You can use this patch if you are experiencing problems with overclocking under Windows 2000 with the following symptoms: core and memory clock frequencies are always reverted to defaults after reboot.
It is known bug of Detonator drivers for Windows 2000 and it was fixed in Detonator 12.90.
Due to incorrect memory clock validation NvXTInit procedure always resets memory clock to defaults when it is above 400MHz. This problem is caused by the bug into videomemory type detection.
Windows 9x drivers use the following validation interval for memory clock:
80-400 MHz for the boards equipped with SDR memory
80-800 MHz for the boards equipped with DDR memory
Windows 2000 driver cannot correctly detect videomemory type because it checks GeForce256 DDR device ID only. So driver detects the rest boards as SDR and uses invalid validation interval on DDR boards.
If you are using pre-12.90 drivers, you may use this patch script. It will made some corrections in driver and force it to use 80-800Mz overclocking range regardless of videomemory type.