|Sapphire Radeon HD 4870 X2 Atomic ST-6026|
|Reviews - Featured Reviews: Video Cards|
|Written by Olin Coles|
|Thursday, 18 December 2008|
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First Look: Sapphire Atomic
When I first held Sapphire's Radeon HD 4870 X2 several months back, it seems like the card was abnormally long and heavy. Perhaps the problem with the Radeon HD 4870 X2 design was that it really is abnormally long and the thermal management components made it very heavy. Sapphire improves cooling performance while reducing overall dimensions with their Radeon HD 4870 X2 Atomic. The single board layout of the Sapphire Radeon HD 4870 X2 Atomic with its single slot cooler brings the fastest solution yet available to performance users with only a single PCI-Express expansion slot. This is better than the the mess two Radeon HD 4870's can make inside a cramped computer case.
The Sapphire Radeon HD 4870 X2 Atomic comprises two complete HD 4870 graphics systems on a single PCI-Express card connected by an integrated PEX 8647 PCI-Express 2.0 switch from PLX Technology, which adds features like Dual Cast and Read Pacing over previous generations. Each GPU has 800 stream processors and is equipped with 1MB of GDDR5 memory, making a total of 1600 stream processors and 2GB of memory on-board. Two Dual Link DVI outputs are provided as well as TV-Out. 3D applications such as games use both on-board GPU's together in CrossFire mode to deliver a single accelerated output on the Primary display.
Liquid coolant in the Sapphire Radeon HD 4870 X2 Atomic is circulated through the graphics card cooler and a chassis mounted Asetek radiator by a pump assembly which fixes onto the standard system CPU mountings (both AMD AM2 and Intel LGA775 mounts supplied). The graphics cooler, CPU cooler and radiator are connected in a closed loop by high quality flexible yet tough Teflon tubing and attachéd to each module with interference fit barbed joints that are sealed for life. This arrangement is easy to install, and efficiently cools the system CPU even in enthusiast systems where it is common to raise CPU speeds. The pump and sealed joints have been independently tested to 50,000 hours MTBF.
While the Sapphire HD 4870 X2 Atomic utilizes a full-length reference AMD/ATI printed circuit board (PCB), the custom water-cooling unit keeps the twin AMD RV770 GPUs well below the reference operating specifications. A custom-designed water block unit seals itself to the GPU and surface components very well, and the single expansion card slot requirement gives the Radeon HD 4870 X2 a more functional design.
Cooling was one of the weakest point of contention for many enthusiasts when discussing the original 4870 X2 design; but the topic is put to rest with Sapphire's unique liquid-based thermal management system. With two AMD RV770 GPUs working side-by-side inside the HD 4870 X2, you can never really have too much cooling. Each GPU has a 256 mm² footprint, and although they are made using the 55 nm process the collection of 956 million transistors has been proven to raise the room temperature a few degrees if not kept in check.
Air flow through the radiator is provided by a low noise 120mm 7-blade fan which delivers up to 60 cfm at full speed and is illuminated by blue LEDs. The fan and radiator can be mounted on the rear panel or in the top of the PC enclosure. The fan can be connected directly to the system power supply, to a motherboard connector, or to a fan speed controller which allows user controlled fan speeds and even lower noise when the PC is used for less demanding applications. Note that the ST-6026 system has only one fan and one pump cooling both CPU and dual graphics, considerably reducing overall system noise.
After taking a good look over the Atomic ST-6026 kit, it becomes clear that this is a premium product designed for hardcore hardware enthusiasts with a higher understanding of computer components and liquid cooling. I wasn't totally thrilled with the CPU cooling unit, which only includes AM2 and LGA775 mounting kits, so it could not be attachéd to the Intel Core i7-920 Processor running on the LGA1366-based Gigabyte GA-EX58-EXTREME X58 Motherboard we use for testing. Since the pump unit (built into the CPU water block) is no larger than a tennis ball, it can be positioned anywhere else inside the computer case or rest against the PCB on the Atomic 4870 X2 video card. With a little extra engineering, I think that Sapphire could have turned these components into a multi-purpose cooler for warm-running Northbridge chipsets.
In our next section we detail our methodology for testing video cards. Following this we offer a cadre of benchmarks to show where the Sapphire Radeon HD 4870 X2 Atomic ST-6026 stands against the Radeon 4870, GeForce 9800 GX2, a pair of Radeon HD 4850's in CrossFireX, along with a GTX 260 and GTX 280 put in for good measure... so please read on!