XFX RADEON R9 280X XFX Radeon R9 280x is Tahiti clocked at 1080Mhz with 3GB GDDR5 clocked at 6200mhz. XFX Radeon R9 280x has a memory interface of 384bits with 2048 shader processors with support for directx 11.2. Sapphire Radeon R9 270x is Pitcairn clocked at 1020Mhz with 2GB GDDR5 clocked at 5600mhz. Sapphire Radeon R9 270x has a memory interface of 256bits with 1280 shader processors with support for directx 11.2. benchmark software we are using for testing XFX Radeon R9 280x and Sapphire Radeon R9 270x is as follows:- Battlefield 3, Bioshock Infinite, Dirt 3, Farcry 3, Hitman Absolution, Max Payne 3, Resident Evil 6 and Tomb Raider 3. CPU is AMD FX 8350 Vishera with Gigabyte GA78LMT S2P Motherboard using Windows 7 Operating System."