Thank you for contacting NVIDIA Customer Care.
I understand from your email, that you have an nForce 3 250 chipset based motherboard and you are looking for the updated gart drivers in Windows XP 64-bit Operating System.
I am sorry, we do not have gart drivers for the nForce 3 250 chipset based motherboard. I would request you to contact the motherboard manufacturer Asrock for the drivers. We at NVIDIA manufacture only the chipsets for the desktops and laptops. The cards are manufactured and sold by the third parties or the OEMs. We do not build graphics cards or motherboards. Please check with Asrock for the motherboard chipset drivers, which will include the gart drivers as well. The contact number of Asrock is 1-909-590-8308.
Please feel free to contact us, if you have any further questions.