ATI Radeon 5850 Performance Preview

Last week ATI launched the world’s first DirectX 11 GPU, the Radeon HD 5870. Packing 1600 stream processors, 80 texture units, and 32 ROPS, the 5870 boasts twice the shading and texturing horsepower of Radeon 4800 (not to mention twice the hardware-based resolve units for AA) all inside its 27% larger 334 mm2 frame.

With approximately 2.15 billion transistors, it’s the most complex chip ever created to grace the inside of your PC. It also holds the title of the fastest GPU money can buy today. This is a distinction previously held by NVIDIA’s GeForce GTX 285.

But not everyone can afford to shell out $379 for the Radeon HD 5870. This is a premium of 26% over the launch price of the Radeon 4870 last year. Of course, given the Radeon 5870’s larger die and superior performance, we think ATI’s new asking price for the 5870 is fair and reasonable, but given the state of today’s economy where hardware prices have fallen dramatically, consumers are now out to get the most bang from their buck.

Therefore ATI has also concocted the Radeon HD 5850. Built on the same RV870 architecture as the 5870, the 5850 gives you 90% of the shading and texturing units as the 5870 for $120 less.

Now because it runs at slower clock speeds also, that doesn’t mean it delivers 90% of the 5870’s performance, but it is built to give you most of the performance in a smaller, more case-friendly package that also consumes less power and generates very little noise. ATI pitches it as the perfect card for the performance-minded gamer on a budget who may have been contemplating a GeForce GTX 285 purchase.

Here are the raw specs on ATI’s Radeon 5850:

Radeon 5850 Specifications

TeraScale 2 Unified Processing Architecture

1440 Stream Processing Units

72 Texture Units

128 Z/Stencil ROP Units

32 Color ROP Units

GDDR5 interface with 128.0 GB/sec of memory bandwidth

PCI Express 2.1 x16 bus interface

DirectX 11 support

Shader Model 5.0

DirectCompute 11

Programmable hardware tessellation unit

Accelerated multi-threading

HDR texture compression

Order-independent transparency

OpenGL 3.2 support

Image quality enhancement technology

Up to 24x multi-sample and super-sample anti-aliasing modes

Adaptive anti-aliasing

16x angle independent anisotropic texture filtering

128-bit floating point HDR rendering

ATI Eyefinity multi-display technology

Three independent display controllers drive three displays simultaneously with independent resolutions, refresh rates, color controls, and video overlays

Display grouping: Combine multiple displays to behave like a single large display

ATI Stream acceleration technology

OpenCL 1.0 compliant

DirectCompute 11

Double precision floating point processing support

Accelerated video encoding, transcoding, and upscaling

ATI CrossFireX™ multi-GPU technology

Dual, triple, and quad GPU scaling

Dual-channel bridge interconnect

ATI Avivo HD Video & Display technology

UVD 2 dedicated video playback accelerator

Advanced post-processing and scaling8

Dynamic contrast enhancement and color correction

Brighter whites processing (blue stretch)

Independent video gamma control

Dynamic video range control

Support for H.264, VC-1, and MPEG-2

Dual-stream 1080p playback support

DXVA 1.0 & 2.0 support

Integrated dual-link DVI output with HDCP (Max resolution: 2560x1600)

Integrated DisplayPort output (Max resolution: 2560x1600)

Integrated HDMI 1.3 output with Deep Color, xvYCC wide gamut support, and high bit-rate audio (Max resolution: 1920x1200)

Integrated VGA output (Max resolution: 2048x1536)

Integrated HD audio controller

Output protected high bit rate 7.1 channel surround sound over HDMI with no additional cables required

Supports AC-3, AAC, Dolby TrueHD and DTS Master Audio formats

Speeds and feeds

Engine clock speed: 725 MHz

Processing power (single precision): 2.09 TeraFLOPS

Processing power (double precision): 418 GigaFLOPS

Polygon throughput: 725M polygons/sec

Data fetch rate (32-bit): 209 billion fetches/sec

Texel fill rate (bilinear filtered): 52.2 Gigatexels/sec

Pixel fill rate: 23.2 Gigapixels/sec

Anti-aliased pixel fill rate: 92.8 Gigasamples/sec

Memory clock speed: 1 GHz

Memory data rate: 4.0 Gbps

Memory bandwidth: 128 GB/sec

Maximum board power: 151 Watts

Idle board power: 27 Watts

Notes

For the Radeon 5850 ATI takes the same RV870 chip used in the Radeon 5870 and disables two SIMD units, dropping the total number of active SIMD units to 18. If you recall, each SIMD unit contains 80 stream processors and 1 texture unit (4 effective), so ultimately ATI disables 160 stream processors and 2 texture units (8 effective) for the Radeon 5850.

Besides turning off some of the chip’s functionality, ATI also drops the clocks down to 725MHz for the graphics core and 1.0GHz for the memory. With fewer shaders and slower clocks, ATI is able to source cheaper GDDR5 memory modules and a smaller PCB with less power circuitry and smaller cooling is needed. This helps to keep the Radeon 5850’s price and power consumption down in comparison to the 5870. We’ll be taking a closer look at the 5850 board itself on the next page.

5870 up top, followed by the 5850 in the middle and GTX 285

5870 and 5850

The following chart sums up how the Radeon 5850 stacks up against the Radeon 4870, 5870 and NVIDIA’s GeForce GTX 285:

High-end GPU Comparison
GPU	Radeon HD 4870	Radeon HD 5850	Radeon HD 5870	GeForce GTX 285
Manufacturing Process	55-nm	40-nm	40-nm	55-nm
Graphics Core Clock Speed	750MHz	725MHz	850MHz	648MHz
Stream Processor Clock Speed	750MHz	725MHz	850MHz	1,476MHz
# of Stream Processors	800	1440	1600	240
Memory Clock Speed	900MHz (3.6 Gbps data rate)	1000MHz (4.0 Gbps data rate)	1200MHz (4.8 Gbps data rate)	1,242MHz (2,484MHz effective)
Memory Interface	256-bit	256-bit	256-bit	512-bit
Memory Bandwidth	115.2 GB/sec	128 GB/sec	153.6 GB/sec	159GB/sec
Memory Size	512MB/1GB	1GB	1GB	1GB/2GB
ROPs	16	32	32	32
Texture Filtering Units	40	72	80	80
Texture Filtering Rate	30.0 GigaTexels/sec	52.2 GigaTexels/sec	68 GigaTexels/sec	51.8 GigaTexels/sec
Pixel Fill Rate	12 GigaPixels/sec	23.2 Gigapixels/sec	27.2 Gigapixels/sec	21.4 GigaPixels/sec
Power Connectors	2x6-pin	2x6-pin	2x6-pin	2x6-pin
Max Board Power	160W	151W	188W	183W
Price	$144.99-$229.99	$259	$379	$325.99-$397.99