Sapphire Vapor-X HD 4870 2G (Radeon HD 4870 2,048 MB)
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Sapphire's Vapor-X cooler is quite effective. While other cards are equipped with thick, heavy, copper heatsinks and fans, the entire cooling assembly on this Radeon HD 4870 model measures only 3.54"x3.54"x1.18" (90x90x30 mm). It’s built on a flat copper plate with numerous aluminum cooling fins attached. The assembly looks like a cut-down version of the coolers that Intel or AMD bundle in their retail CPU boxes.
Inside the cooler, you’ll find an evacuated chamber, where water functions as a cooling medium. The water removes heat from the chips, and the vacuum promotes efficient heat exchange with the much cooler ambient temperature inside the case. This kind of phase-change cooling depends on evaporation at the heat source, when the heatsink makes contact with the chips and condensation at the outer reaches of the heatpipes, where thermal energy maintains constant circulation. Capillary action also aids circulation of condensed liquid back to the hot surfaces on their return trip.
Nevertheless, temperatures in this unit don’t differ much from the ATI reference design. In idle 2D mode, we got readings of 58° C/136.4° F instead of 60° C/140° F. Under heavy load, those tables turn a bit, with the Sapphire card reading 76° C/168.8° F and the reference card 74° C/165.2° F. The real difference in this cooling solution stands out in our noise measurements. At 2D idle mode, the Sapphire card is whisper-quiet at 36 dB(A), while it climbs only to 38.2 dB(A) under heavy load (by contrast, the ATI reference model ratchets up to 49.8 dB(A)).
In this design, the card also vents its exhaust through slits in the external connector edge. The vapor circulates down to the bottom of card to a secondary heatsink that cools the voltage regulator and various heavy-duty condensers. Because this card comes equipped with 2 GB of graphics RAM, you’ll also find heatsinks on its back side to cool those chips as well. Memory chips on the front are not cooled, however, because they’re not beneath the primary heatsink.
In overall performance, the Sapphire card falls between the overclocked HIS IceQ4+ and the Radeon HD 4870 reference card. The 2 GB of graphic RAM boosts frame rates in Fallout 3 by up to 7 FPS, and in Far Cry 2 frame rates at 1920x1200 resolution with 8x AA leap from a paltry 11.1 FPS (from the 512 MB reference card) to a fairly fluid 30.4 FPS. There isn’t much difference in other benchmarks, though. This card also clocks down to 500 MHz in 2D idle mode.
The Vapor-X card requires two six-pin PCIe connectors, so you’ll find two such adapter cables in the retail box. Its souped-up Radeon HD 4870 supports DirectX 10.1 with Shader 4.1. Other bundled goodies include the PowerDVD bundle, 3DMark Vantage Advanced Edition, Cyberlink DVD Suite v5 with applications, an ATI demo, a driver CD, and a CrossFire connector. Adapters aren’t really needed, because external ports include analog D-sub mini, HDMI, and DVI.