Rage3D NVIDIA GeForce 7950 GT Review
By Mark "Ratchet" Thorne - ratchet@rage3d.com
September 14th, 2006
[ Print ] - [ Close ]
Introduction

NVIDIA 7950 GT
NVIDIA 7950 GT
So here we have it, my launch day review of the 7950 GT… ok, it’s not technically launch day since the embargo on 7950 GT information was lifted a little over a week ago, but the embargo on benchmarks and analysis lifts today and let’s face it, that’s what everyone tunes in for (are you even reading this?).

The 7950 GT, for those of you wondering, is the successor to NVIDIA’s now discontinued 7900 GT. It, like the 7900, features 24 fragment shaders, 8 vertex shaders, and 16 ROPs (render output units). Unlike the 7900 GT, the 7950 GT has 512MB memory and… well, that’s about it… it’s a 512MB 7900 GT with higher core and memory clocks. Should your attention span be on par with mine you probably need a visualization aid, so here’s a nice chart I made just for you:

NVIDIA's Lineup
Enthusiast 7950 GX2 $549
7900 GTX $449
Performance 7950 GT $299
Mainstream 7900 GS $199
7600 GT $169
Value 7600 GS $129
7300 $99

You can see that the line has blurred significantly between NVIDIA’s enthusiast and performance products. Now, with 512MB memory onboard, the only thing separating the 7950 GT and the enthusiast level 7900 GTX above it is clock speeds and price. Price, being the key factor in any product purchasing decision (for most of use plebs, anyhow), is what defines a graphics cards market segment. So, at $299, the 7950 GT goes toe-to-toe with ATI’s recently announced $279 X1900 XT 256MB. NVIDIA would like for it to go up against ATI’s X1900 GT, but that’s just not the reality of the market right now. We’ll still throw an X1900 GT in the mix as a comparison point, but the real decision should you find yourself with around $300 in your pocket is between NVIDIA's 7950 GT and ATI's X1900 XT 256MB.

Let’s get started.

Test Setup

Resolutions

Image Quality Settings

Games Benchmarks (click for settings)

Test Systems NVIDIA ATI
Motherboard
( chipset )		 Foxconn C51XEM2AA
(NForce 590 SLI) 		MSI K9A Platinum
(ATI RD580/SB600)
CPU AMD Athlon FX-62 @ 2.8GHz
Graphics Card

NVIDIA 7950 GT
BFG 7900 GTX OC

ATI Radeon X1900 XT 256MB
HIS Radeon X1900 GT
Driver Version Forceware 91.47 Beta Catalyst 6.8 WHQL
Memory
( Timings )		 2GB (2x1024MB) SuperTalent PC2-6400 DDR2 @ 800MHZ
( 4-4-3-8 2T)
Hard Disk Western Digital Caviar WD2500KS SE16 250GB
Sound Onboard
Network Onboard
PSU PC Power & Cooling 1KW Turbo-Cool Quad-SLI
OS Windows XP Pro SP2

Card Specifications NVIDIA 7950 GT ATI X1900 XT 256MB HIS X1900 GT BFG 7900 GTX OC
Core G71 R580 R580 G71
Silicon Process 90nm 90nm 90nm 90nm
Transistor Count
(millions)		 278 384 384 278
Core Speed MHz 550 625 575 670
Memory Speed MHz (Effective) 700
(1.4GHz)		 725
(1.55GHz)		 600
(1.2GHz)		 820
(1.64GHz)
Memory Size 512 MB 256 MB 256 MB 512 MB
Bus Standard PEG 16x PEG x16 PEG x16 PEG 16x
Bus Width 256bit 256bit 256bit 256bit
ROPs 16 16 12 16
Pixel Shaders 24 48 36 24
Vertex Shaders 8 8 8 8
Peak Memory Bandwidth
(GB/s)		 44.8 46.4 38.4 51.2
Pixel Fillrate
(million pixels/sec)		 8,800 10,000 6,900 10,720
Texel Fillrate
(million texels/sec)		 13,200 10,000 6,900 16,080
API Compliancy DX 9.0c DX 9.0c DX 9.0c DX 9.0c

The Windows XP desktop was set to 1280x960 with a 32bit color depth and 85Hz refresh rate for all tests. Refresh rate locks for 3D graphics modes, as supported by both NVIDIA and ATI graphics control panels, was not enabled. V-Sync was forced off via the graphics card control panel as well. For the NVIDIA cards "High Image Quality" was enabled. All other graphics card control panel settings for the ATI cards were left to their default settings.

Anti-Aliasing and Anisotropy were applied in the game engine where the options existed. For games that did not support those options natively, the graphics card control panel was used.

Custom batch files were used when possible for automated benchmarking, which are available upon request. When manual benchmarking was necessary Fraps was used.

Benchmarking was done with Windows set to the "Adjust for best performance" profile and all unnecessary Windows services and hardware devices were disabled. The latest drivers for each necessary hardware component were installed prior to testing and kept consistent throughout.

Sound and networking interfaces were enabled for all tests.

Windows XP was installed fresh on two seperate but identical hard-drives prior to testing (one for the ATI system, one for the NVIDIA system).

The Card

The 7950 GT is a relatively svelte card with not much in the way of surface clutter. The cooler is also pretty small, and the fan is quiet even under load. Beneath the cooler is NVIDIA’s G71 GPU.

7950 GT Layout
7950 GT Layout
G71 GPU Core
G71 GPU Core
7950 GT Fan
7950 GT Fan
7950 GT Heatsink/Fan
7950 GT Heatsink/Fan
7950 GT Heatsink/Fan
7950 GT Heatsink/Fan
7950 GT Heatsink/Fan
7950 GT Heatsink/Fan

The card has 512MB of GDDR3 memory, all of it on one side arrayed around the GPU in pairs of two. They are Infineon model HYB18H512321AF-14 rated for 1.4ns or 700MHz (1.4GHz).

Memory Layout
Memory Layout
Infineon 1.4ns GDDR3
Infineon 1.4ns GDDR3

On the front end there are two dual-link DVI interfaces so you can drive one or even two of those giant 30” LCDs without problem, and next to those is a Video In/Out port for you gamers that dabble in the multimedia stuff from time to time. HDCP is supported on all 7950 GTs.

Dual Dual-Link DVI
Dual Dual-Link DVI
PEG Power Connector
PEG Power Connector

You’ll notice that even though the card is smallish and doesn’t get very hot, it still requires extra power from the PSU to operate correctly.

Benchmarks (I)

Prey



Half-Life 2: Episode One



F.E.A.R.



Battlefield 2

Benchmarks (II)

Quake 4



Half-Life 2: Lost Coast



Splinter Cell: Chaos Theory



Far Cry

Overclocking

We managed to get some pretty decent overclocks on the 7950 GT which resulted in some respectable performance improvements. We managed to get the core up to 661MHz and the memory up to 818MHz without artifacts, but settled on 651MHz and 808MHz, respectively, due to some stability issues at the higher speeds. That’s 100Mhz over the stock core speed and 108MHz over the stock memory speed. Not bad at all.

Overclocking tests were done using NVIDIA’s Coolbits overclocking app, performance was tested with Splinter Cell Chaos Theory (it scales nicely), and stability and artifacts were checked in 3DMark06. Here are the performance results:

[ No AA / No AF ] [ 4x AA / 16x AF ]
Splinter Cell Chaos Theory
No Anti-Aliasing / No Anisotropy
 7950 GT 
93.7
69.6
60.4
49.0
 7950 GT @ 651c/808m 
110.1
82.3
71.6
58.2
 
0
60
120
Average Framerate
 1280x1024  1600x1200  1920x1200  2048x1536
Conclusion

I mentioned near the end of my X1950 article last week that the X1900 XT 256MB was a hell of a card for $279, but issued a caveat that NVIDIA’s 7950 GT was coming very soon and would make things very interesting. Today we have the 7950 GT, and it does indeed make things extremely interesting, but not in the way I fully expected.

To be honest I expected the 7950 GT to be faster than the X1900 XT 256MB, what with double the memory and a fully spec’ed G71 GPU powering it, but that’s not the case at all. If you’re NVIDIA then at best it’s a toss-up, but for all intents and purposes the X1900 XT 256MB is the winner here today, especially when AA and AF are applied. Even with half the memory the X1900 managed faster average framerates in every benchmark where AA was applied; quite contrary to what was expected.

That’s not to say the 7950 GT is a slow card, far from it. If you look at the results it’s not all that far off NVIDIA’s own $449 7900 GTX. For a card that costs $150 less, that doesn’t require an enormous cooler, and that is compact enough to fit in all but the smallest cases, that’s definitely something to be proud of. It’s just that when compared to the X1900 XT 256MB, it doesn’t shine as brightly as it would have if it were released a month ago.

NVIDIA would obviously have liked to have the 7950 GT reviewed against the X1900 GT, and looking at the performance results the reason for that is clear, but it must have taken them back a little when they saw the X1900 XT 256MB coming in at such an attractive price. Undoubtedly unprepared, the only recourse for NVIDIA now is to reduce the 7950 GT asking price in order to compete. Either that or hope that the immense mindshare they’ve built up over the last couple years can pull the 7950 GT through.

Like I said last week, competition kicks ass.