The latest rumors on the PlayStation 4 revealed this specifications:

• Holographic Disc (HVD)
• Lossless 9.1 Channel
• 220GB-1TB Harddrive, Flash, External
• 6Gb/s (SATA-600)
• Full Deep Color
• x.v.Color
• Wireless, Vibration, Motion Sense (3D), Wind, Shock
• 100 Gbit Eithernet wired, Wi-Fi 802.11b/g/n wireless
• QF-HDTV (3840×2160p)
• 1024MB GDDR4 Video Ram
• 1024MB GDDR4 System Ram

It is unknown if these are true specifications of the future PlayStation 4.

Source