Their cores are both clocked @ 250 MHz, but because the GeForce 2 is so very starved for memory bandwidth, the GeForce 2 Ultra's superior memory speed and therefor superor memory bandwidth is able to feed the chip the bandwidth it needs. Although with overclocking there is a chance that the GeForce 2 Ti might be a little bit better with the cores being more mature you may be able to push the core further and be able to have the memory hit equal or higher speeds than the Ultra...