I've tried several fixes for this including disabling CL, changing cache settings, and reducing drawing mode from adavanced to basic. Nothing is working.
These are my specs..
Adobe Photoshop Version: 13.0 (13.0 20120315.r.428 2012/03/15:21:00:00) x64
Operating System: Windows 7 64-bit
System architecture: AMD CPU Family:15, Model:10, Stepping:0 with MMX, SSE Integer, SSE FP, SSE2, SSE3
Physical processor count: 6
Processor speed: 2693 MHz
Built-in memory: 6143 MB
Free memory: 4351 MB
Memory available to Photoshop: 5374 MB
Memory used by Photoshop: 83 %
Image tile size: 132K
Image cache levels: 4
OpenGL Drawing: Enabled.
OpenGL Drawing Mode: Basic
OpenGL Allow Normal Mode: True.
OpenGL Allow Advanced Mode: True.
OpenGL Allow Old GPUs: Not Detected.
Video Card Vendor: ATI Technologies Inc.
Video Card Renderer: ATI Radeon HD 5800 Series
Display Bounds:= top: 0, left: 0, bottom: 1050, right: 1680
Video Card Number: 1
Video Card: ATI Radeon HD 5800 Series
Driver Version: 8.980.0.0
Driver Date: 20120611000000.000000-000
Video Card Driver: aticfx64.dll,aticfx64.dll,aticfx64.dll,aticfx32,aticfx32,aticfx32,atiumd64.dll,atidxx64.d ll,atidxx64.dll,atiumdag,atidxx32,atidxx32,atiumdva,atiumd6a.cap,atitmm64.dll
Video Mode: 1680 x 1050 x 4294967296 colors
Video Card Caption: ATI Radeon HD 5800 Series
Video Card Memory: 1024 MB
Video Rect Texture Size: 16384
Photoshop scratch has async I/O enabled
C:\, 919.2G, 807.9G free
Another option suggested I disabled GL but the advanced interface did not have the open GL option visible in the same location as the guide.
I did not have brush lag until I started using the air brush. I did increase canvas size and make the file much larger but the lag did not happen until after I switched brush types. It is possible that I did not notice the lag until I switched.