Radeon 8500的基本結構與當時的其他顯示卡差不多；它擁有四個像素單元，每個像素單元擁有兩個紋理單元。它亦支援DirectX 8.1的頂點著色引擎和像素著色引擎，它的兩個頂點著色引擎被稱為Charisma Engine II，為新的頂點著色程式和舊的DirectX 7硬體T&L都提供出色的效能。"R200"核心was more capable with regards to advanced pixel and vertex shading when compared to the competition at the time (GeForce 3 and 4), supporting DirectX 8.1 (pixel shader 1.4) with Pixel Tapestry II. R200 also had the most advanced memory bandwidth saving hardware of the time onboard, the next version of ATI's innovative HyperZ, HyperZ II. The chip was capable of dual-monitor display, through the Hydravision technology. Finally, R200 was equipped with Video Immersion II, ATI's advanced video decoding engine with high quality hardware deinterlacing. A DVI-I to component conversion connector was available for home theater enthusiasts.
R200支援像素著色器版本1.4，相對1.x版本的設計，這個修訂版本是意義重大的。鑒於PS1.2和1.3隻是PS1.1的改進版，PS1.4 changed things around quite significantly. Notable instructions include "phase", "texcrd", and "texld". The phase instruction allows a shader to operate on two separate "phases" (2 passes through the hardware), effectively doubling the maximum number of texture addressing and arithmetic instructions, and potentially allowing the number of passes required for an effect to be reduced. This allowed not only more complicated effects, but can also allow a speed boost by utilizing the hardware more efficiently. The "texcrd" instruction moves the texture coordinate values of a texture into the destination register, while the "texld" instruction will load the texture at the coordinates specified in the source register to the destination register.
DirectX 8.0
Pixel Shader 1.1 DirectX 8.1
Pixel Shader 1.4
最大紋理輸入 4 6
最長指令長度 12 instructions
(up to 4 texture sampling, 8 color blending) 22 instructions
(up to 6 texture sampling, 8 texture addressing, 8 color blending)
指令集 13 address operations, 8 color operations 12 address / color operations
紋理定址模式 40 virtually unlimited
While R200 lost a texture unit per pipeline compared to R100's 2x3 architecture, R200's pipelines were far more robust. Each could address a total of 6 texture layers in a single pass if the application was coded to do so. The chip achieved this by a term commonly known as ‘loop-back’. Increasing the flexibility in the number of textures allowed per pass reduced the number of times the card was forced into ‘multi-pass rendering’, a performance draining scenario which increases both the geometry required for the scene (by needing to recalculate the entire scene for the number of times it is passed) and the external memory bandwidth used. Therefore, the chip's overall efficiency and performance was increased by enabling more textures to be addressed per pass. Testing using Serious Sam The Second Encounter showed a 16 % performance increase at 1600x1200 resolution with quad texturing and bilinear filtering (in comparison with dual and triple texturing).
特色
利用Radeon 256，ATI透過"RIP" mapping方法引進了各異向性過濾。"RIP" mapping技術上其實不是各異向性過濾，但可提供相似的效果，效能損失亦較少。不幸地，這種方法只在配合雙線性過濾時有效。The implementation was also quite angle dependent, meaning that the texture had to be at a certain angle to the viewport or it would not be sharpened. Of course this reduced the computational load, but it also made it possible to see textures that were merely bilinear filtered right beside nearby sharpened textures. Radeon 8500 uses the same technique, but with some refinements to improve quality while still maintaining excellent performance. When anisotropic was enabled on 8500, the boundaries between mip maps, normally easily seen when using bilinear filtering instead of trilinear, were fairly well hidden and the anisotropic mode greatly improves texture sharpness at medium to long distances. Still, the remaining angle dependency and forced-bilinear were controversial from a quality standpoint. NVIDIA's GeForce 4 Ti series offered a far more accurate anisotropic implementation, but it also carried with it a heavy performance hit.
ATI沒有為基於BSD的作業系統推出過任何驅動程式，但就為執行在Linux中的X Window System提供驅動程式。而基於PowerPC和Mac OS X作業系統的Mac mini和iBook G4就採用了Radeon 9200顯示卡。
一些Linux用家社區的分支，which prefer to avoid the IP-encumbered ATI drivers due to stability and long term maintainability reasons, still prefer the R200-based chips, as they are among the fastest modern video cards with stable open source drivers.
驅動程式
ATI的Catalyst Drivers支援所有R200以上的Radeon顯示卡，除了Windows XP x64，直至Catalyst 6.6推出。ATI亦提供舊有驅動程式，Catalyst 6.11則支援9250以下的Radeon顯示卡。
References
"ATi Radeon 8500 64 MB Review (Part 1)" by Dave Baumann, Beyond3D.Com, 2002年03月29日, retrieved 2006年01月14日
"ATi Radeon 8500 64 MB Review (Part 2)" by Dave Baumann, Beyond3D.Com, 2002年04月04日, retrieved 2006年01月14日
"ATI RADEON 9100 Based Graphics Cards Review: Gigabyte and PowerColor Solutions" by Tim Tscheblockov, X-Bit Labs, 2003年02月05日, retrieved 2006年01月09日
"ATI's Radeon 8500 & 7500: A Preview" by Anand Lal Shimpi, Anandtech, 2001年08月14日, retrieved 2006年01月09日
