 | |||
|
|
|
|
|
 |
NVIDIA GeForce 6800 GS Performance Preview November 07, 2005 |
|
 |
|
| |
Summary: With a 425MHz graphics core and 500MHz memory, NVIDIA's GeForce 6800 GS is well-equipped to take on the ATI RADEON X1600 XT. NVIDIA has even spiced up the package further by using the 7800 GT PCB and throwing on copper cooling, making this board ideal for even higher clock speeds. See how this new card performs in both single card and SLI configurations in today's latest titles inside. And of course, don't forget the overclocking!
 Introduction | Page:: ( 1 / 19 ) |
As you probably know by now, the GeForce 6800 features a 12-pixel pipeline architecture, with five vertex units backing up the pixel shaders. The feature that stands out the most though is the GeForce 6800’s 256-bit memory interface, with four 64-bit memory controllers responsible for keeping the graphics core fed with data.
This feature is what really allows the GeForce 6800 to stand out from its younger sibling, the GeForce 6600 GT. The GeForce 6600 GT sports much higher clocks than the GeForce 6800 (500MHz on the graphics core and memory versus 325MHz core/300MHz memory on the GeForce 6800 256MB) allowing it to compete very closely with the 6800 in performance as long as the visual effects are kept in check, but once eye candy features such as 4x anti-aliasing are turned on, the GeForce 6800 begins to pull away from the GeForce 6600 GT and many other cards in the mainstream segment. This is because the GeForce 6800’s 256-bit memory controller provides considerably more bandwidth than the 6600 GT’s narrower 128-bit memory interface – 22.4GB/sec for the 6800 128MB versus 16GB/sec on the GeForce 6600 GT.
With more memory bandwidth, the GeForce 6800 is better equipped to handle high screen resolution environments and/or memory-intensive operations such as 4x anti-aliasing. This is one of the chief reasons why it became such a popular upgrade solution at the sub-$300 price point.
But NVIDIA wasn’t the only one to integrate a 256-bit memory interface into a mainstream graphics card. Earlier this year, ATI launched their GeForce 6800 competitor, the RADEON X800.
[image]
| <% print_image("01"); %> | <% print_image("02"); %> | <% print_image("03"); %> |
The X800 boasts slightly higher clocks (400MHz on the graphics core versus 325MHz for the GeForce 6800) and performs very closely with the GeForce 6800, with the GeForce board performing better in OpenGL games like IL-2 and DOOM 3, while the X800 outran the GeForce board in D3D titles such as Half-Life 2 and Battlefield 2 (the GeForce 6800 currently runs slightly faster than the X800 in Far Cry, although this wasn’t the case at the beginning of the year). The real clincher for the X800 though was supposed to be its price, with 128MB boards carrying an MSRP of $199 while 256MB cards were priced at $250.
Neither X800 offering really got a chance to take off though due to late availability. By the time X800 boards really hit the market in large quantities, the GeForce 6800 was priced lower and offered the added benefits of SLI and shader model 3.0 support. ATI then tried to up the ante further with the X800 GTO sporting even higher clocks than the X800, but this card hit the market to late to make an impact and with its stealth introduction in September ATI relied too heavily on their board partners to get the message across.
Later this month, ATI plans to take a third stab at the GeForce 6800 with their RADEON X1600 XT. The X1600 XT ships with a 590MHz core clock speed with 12 pixel pipes and 256MB of memory running at a whopping 690MHz. On paper, these figures, along with the X1600 XT’s support for shader model 3.0, appear to challenge the GeForce 6800 like no other ATI offering before...Which is exactly why NVIDIA has decided to preemptively strike ATI first with a new GPU. The GeForce 6800 GS!
[image]
| <% print_image("04"); %> | <% print_image("05"); %> | <% print_image("06"); %> |
| Specifcations | Page:: ( 2 / 19 ) |
Building the GeForce 6800 GS
With manufacturing of the GeForce 7800 GT and GTX going along so well, the high-end card of yesteryear, NVIDIA’s GeForce 6800 Ultra, is no longer in production. In fact, NVIDIA’s board partners have told us that production of the GeForce 6800 and 6800 GT just recently came to an end as well (although production may be over, these cards can still be found in the sales channel, but once supplies dry up these boards will be gone forever). Instead, NVIDIA has turned to an entirely new process for the GeForce 6800 GS – TSMC’s tried and true 110-nanometer manufacturing process.
This is the same manufacturing process NVIDIA has used for a string of products. The GeForce 6200 and 6600 family are both built on TSMC’s 110-nm process, as well as the high-end GeForce 7800 GT and 7800 GTX. NVIDIA’s previous manufacturing partner for the GeForce 6800 family was IBM, whose 130-nm process was used on NV40 (GeForce 6800 Ultra/GT), NV45 (PCI Express variant of the GeForce 6800 Ultra/GT), as well as NV41 (PCI-E native version of GeForce 6800). With the introduction of the GeForce 6800 GS, NVIDIA’s essentially moved all their production back over to TSMC.
Like NV41, NVIDIA’s NV42 GeForce 6800 GS GPU is built entirely from the ground up with 12 pixel pipelines and 5 vertex units. (The GeForce 6800 Ultra and GT both feature 16 pixel pipes and six vertex units.) This means that like NV41, you won’t be able to unlock any additional pixel or vertex pipelines on GeForce 6800 GS – they simply aren’t there.
[image]
| <% print_image("07"); %> | <% print_image("08"); %> | <% print_image("09"); %> |
Thanks to the smaller manufacturing process, NVIDIA can cram the GeForce 6800 GS’ transistors into a smaller die area. This also helps to reduce manufacturing costs, as NVIDIA/TSMC yield more chips per silicon wafer. With fewer functional units inside, transistor count is reduced from 222 million in 6800 Ultra/GT to 202 million in GeForce 6800 GS (in comparison, the X1600 XT contains 157 million transistors while NV41 contained 190 million. According to NVIDIA the difference between transistor counts in NV41 versus the newer NV42 “is related to different libraries and manufacturing processes between IBM and TSMC”). Although the 6800 GS’ NV42 die is a little larger than X1600 XT (and thus costs a little bit more for NVIDIA to produce than the X1600 XT for ATI assuming equal yields), thanks to its smaller process, it’s still the least expensive to manufacture GeForce 6800 variant NVIDIA has produced to date. As a result, the GeForce 6800 GS carries an MSRP of $249, that’s $51 lower than the GeForce 6800 when it was introduced.
Besides lower production costs, another added benefit of TSMC’s 110-nm process is that it has proven to scale ridiculously well to high clock speeds. Even massive 300+ million transistor chips like the GeForce 7800 GTX have hit clocks of over 500MHz on retail graphics cards, while the less complex GeForce 6600 family has scaled well also.
The GeForce 6800 GS is no exception, as NVIDIA clocks the graphics core at 425MHz, that’s 100MHz higher than the GeForce 6800. Meanwhile the memory subsystem runs at 500MHz (1.0GHz effective), giving the GeForce 6800 GS the same 32GB/sec of peak memory bandwidth found on NVIDIA’s GeForce 6800 GT. This is an improvement of 200MHz over the 256MB GeForce 6800, which shipped with 300MHz memory (the memory on 128MB GeForce 6800 cards ran at 350MHz). Also like the GeForce 6800 GT, the GeForce 6800 GS ships with 256MB of GDDR3 memory.
This chart summarizes the key features found in NVIDIA’s GeForce 6800 GPUs:
| GeForce 6800 Series Comparison | ||||
| GeForce 6800 Ultra | GeForce 6800 GT | GeForce 6800 GS | GeForce 6800 | |
| Core Clock (MHz) | 400 | 350 | 425 | 325 |
| Memory Speed (MHz) | 550 | 500 | 500 | 300 (256MB) 350 (128MB) |
| Memory Interface Width | 256-bit | 256-bit | 256-bit | 256-bit |
| Memory Size & Type | 256MB GDDR3 | 256MB GDDR3 | 256MB GDDR3 | 256MB DDR1, 128MB DDR1 |
| Memory Bandwidth (GB/sec) | 35.2 | 32 | 32 | 19.2 (256MB) 22.4 (128MB) |
| Texel Fill-Rate (Gtexels/sec) | 6.4 | 5.6 | 5.1 | 3.9 |
| Vertices/sec (million) | 600 | 525 | 531.25 | 406 |
| Pixel Pipelines | 16 | 16 | 12 | 12 |
| Vertex Units | 6 | 6 | 5 | 5 |
| ||||
| Board analysis | Page:: ( 3 / 19 ) |
[image]
| <% print_image("10"); %> | <% print_image("11"); %> |
If you’re familiar with the board design of NVIDIA’s GeForce 6800 GPUs, you’ll quickly recognize quite a few differences between the GeForce 6800 GS and its direct predecessor, the GeForce 6800. In fact, the boards have practically nothing in common. But it doesn’t stop there, as the GeForce 6800 GS doesn’t even follow the GeForce 6800 GT’s board design.
Instead, the GeForce 6800 GS reference board supplied to us by NVIDIA is a 100% replica of the GeForce 7800 GT’s reference board design, right down to the component placement and the use of both polymer and electrolytic capacitors. The only difference lies in the cooler used on the two cards.
[image]
| <% print_image("12"); %> | <% print_image("13"); %> |
In laymen’s terms, what this basically means is that NVIDIA has basically taken the GeForce 6800 GS GPU and slapped it onto a GeForce 7800 GT PCB. We were absolutely floored when we first saw this! Of course, with dramatically higher clocks than its predecessor, the move to the new board design was a requirement for the GeForce 6800 GS, we just didn’t expect NVIDIA to be so aggressive on a mainstream board.
Overclockers are going to love this.
This PCB has been built from the ground up for high clocks. It is after all, not uncommon to find GeForce 7800 GTs running overclocked right around 490MHz-500MHz on stock cooling. As a result, this means that the GeForce 6800 GS is longer than both the GeForce 6800 and 6800 GT (although it’s not much in the case of the 6800 GT), making it a little less than ideal for some small form factor (SFF) boxes, but we have a feeling SFF users intrigued by the 6800 GS will find a way to make it work in their system. According to NVIDIA, the GeForce 6800 GS draws up to 70W of power, so a 350-watt PSU is recommended for single card setups, while a 420W PSU is recommended for SLI.
The cooling unit used on the GeForce 6800 GS is like nothing we’ve ever seen on an NVIDIA reference board. While at first glance it resembles the GeForce 6800 GT heatsink/fan unit, taking a closer look reveals that NVIDIA has employed a copper/aluminum combination for the GeForce 6800 GS’ cooling. This marks the first time NVIDIA has used copper on a reference board since the GeForce FX 5800 Ultra.
The GPU itself is cooled by a copper heatsink. When combined with the board’s fan, the copper heatsink does a very good job of keeping the graphics core cool. In all honesty, this is probably a bit of overkill for a 12-pipe 110-nm GPU, even if it is running at 425MHz. We noted core temperatures never topped 55 degrees Celsius, further reinforcing this. (Again, this is all the more reason why we’re so impressed with the GeForce 6800 GS’ board design.)
[image]
| <% print_image("14"); %> | <% print_image("15"); %> |
To help keep the memory cool, NVIDIA then employs a separate aluminum heatsink. This heatsink, as well as the aluminum heatpipe and blower-style fan, are all borrowed completely from the reference design cooler used on the GeForce 6800 GT.
It will be interesting to see how closely NVIDIA’s board partners follow the GeForce 6800 GS reference design. We don’t think anyone would make any changes to the basic board design and its use of the 7800 GT PCB, after all the move does have the added benefit of helping to simplify production (as multiple card lines will be based on one PCB), but we will be curious to see how many of NVIDIA’s board partners integrate the copper cooling on their retail GeForce 6800 GS cards. We wouldn’t be surprised to see more than one board partner take the easy way out and simply take the aluminum GeForce 6800 GT cooler and use it on their GeForce 6800 GS board.
| Test Systems | Page:: ( 4 / 19 ) |
System Setup
AMD Athlon 64 FX-57
ASUS A8N-SLI Deluxe
2GB OCZ DDR400 SDRAM
ATI RADEON X1600 XT
ATI RADEON X800 XL
CATALYST 5.10a hotfix driver
NVIDIA GeForce 7800 GTX
NVIDIA GeForce 7800 GT
NVIDIA GeForce 6800 GT
NVIDIA GeForce 6800 GS
NVIDIA GeForce 6800 256MB
Driver version ForceWare 81.87
250GB Maxtor Hard Drive Maxline III SATA Hard Drive w/16MB Cache
Windows XP Professional SP1
DirectX 9.0c
Benchmarks
IL-2 Sturmovik: Forgotten Battles
Far Cry
Half-Life 2
F.E.A.R.
Battlefield 2
Quake 4
| IL-2 4xAA/8xAF | Page:: ( 5 / 19 ) |
IL-2: FB – OpenGL
| Far Cry 4xAA/8xAF | Page:: ( 6 / 19 ) |
Far Cry – Direct3D
| Half-Life 2 | Page:: ( 7 / 19 ) |
Half-Life 2 – Direct3D
| Half-Life 2 4xAA/8xAF | Page:: ( 8 / 19 ) |
Half-Life 2 – Direct3D
| Battlefield 2 | Page:: ( 9 / 19 ) |
Battlefield 2 – Direct3D
| Quake 4 | Page:: ( 10 / 19 ) |
Quake 4 – OpenGL
| Quake 4 4xAA/8xAF | Page:: ( 11 / 19 ) |
Quake 4 – OpenGL
| F.E.A.R. Performance | Page:: ( 12 / 19 ) |
F.E.A.R. – Direct3D
| F.E.A.R. 4xAA/8xAF | Page:: ( 13 / 19 ) |
F.E.A.R. – Direct3D
| Overclocking | Page:: ( 14 / 19 ) |
F.E.A.R. 4xAA/8xAF
Quake 4 4xAA/8xAF
| SLI: Half-Life 2 | Page:: ( 15 / 19 ) |
F.E.A.R. – Direct3D
| SLI Gaming: Quake 4 | Page:: ( 16 / 19 ) |
Quake 4 – OpenGL
| SLI Gaming: FEAR | Page:: ( 17 / 19 ) |
F.E.A.R. – Direct3D
| SLI Gaming: IL-2 | Page:: ( 18 / 19 ) |
IL-2 – OpenGL
| Conclusion | Page:: ( 19 / 19 ) |
With the debut of the GeForce 6800 GS, NVIDIA has finally addressed this important segment of the graphics market, and they didn’t do it lightly.
With dramatically higher clocks, over 100MHz on the graphics core and memory, the GeForce 6800 GS delivers considerably more performance than its predecessor in today’s latest games. F.E.A.R. performance is up by a factor of 1.5x at 1280x1024 without AA/AF, making the game playable at resolutions that just weren’t possible before with the GeForce 6800, while Quake 4 frame rates improved by over 20 fps in a few cases.
In our testing, the GeForce 6800 GS’ completely outclassed its intended competitor, the RADEON X1600 XT, in performance. In most of our benchmarks, the GeForce 6800 GS outperformed the X1600 XT by a double-digit margin. Thanks to its 256-bit memory interface and 500MHz memory, the GeForce 6800 GS really excels in comparison to the X1600 XT at high resolutions with AA/AF. The X1600 XT’s memory is clocked faster, but since it only has a 128-bit memory interface, the 6800 GS boasts nearly 10GB/sec more of peak memory bandwidth than the X1600 XT.
For even more performance, you can double up on GeForce 6800 GS boards for SLI. This buys you performance that’s even greater than the GeForce 7800 GTX for $500.
When you factor in price (both cards retail for the same $249 MSRP), the GeForce 6800 GS becomes even more of a no-brainer. As we said in our last Quake 4 performance article, ATI desperately needs to release a third X1800 SKU that’s tailored for the mainstream segment. In addition, they’re going to have to slash prices on their RADEON X1600 XT, as it just isn’t competitive with other cards in its price range.
With the debut of the GeForce 6800 GS, expect the GeForce 6800 and 6800 GT to slowly disappear. According to NVIDIA, the GeForce 6800 GS is “another hard launch” meaning that 6800 GS boards from third-party board vendors should be hitting retail shelves right about now. However, a quick scan of both Newegg and ZipZoomfly reveals that no 6800 GS cards have hit the market just yet, and only four board manufacturers have announced cards: XFX and PNY (both of which offer an overclocked GeForce 6800 GS SKU) and Leadtek and EVGA (who stick with the stock speeds). If recent history is any indication, when it does hit retail, prices could fall pretty quickly. This could make the GeForce 6800 GS a very popular upgrade this upcoming holiday season.
In our opinion, it’s the card to get at the $250 price point. ATI’s RADEON X800 XL delivers competitive performance thanks to its 16-pixel pipeline architecture, but with the lack of shader model 3.0 support, its shelf-life could be short-lived. With ATI introducing top-to-bottom SM3.0 hardware just recently game developers may have little incentive to include a custom 2.0b path for X700/X800-series hardware. Therefore, if you’re going to spend the money, you’d be better off with SM3.0 hardware.