Firstly, in my opinion, better to bench with 2005 to measure your progress as its more graphics biased. I would not go above 1.5V myself, do you have stock or aftermarket cooling? 1.5V gives me 740 on the core, even if yours is not as lucky you should make 720 with 1.5V but dont go there straight away, there is a fine line here and the Idle temps once you get to 1.475V are unreliable in as much as at stock voltage the difference at a speed between idle and full load may be say 20C but at 1.5V the difference could be 30+C so keep your eye on those temps.
Combine increased GPU temps with memory overclocks and its going to get warm in there, r, increase the memory volts a little but decrease the MVDDQ by about the same, it helps memory stability and lowers your temps by about 5C (but do this at end), make sure when raising volts you do so in no more than 0.25V increments and then within that raise GPU core by maximum of 10Mhz (preferably just 5 but some are impatient!), test it say in 3D Mark 2005 (if you are not using ATi tool) for just 3 or 4 minutes before keeping at same volts but raising Mhz on core until you max out at that voltage then move up the volts and repeat.
Again in my opinion and from my personal experience, do not even attempt to overclock the memory until you have done everything with the core, once you have found your max core at the max voltage you are prepared to attempt then think about the memory, doing both together as you go along can accasionally cause instability and at the end of the day, core increase is MUCH more relevant than memory speed increase, in performance terms a 10Mhz core increase is worth anything in the region of 40Mhz+ in memory speed.
. at the time i didnt have a floppy drive so i created some bootable cds. the bootable cds wouldnt work for reasons unknown, i created like 5 of them, none would really get working so i jsut caved in and attatched a floppy drive. created one with atiflash, didnt work, reasons unknown, maybe because its a HIS ICEQ3 x1800gto so i used flashrom240, 237 and 16p. none worked. the same problems would come up-
...I too own a X1800 XT 512
...OC´ing stock cooler@675/792 so far and got 7764@3DMark05 and with only 4675 for CPU...Using ATITool 0.26 and altered VGPU to 1.400 V.**MVDDC/Q to 2.108 V. I´ll let it run for a few days to check behavior of system...I´ll be back.
