The specifications of the GeForce 6800
GS are closer to the GeForce 6800 GT. The GeForce 6800 GS has fewer
pixel pipelines and vertex processors than the GeForce 6800 GT,
but it matches and exceeds the GeForce 6800 GT in memory bandwidth
and geometry processing, which can be partially attributed to the
increased core clock speed (425MHz vs. 350MHz).
Special note should be made of the core and memory clock speeds
of the XFX GeForce 6800 GS XXX Edition - a 12% increase (425MHz
vs. 485MHz) in the core speed and a 10% increase (1000MHz vs. 1100MHz)
in the memory speed. XFX is certainly giving serious consideration
to the gamer!
The chart below outlines the specifications of the GeForce 6800
Series, including XFX's two new offerings.
GeForce 6800 Series
The maximum power draw of a single GeForce 6800 GS is 75W. A
350W power supply is recommended for systems with a single card
and at least a 420W power supply for systems with an SLI configuration.
The following items summarize the key
features of the GeForce 6800 GS.
Microsoft DirectX 9.0c Shader
Model 3.0 Support
High-Speed GDDR3 Memory Interface
256-Bit Memory Interface with
Advanced Memory Control
64-Bit Floating Point Texture
Filtering and Blending
NVIDIA ForceWare Graphics Driver
WHQL Version 81.95
NVIDIA nForce4 AMD Driver Package
Vsync Disabled / 99Hz @ 1600x1200
Refresh Rate / 84Hz at 1920x1440 / 79Hz at 2048x1536
Windows XP Professional with Service
Pack 2 / DirectX 9.0c
AquaMark3 - v1.0
3DMark03 Pro - v3.6.0
3DMark2005 Pro - v1.2.0
F.E.A.R. - v1.02
Battlefield 2 - v1.12
Chronicles of Riddick, EFBB -
Far Cry - v1.31
Doom 3 - v1.0
used to collect frame rate data in some benchmarks.
The driver image setting was set
to high quality (trilinear optimization
OFF, anisotropic mip filter optimization
OFF, anisotropic sample optimization
I overclocked the XFX GeForce 6800
GS XXX Edition to 534MHz on the core and 1.20GHz on the memory without
any signs of heat buildup or stability problems. However, since
I was going to check out SLI compatibility with a NVIDIA reference
sample, I decided to limit the overclock to what the reference design
card could achieve and maintain. So, taking a deep breath I started
to test the overclock potential of the reference card.
I began the familiar ordeal of increasing clock speeds and testing
for stability. I was impressed as the card reached 510MHz on the
core and 1.12GHz on the memory without any indication of overheating
or instability. The potential was there to run the reference card
at the default clock speeds of the XFX GeForce 6800 GS XXX Edition
in an SLI configuration.
The next step was to find out if the
cards were compatible in SLI and could run together at 485MHz/1.10GHz.
After installing the cards and ensuring all power connections were
tight I turned on the power and booted the system. Everything went
smoothly with the system recognizing both cards in device manager.
Entering the ForceWare driver control panel I made the required
adjustments for SLI operation and rebooted.
XFX vs. Reference GeForce
Upong rebooting, I entering the driver control panel and selected
the "Clock Frequency Settings" applet to check the default settings.
I was a little dismayed as the settings were those of the reference
card (425MHz/1.00GHz). Not to be deterred, I set overclocking to
manual and ran the "Optimal Clock Frequencies" test, which returned
a setting of 466MHz/1.08GHz. I tested the setting in both Aquamark3
and 3DMark05. Both benchmarks ran flawlessly and without a whimper
from the cards so I decided to undertake some serious gaming with
XFX vs. Reference GeForce
Almost immediately I noticed some odd artifacts and found that
the problem was coming from a program I had running in the background.
I had not taken the time to do a fresh install of Windows XP before
starting this review and the drive I was using was over 50% of capacity
with various programs, photos, and videos. After closing the program
I went for about an hour of gaming. Not experiencing any problems,
I decided to try the cards out in Far Cry. The cards went through
three maps with no problems.
Mixed GeForce 6800 GS in SLI Configuration
The stiffening bar
is evident in this photo.
Two XFX GeForce 6800 GS XXX Edition cards would look much nicer.
Now back to the control panel to increase the clocks a bit more.
To get to the point, I stopped at 510MHz/1.12GHz, which was the
same overclock I had achieved with the reference card. I backed
off the overclock and set the clocks for this review at 485MHz/1.10GHz,
which is the same as the default settings of the XFX 6800 GS XXX
Edition. It should be noted that there appeared to be more headroom
for clocking higher, but with stock cooling I decided to stop and
not press my luck any further.
Note that the overclock results I achieved may or may not be
valid for another XFX GeForce 6800 GS XXX Edition as there are variances
in the clock capabilities of both core and memory chips. This bares
repeating XFX's claim - "During selection of the components, the
absolute top is being separated from the masses, including the GPU's.
During the production, only the best yield [top 10%] is selected
to go forward into the XXX production."
(Note: The best solution here is to just buy two XFX GeForce
6800 GS XXX Edition cards to have an overclocked setup running at
485MHz/1.10GHz. But for the sake of determining how compatible two
GeForce 6800 GS cards from different sources are, the mismatched
pair was used. So, this review is "tweaked" for those of you that
may already have one GeForce 6800 GS graphics card and are contemplating
the purchase of another card to run in SLI.)
...and with that out of the way, on to the benchmarks!