Official XS 7950GX2 Guide - Your Questions Answered

**Turok** · 08-20-2006, 12:33 PM

***Official XS 7950GX2 Guide***

Introduction:
The purpose of this guide is to answer all the questions about the new 7950GX2 that have been showing up in XS.
If you're planning on updateing to a single 7950GX2 or Quad-SLI, or you currently own one, this thread is for you.

Pros & Cons of a 7950gx2:
Pros
1) A single 7950gx2 is faster and its clocked lower than each 7900GT
2) Some 7900GT still have defective capacitors AFAIK, which causes the card to die in a short time.
3) A single 7950gx2 can run in about any board with a PCI-E slot (but check for compatibility just to be safe)
4) The vGPU is between that of 7900GT and GTX, but the vMem is lower than both the 7900GT and GTX
5) 7950gx2 is more like an underclocked 7900GTX than a pair of 7900GT.
6) Considering #4 & 5, the 7950gx2 has a good chance of easily reaching 2x 7900GTX SLI speeds with the proper cooling.
7) You can run Quad-SLI and crank up AA to 32x
8) A single 7950GX2 uses less power than a single x1900xt, and Quad-SLI 7950GX2 uses less power than a x1900xt CF setup.

Cons
1) The space between the cards is verry narrow, which makes it hard to put a better cooling solution.
2) The card was built to use low voltage, so you will need to volt mod it for Xtreme OCing.
3) Quad-SLI drivers are a bit immature atm
4) Quad-SLI makes a huge CPU bottleneck
5) I noticed some IQ defects on my Source engine games that were also visible in a few ATi vs nVidia IQ comparisons when the 7 series was first released, but Leviathan18 says he didnt see it with his 7800GT and 2x6600 GT. Im guessing its probably a temporary issue with the nVidia drivers, because the early 6 and 7 series cards had it but the problem was fixed

A few answers to some questions:
- The 7950GX2 runs about the same as 2x 7900GT on SLI on power consumption
- The inner card runs about 10 degrees C hotter than the outer card
- The SLI controller is on the inner card, and it can run fine with a passive chipset cooler
- All the data exchanged from the PCI-E slot goes through the card's SLI controller first
- You dont need 16x SLI to run Quad-SLI, but it will probably give you a bit of a performance gain

Recommended setup for Quad-SLI:
Even if you have Quad-SLI and good drivers, it doesnt mean you have the fastest GPU solution to date.
If you dont stress your cards enough, the performace will be even worse than 2x 7900GT.
Make sure your're running at GPU dependent settings above 1600x1200 with high filtering and max settings on current games.
However, In the future when Unreal Engine 3 and Crysis based games release you wont need to

Stressing your GPU isnt enough to avoid CPU Bottlenecking, tho.
You also need the hardware to process all that load at high resolutions:
Minimal specs for Quad-SLI:
- CPU: AM2 2.8Ghz or Conroe from 2.1Ghz to 3Ghz
- Mobo: nForce 590 or Intel 975x (w/ SLI hack) based mobo
- Mem: 2x 512mb DDR2 633Mhz CL 3
- PSU: OCZ GameXstream 600w, PCP&C Silencer 610 EPS12V, or simmilar

Recommended specs for Quad-SLI:
- CPU: AM2 >3.4Ghz or Conroe >3Ghz
- Mobo: Best nForce 590 or Intel 975x (w/ SLI hack) based mobo
- Mem: 2x 1Gb DDR2 1000Mhz CL 5
- PSU: PCP&C Silencer 750 EPS12V, PCP&C Turbo-Cool 850 SSI, or simmilar

Recommended Brands:
This question gets asked a lot of times, especially by people who never used a nVidia card before.
The best companies atm for a 7950GX2 are:
- eVGA
- XFX
- BFG

MSI is also good, but the 3 mentioned above have a
good reputation in overclocking and product quality

Cheap places to buy:
USA:
ZipZoomFly
eVGA 7950GX2 600/1200Mhz + HL2 + Free Shipping = $539.99

NewEgg -->All 7950GX2
eVGA 7950GX2 500/1200Mhz + Hitman = $526.12
MSI 7950GX2 500/1200Mhz + $30 MIR = $507.12

UK:
?

EU:
?

Drivers & Mobo Support:

Current ForceWare Drivers:
ForceWare 91.31 -> Current official release
ForceWare 91.33 Beta -> Try 91.33 if 91.31 and 91.45 isnt working properly
ForceWare 91.45 Beta -> best for Quad-SLI. Lets you make custom Quad-SLI profiles

nVidia's list of 7950gx2 mobo compatibility:
http://www.nvidia.com/content/geforce_gx2_sbios/us.asp

Quad-SLI on ANY chipset:
To run SLI on any chipset, you need this hacked ForceWare driver:
http://www.xtremesystems.org/forums/...d.php?t=106212
It lets you run SLI even on Intel and ATi based chipsets

Watercooling your 7950gx2:
People who are planning on running OCed Quad-SLI may need to update to waterblocks. Current watercooling solutions for the 7950GX2 dont perform as well, and are a bit expensive.
in this thread we discuss a bit about custom 7950GX2 blocks:
http://www.xtremesystems.org/forums/...d.php?t=104693
Unfortunately the thread eventually died and got pushed back in the Water Cooling section

But the thread is still useful if you want some inspiration on block building.
You could also try reviving the thread to see if someone can build you a block, or you could try build your own if you have a CNC machine and you can post there so everyone can see it

For anyone who is interrested, I made some detailed sketches of my 7950GX2:
I posted these measurements on the thread above, and you can use them as reference for block building.
The sketch shows a precise layout of all the chip locations, and each measurement is shown in both mm/cm and inches.
If you have any questions about the drawing, feel free to ask

Makeing your 7950GX2 wider:

The exact spaceing on a 7950GX2 from board to board is 1.6cm.
With double the spaceing you can easily fit the top 3 GPU blocks:
The DD Maze 4, the AX MP-1 and the Swiftech MCW60

This is the best solution so far:

Swiftech's GX2 Spacer kit for $19.95
It doubles the space between the cards.
the kit includes the following:
# 3 Male-Female 4-40 standoffs
# 1 Female-female pass-thru standoff
# 1 Female-Female 4-40 standoff
# 1 4-40 philips screw
# 1 MC14 Ramsink (for the SLI switch chip)
# 1 extended PCB.

Ramsink is sold separately.

Link:
http://www.swiftnets.com/products/7950GX2Spacerkit.asp

Volt Modding your 7950gx2:
Shamino made a nice volt mod guide at VR-Zone:

Try it at your own risk

http://www.vr-zone.com/?i=3659

BIOS Mod for your 7950gx2:
-=Merlin=- has a thread in the "Xtreme mods > Xtreme Graphx Vmods" section called "7950GX2 Bios Mod" where he's modding several 7950GX2 BIOS to run the fans at full load.
This is useful for benchmarking for those with stock cooler.
http://www.xtremesystems.org/forums/...d.php?t=113377

Stuff that could be added if this sticky becomes more popular:
* OCing results from other threads in XS:
* Reviews and Benchmarks from other sites:
* Info about 7900GX2:
- The first Quad-SLI card that measures like 30cm long

In the future the thread title could be changed to a thread dedicated to Quad-GPU solutions, since there are rumors that nVidia's top G80 card will be a Dual-GPU single card solution like the 7900GX2 and 7950GX2

At the moment I also have to update my LCD Guide which is pretty out dated.
If people can help me with info, reviews, terms, and new upcomming tech, then I could link the LCD Guide to this thread too for people who are interrested in HD gaming with their new Quad-SLI setup and a LCD greater than 1600x1200 resolutions. Even if the buyer is considering a CRT, the guide has some useful info that's true on all monitors.
http://www.xtremesystems.org/forums/...ad.php?t=71226

**GoriLLakoS** · 08-20-2006, 04:33 PM

We are you sayin that the best brands are

The best companies atm for a 7950GX2 are:
- eVGA
- XFX
- BFG

When all the companies use the nVidia reference pcb... ?

I think it's luck to find a better clocking card than others..

Did you forget the problems with the XFX clocked 7900s'?

**Turok** · 08-20-2006, 04:40 PM

Originally Posted by GoriLLakoS

We are you sayin that the best brands are

The best companies atm for a 7950GX2 are:
- eVGA
- XFX
- BFG

When all the companies use the nVidia reference pcb... ?

I think it's luck to find a better clocking card than others..

Did you forget the problems with the XFX clocked 7900s'?

My XFX 7950GX2 520/1300Mhz is my first nVidia card

Nope, I wasnt aware of that XFX problem. I was just told those were the top companies, but the main provider is eVGA and the rest are 3rd party. (Like Sapphire is with ATi)
I was assuming that it depended on the companie's parts and construction quality,
but if they are all the same, then Ill remove that section

**GoriLLakoS** · 08-20-2006, 04:45 PM

I think they are all the same...but let's hear others opinion too about the cards..

**[XC] leviathan18** · 08-20-2006, 04:46 PM

if they use reference board yes they are the same and is luck, but when they use their own models XGX BFG and EVGA are top... yes XFX had some issues with the 7900gt like most companies.

**Celcius** · 08-20-2006, 06:03 PM

Awesome thread, there's a lot of useful info here.
Perhaps this should be a stickie?

**perkam** · 08-20-2006, 09:09 PM

Originally Posted by Celcius

Awesome thread, there's a lot of useful info here.
Perhaps this should be a stickie?

Yes it seems the thread is getting a little sticky

Perkam

**BlackX** · 08-21-2006, 01:59 AM

Nice work Turok

**Hicks** · 08-21-2006, 07:19 AM

Nice info.

My 7950 is pissing me off, and im just about to send the POS back. God dam Nvidia drivers really do suck ass.

In Doom 3 it runs at 10fps at 1600x1200 with 16xaf. Pathetic. This is exact;y what happened with my 7800GTX.

Ive tryed 91.33, 91.37 and 91.45. All have slighty different settings, so hard to work out. Also video clips are dark, and i have to manually adust every time i play 1.

Aweful card, iam gutted i actually thought it was worth buying. I hope the X1950 is out soon, or ATI make a dual X1900 like this.

**Nistomax** · 08-21-2006, 12:18 PM

Very nice guide Turok.
I use a BFG tech 7950 and it runs like a dream. I only use 1280x1024 but i plan on getting a 24" Acer monitor soon. I'll try to review it for the guide, but my knowlege of computers is limited compared to the gurus of XS. I'll post in the guide if/when I get it.

My suggestions for the guide:
Make it more obvious that the 7950 is only supported on some motherboards. I get the impression that nvidia isnt going to help you if your card isnt on the list...

**Turok** · 08-21-2006, 02:01 PM

Originally Posted by Hicks

Nice info.

My 7950 is pissing me off, and im just about to send the POS back. God dam Nvidia drivers really do suck ass.

In Doom 3 it runs at 10fps at 1600x1200 with 16xaf. Pathetic. This is exact;y what happened with my 7800GTX.

Ive tryed 91.33, 91.37 and 91.45. All have slighty different settings, so hard to work out. Also video clips are dark, and i have to manually adust every time i play 1.

Aweful card, iam gutted i actually thought it was worth buying. I hope the X1950 is out soon, or ATI make a dual X1900 like this.

I had the same problem with the Prey Demo when I first got my card.
I was getting 10-15fps at 1600x1200 4xTSAA 16xAF
I tryed switching from the official FW 91.31 to the FW 91.33 beta and I got the problem fixed.
At the same settings I was always above 60fps

(like the benchmarks said)
Right now Im running on FW 91.45 and it still runs good, but dont know if performance got better compared to FW 91.33.

You also have to make sure your video settings are setup correctly, especially with the new ForceWare Control Panel

Some settings are a bit confusing, like the "Hardware acceleration" setting.
Mine is at "Single display performance mod"

The 7950GX2 is not a bad card. Its probably the only nVidia card worth buying IMO, because some GTs and even GTXs (AFAIK) still come with defective capacitors and die afther a short period of use.
Another reason is because ATi's single cards are superior, IMO
x1800xt > 7900GT
x1900xt & xtx > 79000GTX
and now x1950xtx is releasing soon with GDDR4

The only nVidia card atm that can counter ATi is the 7950GX2.
I got it simply because its better than 2x 7900GT, It can reach 2x 7900GTX speeds, and it only costs $500 - $550.
Just need a longer PCB bridge and Im happy

IMO, keep the 7950GX2. It consumes less power than a single x1900xt, x1900xtx, or x1950xtx, the g71 runs cooler, and a single 7950GX2 has a large performance advantage.

Originally Posted by Nistomax

Very nice guide Turok.
I use a BFG tech 7950 and it runs like a dream. I only use 1280x1024 but i plan on getting a 24" Acer monitor soon. I'll try to review it for the guide, but my knowlege of computers is limited compared to the gurus of XS. I'll post in the guide if/when I get it.

My suggestions for the guide:
Make it more obvious that the 7950 is only supported on some motherboards. I get the impression that nvidia isnt going to help you if your card isnt on the list...

I wouldnt recommend Acer's LCDs

Some of their large widescreen LCDs use VGA connectors and other have huge pixel pitch or lower native resolutions (like a TV). Their overall construction grade isnt too good either

I would recommend a Dell 2407fpw Rev.02 for around $800 or a bit less.
Im planning on getting a 2407fpw Rev.02 for my self.
If you get a Rev.02 LCD, it should not have color banding and text blurryness.

As for the mobo compatibility, I think any mobo with the same chipset as other mobos tested on that list should work with a single 7950GX2.
I also think it should work on any PCI-E mobo because everything from the PCI-E slot goes through the SLI controller on the 7950GX2
But I will add something like "(but check for compatibility just to be safe)" anyway

**mdzcpa** · 08-21-2006, 02:12 PM

Has anyone gotten Quad SLI to work properly on an Intel 975 board? I know a few folks have experimented with it...I am referring to it actually working correctly with good performance.

**gelatinousfury** · 08-21-2006, 04:10 PM

Very informative Turok!!! Awesome

**Hicks** · 08-22-2006, 06:21 AM

I would keep it Turok, but i really really don't like the drivers. And god dam shimmering in Far Cry ive seen aready.

Got an RMA number, it's going back 2moro.

**Artmic** · 08-25-2006, 08:15 PM

This might be a funny question, but how do i know my 7950 is working properly on an Asus P5W DH board? I mean the SLI functionality of it, it works in single vid card mode since i can boot up and go into windows, i'm just thinking if the SLI feature works fine.

**Turok** · 08-26-2006, 01:30 PM

Originally Posted by Artmic

This might be a funny question, but how do i know my 7950 is working properly on an Asus P5W DH board? I mean the SLI functionality of it, it works in single vid card mode since i can boot up and go into windows, i'm just thinking if the SLI feature works fine.

Do you mean Quad-SLI vs a single 7950gx2?
The only way to know is by benchmarking with a single 7950GX2 and then with the second 7950GX2 and see how performance changes.
Quad-SLI drivers still need some work, but the best drivers for now is FW 91.45 Beta. If you have a performance decrease, it could be CPU bottleneck or that the drivers need some work or you may need to try another Quad-SLI profile on your settings.
Try to run at very GPU dependent settings so its easier to view the difference.
e.g.: Counter Strike Source's Militia map with HDR on, all settings maxed, 8xTSAA or higher, 16xAF, and a resolution above 1600x1200.
At such settings, if you dont see a performance gain over a single 7950GX2 or if your performance decreases, then you should wait for better drivers or try another profile.
If you get like a 10% increase, at least that's better than nothing or less

In that case if you cant do anything else to optimize it because SLI drivers need some optimization, then stay with Quad-SLI and always run at GPU dependent settings.

**Artmic** · 08-26-2006, 07:18 PM

Originally Posted by Turok

Do you mean Quad-SLI vs a single 7950gx2?
The only way to know is by benchmarking with a single 7950GX2 and then with the second 7950GX2 and see how performance changes.
Quad-SLI drivers still need some work, but the best drivers for now is FW 91.45 Beta. If you have a performance decrease, it could be CPU bottleneck or that the drivers need some work or you may need to try another Quad-SLI profile on your settings.
Try to run at very GPU dependent settings so its easier to view the difference.
e.g.: Counter Strike Source's Militia map with HDR on, all settings maxed, 8xTSAA or higher, 16xAF, and a resolution above 1600x1200.
At such settings, if you dont see a performance gain over a single 7950GX2 or if your performance decreases, then you should wait for better drivers or try another profile.
If you get like a 10% increase, at least that's better than nothing or less

In that case if you cant do anything else to optimize it because SLI drivers need some optimization, then stay with Quad-SLI and always run at GPU dependent settings.

Hmmm, i'm not interested in quad yet, i think it is overkill for my needs.

I mean i have one 7950 video card in my system, and i am just interested to know if for example 3Dmark05/06 uses both gpu's on the 7950 or just one?
I guess i want to feel like i purchased something for a billion dollars and it actually works

**SlicerSV** · 08-26-2006, 07:44 PM

Originally Posted by Artmic

I mean i have one 7950 video card in my system, and i am just interested to know if for example 3Dmark05/06 uses both gpu's on the 7950 or just one?

uhm, my understanding, reading post #1, is that you should already be using both GPU's on the GX2 automagically. the GPU linking is done entirely within the two cards, and it shown to the system as a single card.

**gr8golf** · 08-26-2006, 10:15 PM

Can anyone comment on how much noise the 7950's put out compared to the 7900GTX's, or the 7800 / 7900 GT's? I am back to my 7800GT with the Arctic Cooling Silencer. It is basically silent. The 7900GTX I ran for a couple months was also basically silent, and really quite a good card.

**Artmic** · 08-27-2006, 07:13 AM

Originally Posted by SlicerSV

uhm, my understanding, reading post #1, is that you should already be using both GPU's on the GX2 automagically. the GPU linking is done entirely within the two cards, and it shown to the system as a single card.

I see, so in otherwords it is on always, unless a game can't utilize it. i downloaded that nHancer utility, don't know what to do with it. lol

**Turok** · 08-27-2006, 11:01 AM

Originally Posted by Artmic

Hmmm, i'm not interested in quad yet, i think it is overkill for my needs.

I mean i have one 7950 video card in my system, and i am just interested to know if for example 3Dmark05/06 uses both gpu's on the 7950 or just one?
I guess i want to feel like i purchased something for a billion dollars and it actually works

Oh, I just assumed you were talking about two 7950GX2 on SLI, since you said "SLI functionality"

In that case you could use the ORB (Futuremark/3DMark) to help you out. Find someone with a simmilar setup with a stock 7900GT or GTX.
If its running in single-mod, then the score should be higher than the GT, but lower than the GTX.
But if its on SLi mod, it should be in between 2x GT's and 2x GTX's or equal to the average of a stock GX2.
Make sure to use a GPU dependent 3DMark to get more accurate scores. Either 3DMark 05 or 06.

Originally Posted by SlicerSV

uhm, my understanding, reading post #1, is that you should already be using both GPU's on the GX2 automagically. the GPU linking is done entirely within the two cards, and it shown to the system as a single card.

Nope. The cards can run in single mod, and it seemed that way when I had the wrong drivers and the wrong settings.
Although it has the SLI controller on the video card instead of the motherboard, it still needs the drivers to unite them. Otherwise they wont know how to work together.
I havent tryed it, but Im sure if I disable SLI mod on my driver settings my card will have a performance in between a single 7900GT and 7900GTX.

Originally Posted by gr8golf

Can anyone comment on how much noise the 7950's put out compared to the 7900GTX's, or the 7800 / 7900 GT's? I am back to my 7800GT with the Arctic Cooling Silencer. It is basically silent. The 7900GTX I ran for a couple months was also basically silent, and really quite a good card.

Well, I updated from a x850xt and believe it or not the ATi cooler is louder

The cards are pretty silent IMO. Dont know what else to compare it to, tho :P

**Baraka** · 08-27-2006, 11:37 AM

Thought i'd add some info on monitoring temps and controlling/monitoring the fan speeds on this card.

My card is a Leadtek WinFast PX7950GX2.

What I have found so far:

Rivatuner:
can monitor clock and temp of 1 core (the outer one)
can control driver level fan speeds (2D/3D) (both fans change)
does not display fan speeds
does not correctly display fan duty cycle (stuck @ 100% all time)

Everest:
can display both core temps.

Will add some more later.......

I thought this might be interesting as different brands seems to work differently. I remember seeing a post somewhere: the guy was getting both fan speeds reported in Everest but when changing fan speeds with Rivatuner only one fan would actually change