At the top end is the Radeon X1800 XT; this 16-pipe R520 will feature a 600MHz core clock, with a 256-bit memory bus connected to 512MB of GDDR3 memory clocked at 700MHz. The 600MHz core clock will give it a lower fill rate than the GeForce 7800 GTX (24-pipes at 430MHz), while the 700MHz memory clock will give it more memory bandwidth than the stock GTX (600MHz). Much like the GTX, the X1800 XT will be priced at $599.
R520 Information Hits Anandtech
If you would like to get all the juciest information on the R520 before it gets released later next month, you can head over to Anandtech’s “pre-NDA Extravaganza” and read up on a lot of it. The meat of it is that we will only see a 16 pipe version of this core despite older rumors and that clock speeds on the XT (top model) are going to be at 600 MHz core and 700 MHz memory! Oh and we will now have two more cards with 512 MB memory configurations stock from ATI by the looks of it.