Graphics Cards Guide

ATI Radeon HD 4870 X2 2GB DDR5 (Reference Card) review

ATI Radeon HD 4870 X2 2GB GDDR5 - Two Heads are Better than One

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The Return of the Twin Engines

The Return of the Twin Engines

Not too long ago, we tested ATI's latest flagship GPU, the HD 4870 512MB GDDR5, and remarked that "the best has yet to come". Well, "the best" has finally arrived in our labs. That's right folks; we're talking about the R700, otherwise known as the HD 4870 X2 that combines dual RV770 GPUs on one PCB.

If you haven't already noticed, ATI is pursuing a different strategy when it comes to graphics for the enthusiast market. Similar to Intel, who is pursuing multi-core processors for the future, ATI is focusing their energies on multi-GPU graphics cards. The main advantage of doing this is that it cuts development costs and time, because they no longer have to develop different GPUs of different market segments. Instead, now all ATI has to do is concentrate on a really solid mid-range GPU, and then combine two of them to form a high-end card. The dual-GPU HD 4870 X2, then, is the fruition of ATI's new strategy and efforts (just like they had done earlier with the Radeon HD 3870 X2). Judging from our evaluation of the HD 4870 and HD 4850 series, this strategy seems to be paying dividends.

For the uninitiated, there are several advantages to sticking two GPU cores onto a single card. First of all, you save an expansion slot (or two actually), and secondly, it is also far easier to install. More importantly, this card will not require you to have a motherboard that is CrossFire compatible. But for those who do have a CrossFire friendly motherboard and have enough dough to spare, quad-CrossFire beckons with a pair of Radeon HD 4870 X2 graphics cards!

ATI tells us that the HD 4870 X2 is meant to be a more powerful solution than NVIDIA's current flagship, the single-GPU GTX 280. So let's see how it stacks up, shall we?

ATI Radeon HD 4870 X2 and Competitive Comparison Cards
Model Radeon HD 4870 X2 2GB Radeon HD 4870 512MB Radeon HD 4850 512MB NVIDIA GTX�280 1GB NVIDIA GTX 260 896MB ATI Radeon HD 3870 X2 1GB
Core Code R700 (RV770 x 2) RV770 RV770 GT200 GT200 R680 (RV670 x 2)
Transistor Count 1912 million 956 million 956 million 1400 million 1400 million 1332 million
Manufacturing Process 55nm 55nm 55nm 65nm 65nm 55nm
Core Clock 750MHz 750MHz 625MHz 602MHz 576MHz 825MHz
Stream Processors 320 Processors (1600 Stream processing units) 160 Processors (800 Stream processing units) 160 Processors (800 Stream processing units) 240 Stream Processors 192 Stream Processors 128 Processors (640 Stream processing units)
Stream Processor Clock 750MHz 750MHz 625MHz 1296MHz 1242MHz 825MHz
Texture Mapping Units (TMU) or Texture Filtering (TF) units 80 40 40 80 64 32
Raster Operator units (ROP) 32 16 16 32 28 32
Memory Clock 3600MHz GDDR5 3600MHz GDDR5 2000MHz GDDR3 2214MHz GDDR3 1998MHz GDDR3 1800MHz GDDR3
DDR Memory Bus Width 256-bit 256-bit 256-bit 512-bit 448-bit 256-bit
Memory Bandwidth 230GB/s 115.2GB/s 64GB/s 141.7GB/s 111.9GB/s 115.2GB/s
PCI Express Interface PCIe ver 2.0 x16 PCIe ver 2.0 x16 PCIe ver 2.0 x16 PCIe ver 2.0 x16 PCIe ver 2.0 x16 PCIe ver 2.0 x16
Molex Power Connectors 6-pin, 8-pin 2 x 6-pin 6-pin 6-pin, 8-pin 2 x 6-pin 6-pin, 8-pin
Multi GPU Technology Yes (CrossFireX) Yes (CrossFireX) Yes (CrossFireX) Yes (SLI) Yes (SLI) Yes (CrossFireX)
DVI Output Support 2 x Dual-Link 2 x Dual-Link 2 x Dual-Link 2 x Dual-Link 2 x Dual-Link 2 x Dual-Link
HDCP Output Support Yes Yes Yes Yes Yes Yes
Street Price US$549 US$299 US$199 US$499 US$299 ~US$250 - 280