![[H]ardOCP](/images/blank.gif){kind=small}
- Date:
- Sunday , October 28, 2007
- Author:
- Brent Justice
- Editor:
- Kyle Bennett
- Google +1
NVIDIA GeForce 8800 GT
The new GeForce 8800 GT gives the GeForce 8800 GTS and 2900 XT a run for the money. We put them to the test, along with the 8800 GTX and Ultra, using the Crysis and UT3 Demos. Did we mention MSRP is $200 to $249?
Introduction
NVIDIA still has no competition at the high end when it comes to the 8800 GTX and Ultra. The GTX and Ultra offer the fastest single GPU video card gaming solutions on the planet. At the GeForce 8800 GTS level though, there is plenty of competition with the AMD/ATI Radeon HD 2900 XT. While this video card started out quite rough for AMD, we are finding now with the latest drivers that it is doing quite well in games we have tested. We will forego all discussion about power and focus on performance. We have analyzed performance in several DX10 games now including Lost Planet, Call of Juarez, BioShock, World in Conflict, and the DX9 games Half Life 2: Episode 2 and Team Fortress 2/Portal and even Enemy Territory Quake Wars. We are consistently finding that the Radeon HD 2900 XT competes well with the 8800 GTS, sometimes offering a better gameplay experience. Of course, what you guys really want to know is how they all perform in Crysis and Unreal Tournament 3, and in this evaluation we will find out.
GeForce 8800 GT
The GeForce 8800 GT will be priced between $199 and $249 according to NVIDIA. You will also probably find some above $250 starting out, but prices should fall over time. The video card we are evaluating today is the reference non-overclocked version. The price is one of the most important “features” of this video card because it is priced well below the Radeon HD 2900 XT and GeForce 8800 GTS 320/640 MB video cards. At $200 it is $150 less than the cheapest 640 MB GeForce 8800 GTS. The key question to ask is will it be faster or slower than the 8800 GTS and this is exactly what we will answer.
The specifications are listed above; one of the first things you will notice is that the 8800 GT actually has more transistors than the 8800 GTS and GTX. This is because it adds some new features such as PCI-Express 2.0 (PCIe Gen 2) support, as well as supporting NVIDIA’s PureVideo HD 2nd gen video processor found in the GeForce 8600 GTS. NVIDIA has also moved some of the display I/O functionally off the PCB and onto the die itself add up to a higher transistor count.
This GPU is based on the new 65nm manufacturing process instead of the G80’s 90nm process. This helps reduce power and heat required, and as a result the maximum TDP of this video card is 110 Watts, compare that to 185 Watts on the 8800 GTX and 145 Watts on the 8800 GTS. With the reduction in TDP NVIDIA was able to make this video card a single-slot solution that is the same length as a 8800 GTS.
Architecture
There are 112 stream processors present, which is more than the GeForce 8800 GTS and less than the GeForce 8800 GTX. The stream processors are clocked at 1.5 GHz though, which is faster than even the 8800 GTX, in fact, they are the same speed as the 8800 Ultra. The ROPs are cut down to 16 from the 8800 GTX’s 24 and the 8800 GTS’s 20. The GT’s texture units however have received a bump compared to the GTS.
In the G80 design there are 8 blocks that contain 16 stream processors and 8 texturing units per block. On the GeForce 8800 GTX all 8 blocks are in play and we have 32 texturing units and 64 texturing processors available. For the GeForce 8800 GTS two blocks are removed to give 6 blocks total providing 96 stream processors and 24 texture units with 48 texture filtering processors. However, on the new GeForce 8800 GT only one block is removed, for a total of 7 blocks (1 more than the GTS and 1 less than the GTX) and they have moved to a 1:1 ratio for Texture Address/Filtering. This means we have 112 stream processors, 56 texture address units and 56 texture units.
This all means the 8800 GT has more shader and texture horsepower than the GeForce 8800 GTS. All of these units run at a core speed of 600 MHz versus 500 MHz on the 8800 GTS and 575 MHz on the 8800 GTX. For reference the core speed on the GeForce 8800 Ultra is 612 MHz, so these units are clocked almost as fast as an Ultra, though there are less of them.
Memory
The only part of the GPU configuration that may seem bottlenecked is the use of a 256-bit memory bus. The GeForce 8800 GTS uses a 320-bit wide bus and the GTX has a 384-bit wide bus. However, NVIDIA has offset this narrow bus by clocking the memory modules at a very high 900MHz (1.8 GHz)! This provides a memory bandwidth of 57 GB/sec which is only 7 GB/sec less than the GeForce 8800 GTS. NVIDIA has also changed the amount to a standard 512 MB of GDDR3 for this video card. You may also find some manufacturers offering 256 MB models, hence the low $200 price point mentioned.
New Transparency Multisampling Algorithm
NVIDIA also now has a new transparency multisampling algorithm in use that it has implanted in its latest drivers. This new algorithm works on every GeForce 8 series video cards and is not restricted to just the GeForce 8800 GT. This new mode is employed by the latest drivers, version 167.37 and the new 169.01. NVIDIA has developed a new transparency multisampling method that has image quality almost similar to transparent supersampling but without the large performance hit. This new mode replaces the previous TRMS with a new TRMS; the option in the driver control panel is still labeled the same however. NVIDIA claims that the new TRMS mode is on average 6% slower than standard 4X AA. This feature will certainly be welcomed as we can enable TRMS and receive better antialiasing on alpha textures compared to the previous algorithm, with less of a performance hit than TRSS takes.
In the Flesh
The GeForce 8800 GT is a single-slot video card utilizing a heatpipe heatsink underneath the shroud which covers the entire video card this time. The heatsink makes physical contact with the memory modules and power circuitry, and with the fan creates an active cooling system for the entire video card. The shroud itself even aids in heatsink duty since it is metal and in contact with the heatsink itself, so heat will transfer throughout the entire shroud, and it does get very hot at full load.
The fan itself is small compared to the GeForce 8800 GTS’s fan, and when we booted up these video cards we noticed at POST that the fan ramps up to full speed and it is annoyingly loud. Thankfully it spins down in Windows and we did not once notice it spin up to full speed in our gaming; even during the longest periods of gaming. In the second row of pictures, you can see where the heat is exhausted from the card along the top edge by the SLI connectors. That means the hot air will be directly aimed at your side panel in your case. The best case scenario would be to have a rear or side panel exhaust fan, or a side panel intake and rear exhaust.
Power and PCIe 2.0
Due to the lower power 65nm GPU this video card only requires one auxiliary power connector that is located at the rear of the card. NVIDIA recommends a minimum 400 W power supply with 26 amps for a single GPU configuration. This video card also fully supports PCI-Express 2.0 for forward looking systems. Thankfully it is backwards compatible with the current PCI-Express version and you should have no troubles running it on current motherboards. We are using an EVGA 680i motherboard and have had no troubles in single or SLI operation with it.
Video
The GeForce 8800 GT also supports dual-link HDCP and the latest PureVideo HD 2nd generation video processor like that found in the 8600 series. Remember the GeForce 8800 GTS, GTX, and, Ultra are missing this feature.
GTS Comparison
Physically the GeForce 8800 GT is the exact same length and width as the GeForce 8800 GTS which is 9” long. The heatsink shroud that covers the entire length of the video card makes it appear longer, but it is not. The main physical difference between the 8800 GTS and the 8800 GT is that the GT has a the single slot cooler.
Today’s Testing
Today we are going to concentrate on two very important games, two games that all gamers are most curious about playing this year, Crysis and Unreal Tournament 3. Both games have recently released new demos that show off some gameplay. In the case of Crysis the entire first level is available to play in the demo. We will be testing the GeForce 8800 GT, the 320MB and 640MB GeForce 8800 GTS cards, the GeForce 8800 GTX, GeForce 8800 Ultra, and two 8800 GT cards in SLI.
We will evaluate both demos and find the highest playable settings with all video cards with screenshots to follow. While we have done a rather in-depth performance testing with all of these video cards today it won’t be until both full version games are released until we will really dive deep into looking at image quality in extreme detail.