Looking at single GPU products, here is a quick estimation of GPU performance scaling based off numbers from the internet,

PRODUCT FORM TDP(W) Xbox360 Factor ---------- ---------------- ------ -------------- A4-1200 Thin Tablet 4 0.25x A6-1450 Thick Tablet 8+ 0.4x A4-5000 Small Netbook 15 0.5x A10-5757M Largest Netbook 35 2.2x HD7970M Largest Notebook 75 8.5x HD7750 $100 Desktop GPU 75 3.6x HD7970 GHz $500 Desktop GPU 250 16.8x

The "thin tablet" probably is in the iPad4 size and power range, and looks to have similar GPU perf (1/4 of an Xbox360) but with a full DX11.1 feature set. The "thick tablet" almost reaches 1/2 Xbox360 range when in the increased clock state (a state which might be possible when plugged into a wall outlet). Integrated CPU/GPU beyond tablet ranges from 1/2x to 2x an Xbox360. Non-integrated GPU for notebook climbs to over 8x a Xbox360 on the high end. Current desktop GPUs starting at $100 are almost 4x an Xbox360, with high end non-SLI over 16x.

Total scaling range from tablet to desktop in this table is 1:64. If one targets 1080p/60Hz at roughly 8x the Xbox360 performance, scaling up to non-SLI highend PC provides 1440p/60Hz. The drop to largest netbook is a 4x perf loss from the target, probably requiring scaling geometry down by 4x, then dropping to 30Hz with half cost pixel shading (reduce post, lower complexity lighting, etc). Hitting a tiny 15W netbook requires another 4x scaling perhaps to 540p/30Hz with 4x cut in geometry.

This example 8x Xbox360 perf target in notebook form can be purchased currently for around $1100 (MSI GX60 1AC-021US).