Вопрос про видеокарту и пиксель шейдеры. Поддерживает ли видеокарта ATI Radeon HD 3600 эти самые пиксель шейдеры 3.0?

Поддерживает.
И даже 4.1 тоже поддерживает.
Только сама по себе производительность этой видеокарты по современным меркам очень невелика.. .

ATI Radeon™ HD 3600 Series GPU Specifications
378 million transistors on 55nm fabrication process
PCI Express 2.0 x16 bus interface
128-bit DDR2/GDDR3/GDDR4 memory interface
Ring Bus Memory Controller
Fully distributed design with 256-bit internal ring bus for memory reads and writes
Microsoft® DirectX® 10.1 support
Shader Model 4.1
32-bit floating point texture filtering
Indexed cube map arrays
Independent blend modes per render target
Pixel coverage sample masking
Read/write multi-sample surfaces with shaders
Gather4 texture fetching
Unified Superscalar Shader Architecture
120 stream processing units
Dynamic load balancing and resource allocation for vertex, geometry, and pixel shaders
Common instruction set and texture unit access supported for all types of shaders
Dedicated branch execution units and texture address processors
128-bit floating point precision for all operations
Command processor for reduced CPU overhead
Shader instruction and constant caches
Up to 40 texture fetches per clock cycle
Up to 128 textures per pixel
Fully associative multi-level texture cache design
DXTC and 3Dc+ texture compression
High resolution texture support (up to 8192 x 8192)
Fully associative texture Z/stencil cache designs
Double-sided hierarchical Z/stencil buffer
Early Z test, Re-Z, Z Range optimization, and Fast Z Clear
Lossless Z & stencil compression (up to 128:1)
Lossless color compression (up to 8:1)
8 render targets (MRTs) with anti-aliasing support
Physics processing support
Dynamic Geometry Acceleration
High performance vertex cache
Programmable tessellation unit
Accelerated geometry shader path for geometry amplification
Memory read/write cache for improved stream output performance
Anti-aliasing features
Multi-sample anti-aliasing (2, 4, or 8 samples per pixel)
Up to 24x Custom Filter Anti-Aliasing (CFAA) for improved quality
Adaptive super-sampling and multi-sampling
Temporal anti-aliasing
Gamma correct
Super AA (CrossFire configurations only)
All anti-aliasing features compatible with HDR rendering
Texture filtering features
2x/4x/8x/16x high quality adaptive anisotropic filtering modes (up to 128 taps per pixel)
128-bit floating point HDR texture filtering
Bicubic filtering
sRGB filtering (gamma/degamma)
Percentage Closer Filtering (PCF)
Depth & stencil texture (DST) format support
Shared exponent HDR (RGBE 9:9:9:5) texture format support
OpenGL 3.2 support
ATI Avivo™ HD Video and Display Platform
Dedicated unified video decoder (UVD) for H.264/AVC and VC-1 video formats
High definition (HD) playback of both Blu-ray and HD DVD formats
Hardware MPEG-1, MPEG-2, and DivX video decode acceleration
Motion compensation and IDCT
ATI Avivo Video Post Processor
Color space conversion
Chroma subsampling format conversion
Horizontal and vertical scaling
Gamma correction
Advanced vector adaptive per-pixel de-interlacing
De-blocking and noise reduction filtering
Detail enhancement
Inverse telecine (2:2 and 3:2 pull-down correction)
Bad edit correction
Two independent display controllers
Drive two displays simultaneously with independent resolutions, refresh rates, color controls and video overlays for each display
Full 30-bit display processing
Programmable piecewise linear gamma correction, color correction, and color space conversion
Spatial/temporal dithering provides 30-bit color quality on 24-bit and 18-bit displays
High quality pre- and post-scaling engines, with underscan support for all display outputs
Content-adaptive de-flicker filtering for interlaced displays
Fast, glitch-free mode switching
Hardware cursor
Two integrated dual-link DVI display outputs
Each supports 18-, 24-, and 30-bit digital displays at all resolutions up to 1920x1200 (single-link DVI) or 2560x1600 (dual-link DVI)2

Откуда?

да !!Вплоть до четвертой модели шейдеров поддерживает!!