nVidia 9800 GX2

Introduction

Leaks, rumors and controversy concerning Nvidia's multi-GPU configurations abound. The debut of the new 9800 GX2 provides a great opportunity to address and discuss these concerns. Join us as we preview Nvidia's latest multi-GPU offering: the 9800 GX2.

Setup and Changes

With the general trend towards widescreen HDTV gaming, we've decided up the ante to answer the question of "How will games perform on an HDTV?", as well as providing a more GPU limited experience with tests run at a 1920x1080 resolution. The 9800 GX2 comes equipped with a direct HDMI adaptor so many users may find themselves running this resolution on their HDTVs.  We used an Olevia 27" Widescreen HDTV for all of the testing in this review.

HDMI

• Test Setup
  
  E6300 @ 3.2 Ghz
  XFX Nforce 790I @ 1828 FSB
  2 Gigs Crucial Ballistic DDR3 clocked @ 2000 MHz
  Forceware 174.45
  Windows Vista 64 bit
  
  
• Introducing the NVIDIA 9800 GX2
  
  Core Clock: 600 MHz
  Stream Processors: 256 (128 per GPU)
  Stream Processor Clocks: 1.5 GHz
  Texture Address Units: 128 (64 per GPU)
  Total Memory: 1 Gigabyte ((512 per GPU) 512 Megabytes available frame buffer))
  Bus Width: 512 (256 per GPU)
  Memory Clocks: 1 GHz (2 GHZ DDR)
  
  

PureVideo HD

The G92 architecture has several improvements to PureVideo which provides better acceleration and lower CPU utilization. These improvements can be seen on 8800 GT, 8600 GT, and 8800 GTS 512 cards that currently occupy the market as well. The 8800 GTX, 8800 Ultra and 8800 GTS 640 do not support these enhanced GPU accelerated codecs. The 9800 GX2 also supports "Dual Stream" which allows for the most advanced forms of HD processing to occur on the GPU level such as "Picture in a picture"

Dual Stream

PureVideo

Power

The 9800 GX2 requires a 580 watt PSU for normal operation, which assumes you're running a Quad core processor with other high end components. For those planning to operate two 9800 GX2 cards, an 850 power supply is recommended. The 9800 GX2 is also the first card from Nvidia to require an 8 pin power connector: this is not an optional requirement. The 9800 GX2 will not function with two 6 pin power connectors connected to it; you must connect one 8 pin and one 6 pin for normal operation.  Nvidia is working with both graphics card manufacturers and power supply vendors to ensure compatibility and offer adapters where necessary.  See Nvidia's list of Compatible Power Supplies for more information.

We've selected games based on their ability to stress the GPU, making them perfect to flex the muscles of the 9800 GX2.  Lets see how it measures up.

Oblivion

Performance Thoughts: It's amazing how quickly this title turned from one of the most GPU limited titles of its time to CPU limited on today's platforms, allowing us to enabled transparency supersampling in all tests to increase load. The 9800 GX2 performs fairly well in these tests, remaining competitive with the 8800 GTX SLI configuration with 16xAA enabled while still slightly CPU limited. At these settings, Tri SLI 8800 GTX becomes completely CPU limited. Turning on 16xQ changes the situation, with to the increased bandwidth requirements the 9800 GX2 coming out every so slightly behind the SLI 8800 GTX configuration. The 9800 GX2 consistently outperforms the 8800 GT SLI configuration due to its superior bandwidth, shader performance, and texturing capabilities.

Unreal Tournament 3

Performance Thoughts: Unreal Tournament 3 is the latest shooter from Epic games, with its strong ties to shader performance readily seen in these tests. The game appears to benefit nicely from the G92 architecture as well, with the 9800 GX2 holding a decent advantage over the 8800 GTX SLI with 16xCSAA, likely due to the increased shader performance available. Unfortunately we were unable to test the 16xQ modes on the 512 meg cards due to the game crashing with driver not responding errors when enabled at 1920x1080; we believe this to be a memory management error and have reported the problem to Nvidia. The 9800 GX2 was again able to consistently outperform the 8800 GT SLI setup due to superior shader, texturing, and bandwidth.

Notes: As many are aware, Unreal Tournament 3 has a frame smoothing option typically set to 62 to control erratic frame rate distributions. During the tests, we adjusted it to a maximum of 75, which affects both Max and Avg framerates slightly. None of the configurations tested were capable of offering 75 FPS or higher with any consistency at the settings tested so we believe these results to be very fair and balanced.

Serious Sam 2

Performance Thoughts: Like the Oblivion tests, we reached CPU limitations before hitting the GPU limits several times; however, SS2 never became entirely CPU limited at 16xCSAA, and the 9800 GX2 and 8800 GTX SLI took swings at each but ultimately offer equivalent performance in these tests. Running 16xQ modes shifts the bottleneck squarely on the GPU, with the bandwidth restrictions of the 9800 GX2 placing it slightly behind the 8800 GTX SLI setup but ahead of the 8800 GT SLI by a decent margin.

Bioshock Performance

Performance Thoughts: Bioshock, one of the big games released in 2007, offers a demanding test for this roundup. We used DirectX 9.0 testing for anti aliasing support, and in these tests the 8800 GTX and 9800 GX2 run neck and neck performance wise, offering equivalent performance at 16xCSAA. With 16xQ enabled the 8800 GTX SLI control a slight lead, while once again the 9800 GX2's superior rendering capabilities allow it to come ahead of the 8800 GT SLI configuration.

Crysis Performance

Performance Thoughts: Crysis is a title that has left many systems crying for mama this year with its insane performance requirements. Few have been able to run this game anywhere close to high end settings, and even this test system had to make some setting sacrifices to ensure the game was playable. Choosing primarily high settings, we lowered the shadow volumes to medium.  We also skipped the high end AA comparison, sticking instead with 2x and 4xAA performance options. Under these tests conditions the 9800 GX2 held a decent advantage over the 8800 GTX SLI due to its superior shader performance. The 8800 GT SLI put out some good numbers with its strong shader performance (comparable to 8800 GTX SLI) but was unable to keep up with the 9800 GX2.

Notes: This was a case where the title became too much for 512 meg cards to handle, so all tests were concluded with shadow volumes at medium. With the shadow volumes set to high, the game slowed down to 5 FPS on both the 8800 GT and 9800 GX2, with the 8800 GTX slightly better at around 17 FPS. This is one of those scenarios where the 8800 GTX's memory allowed it a considerable advantage.

We've approached this review a little differently, so will do our best to hit it from every angle.  We'll look at the HDTV gaming experience, followed with some comparisons against the competing SLI options on the market, and finish up with our overall impressions on the new 9800 GX2.

HDTV Gaming on Modern Hardware:

While the prominent display resolutions on the market remain 1280x1024 and 1680x1050, the prices of HDTV displays are dropping in price and modern users increasingly have the option of simply connecting their computers directly into their LCD/Plasma HDTV sets. Users who intend on doing this will definitely need a high end display setup, as even a single 8800 GTX is unable to provide a consistent experience at 1920x1080.  We're pleased to report, however, that a single 9800 GX2 is  up to the task. In this case the more graphic power you have the better. What is the point in having an high definition setup if you must consistently compromise on quality?

SLI Comparisons:

• 8800 GTX SLI vs. 9800 GX2
  
  We found the performance of these cards to be mostly a wash. If you currently own a 8800 GTX you should consider upgrading to a second 8800 GTX to obtain similar, and in some cases superior, performance due to the additional frame buffer. The scale tips toward the 9800 GX2 for anyone buying a complete solution today, and these users should avoid the 8800 GTX SLI path. Consider this: a 9800 GX2 consumes a total of 197 watts of power, while dual 8800 GTX cards consume nearly twice that, which results in nearly twice the amount of total heat outputted in your system. The G80 hardware also does not offer the advanced PureVideo engine, limiting its versatility. With the 9800 GX2 aiming to work in any chipset, it simply makes more sense to buy a single 9800 GX2 single card than dual 8800 GTX SLI cards at this time. The only hurdle might be power supplies, but newer power supplies coming onto the market and the adapters being provided this shouldn't be too much of an issue.



• 8800 GT SLI vs. 9800 GX2
  
  This fight is a tougher draw for the 9800 GX2. The 8800 GT cards are cheaper and can be easily SLI'd to provide performance that is usually 10-15% slower than a single 9800 GX2. For future upgradability, however, the 8800 GTs in SLI will not have the QUAD SLI upgrade path offered by dual 9800 GX2 cards, and still offers slightly inferior performance. Power and heat becomes a non-issue here as dual 8800 GT cards have very similar thermal and power characteristics to a single 9800 GX2. Both solutions also offer similar PureVideo functionality. The 9800 GX2 is the faster solution and does offers the luxury of being used on non nForce chipsets for those not wishing to upgrade their motherboard, which certainly impacts the value of this solution for some.



• 8800 Tri SLI vs. 9800 GX2 Quad SLI
  
  With the Quad configurations still in testing, we will refrain from making any direct recommendations regarding this. Rage3D plans to provide a Quad SLI performance preview and configuration guide, giving us an opportunity to measure it against 8800 GTX Tri SLI. Stay Tuned.

Overall Impression:

We were admittedly a bit dubious about a 9800 GX2 when we first heard about it. Likewise, we cannot issue a final verdict until we get a chance to completely test Quad SLI. Clearly this card uses SLI technology and will have similar performance to many of the current SLI configurations. However, being a single card solution gives it the advantage of working with any chipset. We're also impressed with the unique cooling solution, resulting in a card that is quieter than both 8800 GTX SLI and 8800 GT SLI configurations.

The dual PCB design of the 9800 GX2 doesn't appear to be an important factor, with the card consuming the same number of PCI slots as an 8800 GTX or 8800 Ultra which use much larger coolers.  Frankly, unless you take the card apart you wouldn't know its a dual PCB solution. It The LEDs only add to the superior packaging and great presentation. Our verdict?  As a single card, the 9800 GX2 offers reason for much optimism from the enthusiast community. While some would prefer a single monolithic GPU, the 9800 GX2 achieves a level of performance currently out of reach to the monolithic design; results perhaps especially important to those opting for non nForce platforms. Our biggest concern is the 512 Meg limitation of the GPU which, under some circumstances, may be a very real bottleneck.

Final Reflections

After some reflection upon all the hardware we have tested, it occurs to us that we really do have a lot of options right now. Nvidia has a solid spread of performance/price ratios and many ways of achieving those goals. We simply cannot remember a time in recent history when so many options have been available at so many price points. And this really hits home: there really is a little something for everybody right now, with excellent value in the plethora of solutions currently available. Even the sub $200 market is well covered with 9600 GT and 9600 GT SLI, which we were unfortunately unable to include in this round of tests.

Sneak Peak: And of course... a sneak peek at things to come..