a call for some who has both 7900GT's & 7950GX2...

[naelq]

i've been looking for a real comparo between the 7950GX2 & 2x 7900GT's in SLI, testing the following:

1. a comparo running the 7900GT's in SLI with the SAME speeds as the 7950GX2
2. a comparo running the 7950GX2 @ Max OC & 7900GT's Max OC. (stock without any vmoding! :D)

since i'm pretty sure there are many people with the same situation like me, i've already got the Waterblocks (Maze4 Acetal) & planing to get the cards next week! :rolleyes:

so can you please contribute? :)

[[XC] DragonOrta]

Can you water cool more than one of the 7950GX2 GPUs?

[naelq]

this is the :banana::banana::banana::banana:ing problem!!! i already bought the Maze4's... i'm pretty sure that there will be WB for the 7950 (& i have no problem building my own) but still, i have 3 Maze4's!! 2x brand new acetals & 1x of the old revision!!

ayway, i think that the GT's have a better chance to OC, but i would like to see some numbers. :rolleyes:

[Turok]

hmmm... this thread could be interresting.

2x 7900GT (512mb total) costs about $480-$500
1x 7950GX2 (1Gb total) costs about $550
Only problem is that people like me will need to get a SLI mobo for 2x7900GT :(
A single 7950GX2 can run even in mobos with Intel and ATi chipsets.

There are some benchmarks where the 7950GX2 comes close to 2x7900GT SLI, and in others it comes close to 2x 7900GTX.
I would like to see some comparisons with the newest drivers that give full compatibility for a single 7950GX2 to see if its closer to the GTX than the GT.

Closer to GTX
http://www.xbitlabs.com/images/video/nvidia-gf7950gx2/games/fear_4x.gif

Closer to GT
http://www.xbitlabs.com/images/video/nvidia-gf7950gx2/games/tesout_hdr.gif

It would also be interresting to know which one draws more power
2x7900GT or a single 7950GX2

BTW, which ones are the 7900GT with the bad capacitors that kill the card?
I know its the ones with purple capacitors have it fixed, but which companies/models are guaranteed to have this fixed?

[Turok]

I found the answer to some of my questions in Anandtech.
http://www.anandtech.com/video/showdoc.aspx?i=2769&p=9

2x7900GT on SLI consumes less power than a single 7950GX2
http://images.anandtech.com/graphs/7950gx2_06040690609/12204.pnghttp://images.anandtech.com/graphs/7950gx2_06040690609/12205.png


1. a comparo running the 7900GT's in SLI with the SAME speeds as the 7950GX2
I think this chart will answer your first question, because the specs are about the same between the 7900GT and 7950GX2 except for the memory size. In the benchmarks, the 7950GX2 seems to perform a lot better, so the core may be better.
The 7950GX2 could be more like a underclocked 7900GTX to around 7900GT levels.
The 7950GX2 will probably overclock higher with some volt modding and proper cooling (I think)
http://img233.imageshack.us/img233/5122/chart5jl.jpg


In most benchmarks, the 7950GX2 seems to stay ahead with a large gap, while 2x 7900 GT on SLI somestimes fall behind even under single card resolutions in GPU dependent resolutions. And these are not even the drivers that give 7950GX2 compatibility
Example:
http://images.anandtech.com/graphs/7950gx2_06040690609/12181.pnghttp://images.anandtech.com/graphs/7950gx2_06040690609/12183.png


The memory size should also be taken into consideration, since it allows the 7950GX2 to gain huge performance at really high resolutions with low compressions.
http://images.anandtech.com/graphs/7950gx2_06040690609/12165.png

[naelq]

ok, SLI MoBo? how about modding your Ultra-D (if it's from the old batces, you you can do it for sure :))

i've been analysing the 7950GX2 reviews, especially AT's one for a while. the weird thing is that both the 7900GT/GTX/7950GX2 have the same G71 core (right?) but their clocks are different.
now the question would be, why does the 7950GX2 get better scores than 2x 7900GT in SLI? it must be one of the following:
1. the extra 30MHz on each core?
2. the OnBoard 'SLI' bridge on the 7950 is better than the nFroce4's SLI? (i didn't see any reviews based on nForce 570/590)
3. or simply the drivers are built to push the 7950 ;)

eh?

[mdzcpa]

4. 256 versus 512 mb frame buffer per core.
5. Mem clock speeds

1,2,4,5 apply.


Cooling is the only real issue on the 7950. There are a few things in the pipeline from what I've been hearing. Even so, these 7950s oc pretty darn well on air alone. I've yet to see a pair of GTs in SLI (regardless of cooling) touch 7950 performance. "Close" in some benches is about as good as it gets for the GTs, while the the 7950 gets close to a pair of GTXs in others.

The decent power consumption, quiet operation, and no SLI mobo requirement make this an easy choice IMO. The 7950 is a nice way to get SLI performance on the upcoming Intel mobos without hacked drivers. Not to mention the possibility of going quad SLI for those with SLI chipsets.

FYI, my 7900GTs went bye bye i favor of the 7950. Better performance....not too mention it works great on my bad axe mobo:)

[naelq]

256MB vs. 512MB? hmmm, interesting.

mem clock speeds? in this case, it should be the opposite! since the 7900GT is the one with 660MHz vs. the 600MHz a 7950GX2 has. :rolleyes:

anyway, it seems that i must sell those Maze4 pupies! :D

[Turok]

True. The chipset, memory timmings, and memory size are probably the biggest cause for the performance advantage on the 7950GX2 vs 2x7900GX2.
If the memory is the same as the 7900GTX, then it could have potential of reaching 7900GTX speeds in memory.

I think the 7950GX2 is limited in voltage more than anything else to make the cards cooler.
Here's the default vMem and vGPU ratting on each video card:

7900GT:
vGPU = 1.2v (2D & 3D mods)
vMem = 2.02v (constant)

7900GTX:
vGPU = 1.4v (3D mod)
vMem = 2.12v (constant)

7950GX2:
vGPU = 1.3v (3D mod)
vMem = 1.92v (constant)

Its interresting to see how vGPU is in between the 7900GT and 7900GTX, while the vMem is lower than both.

Im sure with some simple volt mods, and better cooling, the 7950GX2 can perform at 2x 7900GTX levels and better.
Here's a guide for volt modding the 7950GX2:
http://sg.vr-zone.com/index.php?i=3659

I guess Im set to updating to a single 7950GX2, but the watercooling method is still unknown.
I guess Ill have to wait for the Aqua-Computer waterblock or I will have to find someone who can make me a custom copper waterblock with 1/2" fittings ;)
A pair of the Termaltake pure copper waterblocks of their 7950GX2 watercooling solutions could work, but I dont know if they will be restrictive or horrible performers for my 1/2" watercooling loop.

[mdzcpa]

Turok,

Just a quick note to mention that you presented some great analysis on this thread. Well done.

[pissboy]

Can you water cool more than one of the 7950GX2 GPUs?

There was a guy on the sudhain forums who watercooled the GPUs on his Shuttle SN26P, cooling those should be just as easy (difficult). :D

(koolance) http://www.kmdevelopment.com/graphics/graphics_misc/SLi_7900GTs.jpg

[moguy99]

Posted this in some other threads, but it's sorta relevant to this discussion, I guess:

http://www.evga.com/community/messageboard/topic.asp?TOPIC_ID=17021

http://hell.tc/dnn/

[naelq]

thanks for the input moguy99, but it seems that i'm going the 7900GTX SLI route :D

[daffy67]

What rig u using now??:)

[naelq]

What rig u using now??:)
is it the same 'ol daffy fron TA?? :)

[Turok]

thanks for the input moguy99, but it seems that i'm going the 7900GTX SLI route :D

I wouldnt recommend that.
The 7950GX2 is a lot cheaper and it has the potential of reaching 2x 7900GTX SLI speeds.

I also do not recommend buying a 7900GTX because they seem to die in a short time like the 7900GT. It may be because of the same capacitor problems in the 7900GT.

Right now Im trying to find a solution to cool the 7950GX2 with a high performance 1/2" fitting copper waterblock with the help of some CNC waterblock builders. I may buy the 7950GX2 verry soon since its really cheap, and so I can make some precise measurements for the block builders.
http://www.xtremesystems.org/forums/showthread.php?t=104693

You can get a XFX 7950GX2 (520/1300) for $540. Check out this thread:
http://www.xtremesystems.org/forums/showthread.php?t=105317
I may get one verry soon considering how cheap it is.
Im upgradeing from my x850xt to this afther a year of use.
Its going to be like almost tripling the video card power I currently have for about the same price of what a x850xt-PE costed a year ago, and on top of that I will be able to play in SM3 mod. :slobber: Amazing how technology is evolving these days :D

[Celcius]

I agree with Turok. The 7900GTX's seem to die just as easily as the 7900GT's. I think you'll end up getting the best performance out of the 7950GX2. Plus, when nvidia releases the driver, you could add a second one for quad-sli.:D

[naelq]

for the regular customer, it's true the 7950GX2 is cheaper, but for someone who sell thses stuff, 7900GTX, they are so cheap ;)
TBH, the only thing prenting me from getting the 7950GX2 is the W/C thing...
need to decide!

[Marioace]

i've been looking for a real comparo between the 7950GX2 & 2x 7900GT's in SLI, testing the following:

1. a comparo running the 7900GT's in SLI with the SAME speeds as the 7950GX2
2. a comparo running the 7950GX2 @ Max OC & 7900GT's Max OC. (stock without any vmoding! :D)

since i'm pretty sure there are many people with the same situation like me, i've already got the Waterblocks (Maze4 Acetal) & planing to get the cards next week! :rolleyes:

so can you please contribute? :)
This is from a review
http://www.madboxpc.com/contenido.php?id=2225

the clocks for the 7900GT's are 470/1300Mhz

http://img117.imageshack.us/img117/7797/14id.png
http://img92.imageshack.us/img92/6227/25tu.png

oblivion interiors
http://img301.imageshack.us/img301/6777/34xd.png

oblivion exteriors
http://img238.imageshack.us/img238/6996/44de.png

[Jotequila]

This is from a review
http://www.madboxpc.com/contenido.php?id=2225

the clocks for the 7900GT's are 470/1300Mhz

http://img117.imageshack.us/img117/7797/14id.png
http://img92.imageshack.us/img92/6227/25tu.png

oblivion interiors
http://img301.imageshack.us/img301/6777/34xd.png

oblivion exteriors
http://img238.imageshack.us/img238/6996/44de.png


that review kicks ass :D

[daffy67]

is it the same 'ol daffy fron TA?? :)
:yepp: :)

[naelq]

@ Marioace, good review but i was looking with a review of 7900GT SLI'd @ GX2's speeds ;)

@daffy, you've PM :toast:

[Turok]

@ Marioace, good review but i was looking with a review of 7900GT SLI'd @ GX2's speeds ;)

@daffy, you've PM :toast:

A regular 7950GX2 has clock speeds of 500/1200 per card
A regular 7900GT is clocked at about 450/1360 per card.
Clock speeds are about the same, but if you look at some benchmarks (Like Anandtech's) you can see how the 7950GX2 pulls ahead probably due to the larger and superior memory from the GTX, and the SLI Controller on the 7950GX2 probably works better than letting the chipset do the work.

Well, this is just repearting what I said above.
If you can get 2x 7900GTX really cheap, then go ahread,
but I would recommend going to a single 7950GX2 and overclocking it with custom waterblocks if your 7900GTXs die.


@Marioace & Jotequila

Those benchmarks dont look too good for comparison...
This is their test setup:

Hardware:

AMD Athlon 64 FX-62 Socket AM2
Asus M2N32SLI-Deluxe Bios 0504
2x512MB Corsair XMS2 PC2 8500
1x Gigabyte 7900GTX 512MB GDDR3
2x XFX 7900GT 256MB GDDR3
2x XFX 7950GX2 Extreme Edition
Western Digital 120GB Sata
Thermaltake ToughPower 600W

They are compareing 2x 7950GX2 with a single 7900GTX and 2x 7900GT.
2x 7950GX2 are a huge bottleneck for the CPU, so in some situations its going to perform lower or pretty much the same to the 7950GX2 in most cases since the drivers still need some work.

I wouldnt expect a single 7900GTX to perform so close to 2x 7900GT. By looking at the high FPS, it looks like they used high settings in a low resolutions, which makes it less GPU dependent and puts the scores about the same.

I would expect those scores on the Oblivion out-door benchmarks, tho.
In outdoors it stresses the whole system, so the GPUs go down with the system aswel, which reduces the gap between the cards. If they had a setup with 2Gb of ram, then the gap would of probably been a bit larger.

Overall, those benchmarks are not so good for comparisons (IMO)

[Marioace]

@Marioace & Jotequila

Those benchmarks dont look too good for comparison...
This is their test setup:


They are compareing 2x 7950GX2 with a single 7900GTX and 2x 7900GT.
2x 7950GX2 are a huge bottleneck for the CPU, so in some situations its going to perform lower or pretty much the same to the 7950GX2 in most cases since the drivers still need some work.

I wouldnt expect a single 7900GTX to perform so close to 2x 7900GT. By looking at the high FPS, it looks like they used high settings in a low resolutions, which makes it less GPU dependent and puts the scores about the same.

I would expect those scores on the Oblivion out-door benchmarks, tho.
In outdoors it stresses the whole system, so the GPUs go down with the system aswel, which reduces the gap between the cards. If they had a setup with 2Gb of ram, then the gap would of probably been a bit larger.

Overall, those benchmarks are not so good for comparisons (IMO)
yes that is the Setup, but the Graphs are with ONE 7950GX2 no Quad SLI

so the Bottleneck is the same for 7900GT SLI and the 7950GX2 "single"

[CedricFP]

Damn, the 7950GX2 costs less than what I bought my XTX for!!

[Blacklash]

I have the Evga brand 7950 GX2 so I am covered with step-up. If anything comes out better than it in the next 90days, boo yah! I can trade it in for credit vs that card.

Mine does the top XFX speeds np, or 571|775. I haven't gone beyond that yet and don't feel the need to. If you play 1600x or greater with AA|AF active it's an awesome card and worth the price. It's a great way to essentially get 512mb GT SLi on an Intel platform.

If you went X1900 XT Crossfire today instead you would be paying almost 300 dollars more. Last I checked the 7950 GX2 could be had for around 559usd at the Egg, and X1900 XT Crossfire was a total of 848usd from the same. So almost 290 separating them.