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Review: Sapphire Radeon HD 5870 in CrossFireX: say hello to our little friends

by Parm Mann on 23 September 2009, 08:58 3.8

Tags: Radeon HD 5870 1,024MB, AMD (NYSE:AMD), Sapphire

Quick Link: HEXUS.net/qat4c

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Take Two

Before we get to benchmarks, here's how a pair of 1GB Radeon HD 5870s configured in CrossFireX stack up to the rest of AMD's high-end range. Knowing that one Radeon HD 5870 is the fastest single-GPU card currently on offer, the raw power of two side-by-side is indisputable. Here are the figures:

Graphics cards Radeon HD 5870
1,024MB
(x2 in CrossFireX)
Radeon HD 5870
1,024MB

Radeon HD 5850
1,024MB

Radeon HD 4870 X2
2,048MB
Radeon HD 4850 X2
2,048MB
Radeon HD 4890
1,024MB
Radeon HD 4870
512MB
Radeon HD 4850
512MB
PCIe PCIe 2.0
GPU(s) clock 850MHz 850MHz 725MHz 750MHz 625MHz 850MHz 750MHz 625MHz
Shader clock 850MHz 850MHz 725MHz 750MHz 625MHz 850MHz 750MHz 625MHz
Memory clock (effective) 4,800MHz 4,800MHz 4,000MHz 3,600MHz 1,986MHz 3,900MHz 3,600MHz 1,986MHz
Memory interface and size 512-bit (2x 256-bit), 2,048MB, GDDR5 256-bit, 1,024MB, GDDR5 256-bit, 1,024MB, GDDR5 512-bit (2x 256-bit), 2,048MB, GDDR5 512-bit (2x 256-bit), 2,048MB, GDDR3 256-bit, 1,024MB, GDDR5 256-bit, 512MB, GDDR5 256-bit, 512MB, GDDR3
Memory bandwidth 307.2GB/s 153.6GB/s 128GB/s
230.4GB/s
127.1GB/s
124.8GB/s
115.2GB/s 63.5GB/s
Manufacturing process TSMC, 40nm TSMC, 40nm TSMC, 40nm TSMC, 55nm TSMC, 55nm TSMC, 55nm TSMC, 55nm TSMC, 55nm
DirectX/ Shader Model DX11, 5.0 DX11, 5.0 DX11, 5.0 DX10.1, 4.1 DX10.1, 4.1 DX10.1, 4.1 DX10.1, 4.1 DX10.1, 4.1
Vertex, fragment, geometry shading (shared) 3,200 FP32 scalar ALUs, MADD dual-issue (unified) 1,600 FP32 scalar ALUs, MADD dual-issue (unified) 1,440 FP32 scalar ALUs, MADD dual-issue (unified) 1,600 FP32 scalar ALUs, MADD dual-issue (unified) 1,600 FP32 scalar ALUs, MADD dual-issue (unified) 800 FP32 scalar ALUs, MADD dual-issue (unified) 800 FP32 scalar ALUs, MADD dual-issue (unified) 800 FP32 scalar ALUs, MADD dual-issue (unified)
Data sampling and filtering 160ppc address and 160ppc bilinear INT8/80ppc FP16 filtering, max 16xAF 80ppc address and 80ppc bilinear INT8/40ppc FP16 filtering, max 16xAF 72ppc address and 72ppc bilinear INT8/36ppc FP16 filtering, max 16xAF 80ppc address and 80ppc bilinear INT8/40ppc FP16 filtering, max 16xAF 80ppc address and 80ppc bilinear INT8/40ppc FP16 filtering, max 16xAF 40ppc address and 40ppc bilinear INT8/20ppc FP16 filtering, max 16xAF 40ppc address and 40ppc bilinear INT8/20ppc FP16 filtering, max 16xAF 40ppc address and 40ppc bilinear INT8/ 20ppc FP16 filtering, max 16xAF
ROPs 64 32 32 32 32 16 16 16
Peak GFLOPS 5,440
2,720
2,160 2,400 2,000 1,360 1,200 1,000
Peak fillrate Gpixels/s 54.4
27.2
23.2
24 20 13.6 12 10
Peak Gtexel/s (bilinear) 136
68
52.2
60 50 34 30 25
Peak Gtexel/s (FP16, bilinear) 68
34
26.1 30 25 17 15 12.5
Connectors (native) 2x dual-link DVI
HDMI, DisplayPort, HDTV-out, Eyefinity
2x dual-link DVI
HDMI, DisplayPort, HDTV-out, Eyefinity
2x dual-link DVI
HDMI, DisplayPort, HDTV-out
2x dual-link DVI
HDMI, DisplayPort, HDTV-out
2x dual-link DVI
HDMI, DisplayPort, HDTV-out
2x dual-link DVI
HDMI, DisplayPort, HDTV-out
2x dual-link DVI
HDMI, DisplayPort, HDTV-out
2x dual-link DVI
HDMI, DisplayPort, HDTV-out
Current price £598 (2x £299)
£299
£220
£250
£200
£125
£95 £80

The numbers are almost preposterous. Doubling up on cards, as expected, propels the statistics - a pair of Radeon HD 5870s in CrossFireX will provide 64 ROPs and 160 texture filtering units, creating a mind-boggling bilinear filtering capacity of 136Gtexels/s.

Common sense will you tell that performance will be exceptional, but there are a few provisos to be aware of. First and foremost, users need to be wary of the foibles of multi-GPU usage - scaling is rarely linear, and your mileage could vary depending on software support. Secondly, you'll need a board supporting ATI CrossFireX technology, and last but not least, there's the small matter of the initial outlay. At launch, picking up two Radeon HD 5870s could set you back in the region of £600.

Sounds scary, but here's a duo we prepared earlier:

We're about to get into benchmark territory, but for those wanting to know more about the inner workings of AMD's ATI Radeon HD 5870 GPU - and, indeed, Microsoft's upcoming DirectX 11 API - we encourage you to take a look at our in-depth analysis by clicking here. Already clued up? Move straight on.