Personal notes: X1900 XT in comparison to X1800 XT

A glimpse at X1900 XT additional traits:

• 90 nm process (this is not an improvement over X1800! just my note).

• 3 times the number of ALUs (Arithmetic Logic Unit) compared to X1800 XT , that is 16 x 3 = 48 ALUs or 'shader processor'.
• This increase in ALUs accounts for the 20% more transistors that had to be added to the GPU.
• Inclusion of 'Fetch4' - a method to speed up Shadow Mapping.

Taken from HardOCP :
"It works by exploiting the fact that most textures are composed of color values, each consisting of four components (Red, Green, Blue, and Alpha or transparency). The texture units are designed to sample and filter all four components from one texture address simultaneously. However, when looking up different types of textures with single-component values (such as shadow maps), Fetch4 instead allows four values from adjacent addresses to be sampled simultaneously. This effectively increases the texture-sampling rate by a factor of 4.

With Ultra-Threading technology providing fast flow control and Fetch4 providing fast texture lookups, the Radeon X1900 can render attractive soft shadows at speeds approaching those of traditional hard-edged shadow mapping techniques."

• Ramp up Higher-Z by adding 50% more on-chip memory compared to X1800 XT.
  

All above would justify on beating 7800 GTX 512. What a recipe for success!