Help pc recognises MSI Nvidia GEforce 7800 gtx 512mb video card only as 4800ti 128mb vid?

I have a MSI Nvidia Geforce 7800 gtx 512mb video card that I bought back in 2005 new. It ran perfectly fine in my old computer system. However I put it in my new system and the computer will only recognise it as a 4800ti with 128mb video. Not anywhere near what I want. I have gone to both nvidia and msi homepages and tried to download drivers but the pc still only will recognise it as a 4800. Any help will be appreciated. thanks|||You may have to remove the drivers completely with Driver Cleaner it will remove all the Nvidia Graphics Drivers then get the latest driver from Nvidia.com.