to 1274MHz - a 174MHz increase. The shader clock was stock at 1688MHz, but I was able to bring it up to 2001MHz. The core clock was able to go higher, but the memory kept having to go down, so these numbers are the absolute highest that I could get for all three of the variables. I've never overclocked any other video card nearly this much in all of my years of overclocking. I'm thoroughly impressed with the ZOGIS 9800GTX's overclocking ability.