This post will give a brief summary of the Exadata Database Machine X3 as it was announced at the Oracle Open World by Larry Ellision:

(URL above is the complete Keynote; X3 announcement comes at 31:29)

The X3 Storage Servers have 4 times the Flash Capacity than X2: Each cell comes with 1600 GB, using Oracle’s Sun Flash Accelerator F40 PCIe Card now

The X3 Database Servers have now 2 x Eight-Core Intel® Xeon® E5-2690(SandyBridge) Processors instead of 2 x Six-Cores in X2

They have 128 GB memory each, instead of 96 GB on X2

The price of an X3 Rack remains the same except for the Software Licenses that are computed by the number of cores.

The X3 Entry Level Rack is now 1/8 Rack. It has got the same hardware as a 1/4 rack, but half of the cores, memory and storage capacity disabled.

Not only on X3, the Flash Cache will now work as a Write Back Cache. Older versions will be enabled to use Write Back Flash Cache with a Software Update.

More details:

X3-2 DBM

X3-2 Cell

X3 vs X2 video