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Boarding up
The focus of our attention today, though, is the Radeon HD 5870. This is AMD's fastest single-GPU implementation of Cypress, with all 1600 SPs enabled and cranking away at 850 MHz. The card has a gigabyte of GDDR5 memory onboard clocked at 1200 MHz, for a 4.8 Gbps data rate. Also, it's rather long. Have a look:


Radeon HD 5870 (left) next to 4890 (right)


Twin dual-link DVI connectors, along with HDMI, DisplayPort, and CrossFire connections


Thankfully, two six-pin power plugs will suffice


The bare card

The 5870 card's PCB is 10.5" long, an inch longer than the 4980 before it and the same size as a GeForce GTX 260 or a Radeon HD 4870 X2. However, that fancy cooler shroud extends to roughly 10 7/8", which means the 5870 might have fit problems in more compact PC cases. You'll want to measure before assuming this beast will fit into your mid-tower enclosure, folks.

Despite its iffy dimensions, AMD has clearly paid attention to detail in the card's design. The multi-colored, injection-molded cooler shroud with Bat-inspired intake vents is just part of that. Dave Baumann, the 5870's product manager, told us the firm had listened to users' worries about high idle temperatures in the 4800 series and adjusted the 5870's cooling accordingly. The 5870 should also have lower fan RPMs than its predecessor, and the use of a different bearing in the blower should produce a lower-pitched sound that's less obtrusive in operation. AMD has built in hardware detection of voltage regulator temperatures, as well, to avoid the overheating problems caused by "an application that amounted to a power virus" that caused some problems on RV770 and other cards. (FurMark, anyone?)

The single biggest improvement from the last generation, though, is in power consumption. The 5870's peak power draw is rated at 188W, up a bit from the 4870's 160W TDP. But idle power draw on the 5870 is rated at an impressively low 27W, down precipitously from the 90W rating of the 4870. Much of the improvement comes from Cypress's ability to put its GDDR5 memory into a low-power state, something the 4870's first-gen GDDR5 interface couldn't do. Additionally, the second 5870 board in CrossFire multi-GPU config can go even lower, dropping into an ultra-low power state just below 20W.

AMD says the plan is for Radeon HD 5870 cards to be available for purchase today at a price of $379. Nvidia appears to have cut prices preemptively in anticipation of the 5870's launch, too, at least selectively. This GeForce GTX 285 is down to $295.99 after rebate at Newegg, and this MSI GeForce GTX 295 is reduced to $469.99 with free shipping, as I write.


The Radeon HD 5850. Source: AMD.

In all likelihood, the GTX 285 will find closer competition in the form of the Radeon HD 5850, the second Cypress-based product, due next week. The 5850 will have two of its SIMD arrays and texture units disabled, leading to a total of 1440 SPs and 72 texels per clock of filtering capacity. Also, clock speeds will be down, with the GPU at 725 MHz and the GDDR5 memory at 1 GHz or 4 Gbps. The 5850 will have the same suite of display outputs and CrossFire multi-GPU capabilities as the 5870, though, and will come with a visibly shorter PCB. AMD expects these boards to be available next week, most likely on Monday, for $259.