Even as we wrote about ATI's dual GPU flagship product, the Radeon HD 3870 X2 early this year, not only did we know that it was just a matter of time before NVIDIA countered with its own equivalent, the name and general details of this NVIDIA product were already not much of a secret with enthusiasts. Initially, we were told to expect it to be released sometime in February but it got delayed (leading to the usual rumors). However, we were quickly placated by the debut of the mainstream GeForce 9600 GT. Now, with the excitement of that launch taking a dive, it was time to up the tempo again for all things NVIDIA and the company finally sent us a reference GeForce 9800 GX2, the much anticipated dual GPU riposte to the Radeon HD 3870 X2 late last week.
So what exactly is found within the sleek black exterior of this new card? Well, it's no surprise: there are two G92 cores onboard, each on its own PCB and with its own cluster of 512MB frame buffer (hence a total of 1GB). They are linked internally in SLI and should be seen as a single entity by the system, regardless whether it is an SLI compatible motherboard or not. In short, the new GeForce 9800 GX2 does not just follow the naming convention of the previous dual GPU graphics card from NVIDIA, the GeForce 7950 GX2, it also duplicates the dual PCB design and 'internal' SLI, though there has been some progress obviously.
While ATI has managed to squeeze two RV670 cores onto the same PCB for its Radeon HD 3870 X2, the reference cooler cannot cool both cores with the same efficacy. Therefore, NVIDIA tried another approach with the GeForce 9800 GX2. That is to have a single cooler for both GPUs. Hence, unlike the GeForce 7950 GX2, the 9800 update has both cores facing each other, with the heatsink sandwiched in the middle instead of separately attached to its own core. This is completed by having a large metallic shroud encasing the whole structure and giving it both solidity and a sleek finished appearance. NVIDIA obviously felt that this unified design would reduce some of the worries about heat that have been raised ever since enthusiasts found out that the GeForce 9800 GX2 involved two rather hot GPUs in the form of the G92.
Besides the engineering involved to combine two G92 cores into a seemingly single card, the internals of the GeForce 9800 GX2 are not that different from the original GeForce 8800 GT 512MB, except that the newcomer has a full array of 128 stream processors enabled for each core. The core clock is at 600MHz, with the aggregated 256 stream processors operating at 1500MHz. So far, very GeForce 8800 GT/GTS-like. NVIDIA however is keen to emphasize on the higher 2000MHz DDR memory clock on the GX2 as a vote of confidence for the cooling onboard the card. Unlike the Radeon HD 3870 X2 that had slower memory than the single core version, the GeForce 9800 GX2 has higher memory clocks.
With such specifications, the GeForce 9800 GX2 looks to be the new high-end enthusiast offering from NVIDIA, replacing the expensive GeForce 8800 Ultra. Below, we show the important specifications of the various high-end models from NVIDIA and its dual GPU rival from ATI:
|Model||NVIDIA GeForce 9800 GX2 1GB||ATI Radeon HD 3870 X2 1GB||NVIDIA GeForce 8800 Ultra 768MB||NVIDIA GeForce 8800 GTS 512MB||NVIDIA GeForce 8800 GT 512MB|
|Core Code||G92 x 2||R680 (RV670 x 2)||G80||G92||G92|
|Transistor Count||1508 million||1332 million||681 million||754 million||754 million|
|Stream Processors||256 Stream Processors||128 Shader units (640 stream processing units)||128 Stream Processors||128 Stream Processors||112 Stream Processors|
|Stream Processor Clock||1500MHz||825MHz||1500MHz||1625MHz||1500MHz|
|Texture Mapping Units (TMU) or Texture Filtering (TF) units||128||32||64||64||56|
|Raster Operator units (ROP)||48||32||24||24||16|
|Memory Clock||2000MHz GDDR3||1800MHz GDDR3||2160MHz GDDR3||1940MHz GDDR3||1800MHz GDDR3|
|DDR Memory Bus||256-bit||256-bit||384-bit||256-bit||256-bit|
|Ring Bus Memory Controller||NIL||512-bit||NIL||NIL||NIL|
|PCI Express Interface||PCIe ver 2.0 x16||PCIe ver 2.0 x16||PCIe ver 1.0 x 16||PCIe ver 2.0 x16||PCIe ver 2.0 x16|
|Molex Power Connectors||Yes||Yes||Yes||Yes||Yes|
|Multi GPU Technology||Yes (SLI)||Yes (CrossFireX)||Yes (SLI)||Yes (SLI)||Yes (SLI)|
|DVI Output Support||2 x Dual-Link||2 x Dual-Link||2 x Dual-Link||2 x Dual-Link||2 x Dual-Link|
|HDCP Output Cable?||Yes||Yes||Yes||Yes||Yes|
|Street Price||US$599 - 649||US$449||US$649||~US$244 - 329||~US$199 - 249|