There's three cards in the 5800 series ( HD5830, HD5850 and HD5870) they all use the same Cypress chip so GPU-Z is detecting the Cypress chip but doesn't know which card its in, all it knows is that it must be a card from the 5800 series.
so that's why the model isn't showed in GPU-Z Thanks !
in cpu-z it shows the model if thats any help or at least in mine it shows
that will be great, I'll give it a try Thanks !
I tried CPU-z but nothing seems to work
The chip only reports itself as being a 5800, in order to show the model it would need to check stream processors and clock speeds which wouldnt necessarily be accurate like in the 4800 series the 4870 and 4890 were only differentiated by their clock speed, the 4850 was just a slower 4870 with GDDR3 instead of GDDR5, if its not a reliable method its best not to include it for them so no one can complain that they are wrong.