Please excuse the blatant copy/paste...
Designed by SAPPHIRE, the new HD 4850 X2 comprises two complete HD 4850 graphics systems on a single PCI-Express card connected by an on-board PCI Express Gen 2 bridge chip. Each GPU has 800 stream process units and a 256-bit memory interface driving 1GB of GDDR3 memory, making a total of 2GB on-board memory. Four Dual Link DVI outputs are provided as well as TV-Out. This provides a choice of Multi-monitor operation or CrossFire mode in which 3D applications such as games use both on-board GPUs together to deliver a single accelerated output on the Primary display with industry leading levels of performance.
2 GB or 1GB of GDDR3 memory & 2.0 TeraFLOPS of GPU power
DirectX® 10.1 & PCI Express® 2.0 support
1600 stream processing units & 2 x 256-bit memory interface
24x custom filter anti-aliasing (CFAA) and high performance anisotropic filtering
Dual mode ATI CrossFireX multi-GPU support for highly scalable performance
Dynamic geometry acceleration & DVD Upscaling
Game physics processing capability & Dynamic Contrast
ATI Avivo HD video and display technology & Dynamic power management with ATI PowerPlay technology
Unified Video Decoder 2 (UVD 2) for Blu-rayand HD Video
Accelerated Video Transcoding(AVT) & Built-in HDMI with 7.1 surround sound support
Scan linky http://www.scan.co.uk/Products/1GB-Sapphire-HD-4850-X2-PCI-E-20-(x16)-1986MHz-GDDR3-GPU-625MHz-1600-Cores-4x-DVI-I-HDTV
Manufacturer linky http://www1.sapphiretech.com/us/products/products_overview.php?gpid=265
Be aware that the manufacturer does recommend a 650W PSU minimum!
This, i believe, is a good price, hopefully save somebody some cash :)
Hexus.net members can get free delivery...not sure on the details so price mentioned is incluisve of a delivery charge