GeForce 9800GTX Tri-SLi versus GeForce 9800GX2 SLi - Who is the Winner Here?

[AuDioFreaK39]

I had an interesting question posed on me the other night regarding whether a Tri-SLi 9800GTX configuration would outperform an SLi 9800GX2 configuration, or if it would be the other way around. I thought it was a very controversial argument, and so I eventually came up with two of my own opinions on the subject matter:

The 9800GX2 is comprised of the same chips used in the G92 8800GTS (see here). Therefore, it's a tough call whether a Tri-SLi 9800GTX setup will outperform the 9800GX2 - seems very reasonable. Here are the possibilities to consider:

1) Nvidia developed the 9800GX2 under the premise that it would be thee world's fastest graphics card, for the time being, until GT200 is out. And under that premise, they want their consumer base to have more expandability options (Quad-SLi), but at a sacrifice of expandability comes a sacrifice of performance, and therefore 9800GTX Tri-SLi is better.

2) Nvidia is asserting that two 9800GX2s in Quad-SLi will always give you top-notch performance for the current generation cards, and three 9800GTXs in Tri-SLi is the next step down for those with Tri-SLi supporting motherboards. Therefore, in this case, it would be logical to assume that three 9800GTXs ARE NOT better than two 9800GX2s.

If I were to choose a side, I would pick possibility number 2. Any well-thought arguments and opinions are welcome.

 

[n7]

Not sure this is overly complicated.

SLI 9800 GTX > 9800GX2
SLI 9800 GX2 > tri-SLI 9800 GTX

Of course this is dependent on games that actually scale with SLI, & there are a lot more that don't than you'd believe.
All you need to do is look at how the majority of review sites use the exact same games for their reviews.

Then you have the less mainstream sites using "odd" games which don't show very positive results.

 

[ghost recon88]

2x 9800GX2s are faster then Tri-SLI. The more physical cards you add to the scenario, the less performance scaling you get. Also keep in mind that the GX2 in SLI has 4 GPUs while the GTXs in Tri-SLI only have 3 GPUs.

 

[Valconian]

We've seen the fall of the very first GX2, the 7950. Thou a single 7950GX2 performance is almost on par with 8800GTS G80, twinning the cards did not benefit due to the limitation of the Operating System. As most gamers still prefers to game on Windows XP, Vista is the only platform that could benefit from a four-core gpu rendering.

This applies the same to 9800GX2. Only Vista can unlock the full potential of 4-core gpu. If one has got no plans to go Vista, IMO, 9800GTX Tri SLi would be a better option.

 

[CSQuake]

Very interesting debate.

However, with tri-Sli boards, does this mean you need to throw tri-GX2 into the equation?

 

[imported_wired247]

Originally posted by: ghost recon88
2x 9800GX2s are faster then Tri-SLI. The more physical cards you add to the scenario, the less performance scaling you get. Also keep in mind that the GX2 in SLI has 4 GPUs while the GTXs in Tri-SLI only have 3 GPUs.

I think the main purpose of going with more video cards is not necessarily to help boost average FPS, since as you say scaling does not get much better,

but to prevent slow down during heavy loads ... right? (Not 100% sure about this)

 

[Valconian]

Originally posted by: CSQuake
Very interesting debate.

However, with tri-Sli boards, does this mean you need to throw tri-GX2 into the equation?

9800GX2 cannot support Tri SLi as it only has one gold-finger (aka SLi connector). At this point of time, only 3 types of cards supports Tri SLi; 8800GTX, 8800 Ultra & 9800GTX.

 

[djnoob]

You can't throw tri-SLI gx2 into the equation becuase it's not possible. If you look at the architecture of TRI-SLI you'll see that these cards can't support it. There is one thing that might be able to do it and that is Skulltrail. I saw an interview with I believe the head of the skulltrail project and he stated that he had a rig in the lab that was running both crossfire and sli at the same time! If that's true, then I do wonder if it might be possible to run 4 gx2's on this board. If I remember correctly, the skulltrail board doesn't actually require a sli bridge because sli is controled by the additional chips on the board. I'd love someone to be able to chime in on that one.

Back to topic, someone stated already that with quad sli there are 4 processors and with tri sli there are only three. Good point. Aslo with quad you've got 2gb of memory where as with tri-sli 9800 gtx's you'll only have 1.5gb.

Now the clock speeds on the gtx are a bit higher but not enough I think to really make that much of a difference. (plus the gx2's seem to overclock extremely well) However, looking at previous releases of cards, you'll have companies factory overclocking the gtx's and who knows, maybe we'll see a 9800 ultra with substantialy greater clock speeds and additional memory. This does though seem like alot of releases in a short period of time with the r200 supposedly just around the corner. Somehow though I imagine that ultra's are in fact in development and Nvidia might just be waiting to see what ATI pulls out of their hat. Hence if ATI can't answer the 9800 series then they prolong the life of the series by releasing and ultra, just to stay on top. However if ATI releases something pretty good, then they go ahead with the r200 launch.

I think for now quad sli with be on top provided they get the drivers right and not end up with another 7950 mess. This however is in the short term. At this point I think what we're all trying to figure out (and Nvidia has been very tight lipped as of late) is not if, but when they will release something far better.

 

[mwmorph]

Originally posted by: djnoob
You can't throw tri-SLI gx2 into the equation becuase it's not possible. If you look at the architecture of TRI-SLI you'll see that these cards can't support it. There is one thing that might be able to do it and that is Skulltrail. I saw an interview with I believe the head of the skulltrail project and he stated that he had a rig in the lab that was running both crossfire and sli at the same time! If that's true, then I do wonder if it might be possible to run 4 gx2's on this board. If I remember correctly, the skulltrail board doesn't actually require a sli bridge because sli is controled by the additional chips on the board. I'd love someone to be able to chime in on that one.

Back to topic, someone stated already that with quad sli there are 4 processors and with tri sli there are only three. Good point. Aslo with quad you've got 2gb of memory where as with tri-sli 9800 gtx's you'll only have 1.5gb.

Now the clock speeds on the gtx are a bit higher but not enough I think to really make that much of a difference. (plus the gx2's seem to overclock extremely well) However, looking at previous releases of cards, you'll have companies factory overclocking the gtx's and who knows, maybe we'll see a 9800 ultra with substantialy greater clock speeds and additional memory. This does though seem like alot of releases in a short period of time with the r200 supposedly just around the corner. Somehow though I imagine that ultra's are in fact in development and Nvidia might just be waiting to see what ATI pulls out of their hat. Hence if ATI can't answer the 9800 series then they prolong the life of the series by releasing and ultra, just to stay on top. However if ATI releases something pretty good, then they go ahead with the r200 launch.

I think for now quad sli with be on top provided they get the drivers right and not end up with another 7950 mess. This however is in the short term. At this point I think what we're all trying to figure out (and Nvidia has been very tight lipped as of late) is not if, but when they will release something far better.

It still would not be possible to do 6xsli(that's essentially what the 9800GX2 would be), it's driver related. No driver SLI profile = no performance gain.

As for whoever said performance gain decreases with physical cards, that just plain doesn't make sense. Performance gain decreases as additional CORES are added so the 4th gpu in 2x 9800GX2 would be less of a boost than the 3rd in the 9800GTX percentage wise.

As for memory, you cant look at it like that. Both options provide 512mb of available framebuffer VRAM. The same data is essentially copied to all 3 or 4 cards because they don't "share" memory and data between cores.

In the end it all depends on how much faster a single 9800GTX core is in comparison to a Single 9800GX2 core and how much(or little) the 4th core provides performance wise.

3 9800GTX could be faster than 2 9800GX2 if the 9800GTX core for core is faster enough than a 9800GX2 core.


Think of it like this, 4 family sedan(GX2)s and 3 minivans(GTX) are trying to carry the same number of people to a destination (lets say 300)

They all have gas in the fuel tank (VRAM) that gets used up at the same rate but don't span across all 3 or 4 vehicles. We're not pulling any miracles here, the 3 cars wont all drive 20 miles on the same gallon of gasoline, each car uses a gallon of gasoline per 20 miles so in the end, 150 and 200 gallons of gasoline help the 3 vans or 4 cars respectively travel the same distance.

Now it if you can cram enough people in the vans, the Tri-SLi GTX could quite possibly be quicker in transporting every single person to the destination.

 

[djnoob]

Originally posted by: mwmorph

Originally posted by: djnoob
You can't throw tri-SLI gx2 into the equation becuase it's not possible. If you look at the architecture of TRI-SLI you'll see that these cards can't support it. There is one thing that might be able to do it and that is Skulltrail. I saw an interview with I believe the head of the skulltrail project and he stated that he had a rig in the lab that was running both crossfire and sli at the same time! If that's true, then I do wonder if it might be possible to run 4 gx2's on this board. If I remember correctly, the skulltrail board doesn't actually require a sli bridge because sli is controled by the additional chips on the board. I'd love someone to be able to chime in on that one.

Back to topic, someone stated already that with quad sli there are 4 processors and with tri sli there are only three. Good point. Aslo with quad you've got 2gb of memory where as with tri-sli 9800 gtx's you'll only have 1.5gb.

Now the clock speeds on the gtx are a bit higher but not enough I think to really make that much of a difference. (plus the gx2's seem to overclock extremely well) However, looking at previous releases of cards, you'll have companies factory overclocking the gtx's and who knows, maybe we'll see a 9800 ultra with substantialy greater clock speeds and additional memory. This does though seem like alot of releases in a short period of time with the r200 supposedly just around the corner. Somehow though I imagine that ultra's are in fact in development and Nvidia might just be waiting to see what ATI pulls out of their hat. Hence if ATI can't answer the 9800 series then they prolong the life of the series by releasing and ultra, just to stay on top. However if ATI releases something pretty good, then they go ahead with the r200 launch.

I think for now quad sli with be on top provided they get the drivers right and not end up with another 7950 mess. This however is in the short term. At this point I think what we're all trying to figure out (and Nvidia has been very tight lipped as of late) is not if, but when they will release something far better.

It still would not be possible to do 6xsli(that's essentially what the 9800GX2 would be), it's driver related. No driver SLI profile = no performance gain.

As for whoever said performance gain decreases with physical cards, that just plain doesn't make sense. Performance gain decreases as additional CORES are added so the 4th gpu in 2x 9800GX2 would be less of a boost than the 3rd in the 9800GTX percentage wise.

As for memory, you cant look at it like that. Both options provide 512mb of available framebuffer VRAM. The same data is essentially copied to all 3 or 4 cards because they don't "share" memory and data between cores.

In the end it all depends on how much faster a single 9800GTX core is in comparison to a Single 9800GX2 core and how much(or little) the 4th core provides performance wise.

3 9800GTX could be faster than 2 9800GX2 if the 9800GTX core for core is faster enough than a 9800GX2 core.


Think of it like this, 4 family sedan(GX2)s and 3 minivans(GTX) are trying to carry the same number of people to a destination (lets say 300)

They all have gas in the fuel tank (VRAM) that gets used up at the same rate but don't span across all 3 or 4 vehicles. We're not pulling any miracles here, the 3 cars wont all drive 20 miles on the same gallon of gasoline, each car uses a gallon of gasoline per 20 miles so in the end, 150 and 200 gallons of gasoline help the 3 vans or 4 cars respectively travel the same distance.

Now it if you can cram enough people in the vans, the Tri-SLi GTX could quite possibly be quicker in transporting every single person to the destination.

LOL great analogy.

As far as the # of cores, yeah it's a decreasing rate of return.

I would agree your other point and that was kind of what I was saying. Looking at the specs for the gtx, I don't see that 3 of them would faster enough to beat two gx2's. However, if they release an ultra with significantly higher clocks well then we might have a challenger.

 

[mwmorph]

Originally posted by: djnoob

Originally posted by: mwmorph

Originally posted by: djnoob
You can't throw tri-SLI gx2 into the equation becuase it's not possible. If you look at the architecture of TRI-SLI you'll see that these cards can't support it. There is one thing that might be able to do it and that is Skulltrail. I saw an interview with I believe the head of the skulltrail project and he stated that he had a rig in the lab that was running both crossfire and sli at the same time! If that's true, then I do wonder if it might be possible to run 4 gx2's on this board. If I remember correctly, the skulltrail board doesn't actually require a sli bridge because sli is controled by the additional chips on the board. I'd love someone to be able to chime in on that one.

Back to topic, someone stated already that with quad sli there are 4 processors and with tri sli there are only three. Good point. Aslo with quad you've got 2gb of memory where as with tri-sli 9800 gtx's you'll only have 1.5gb.

Now the clock speeds on the gtx are a bit higher but not enough I think to really make that much of a difference. (plus the gx2's seem to overclock extremely well) However, looking at previous releases of cards, you'll have companies factory overclocking the gtx's and who knows, maybe we'll see a 9800 ultra with substantialy greater clock speeds and additional memory. This does though seem like alot of releases in a short period of time with the r200 supposedly just around the corner. Somehow though I imagine that ultra's are in fact in development and Nvidia might just be waiting to see what ATI pulls out of their hat. Hence if ATI can't answer the 9800 series then they prolong the life of the series by releasing and ultra, just to stay on top. However if ATI releases something pretty good, then they go ahead with the r200 launch.

I think for now quad sli with be on top provided they get the drivers right and not end up with another 7950 mess. This however is in the short term. At this point I think what we're all trying to figure out (and Nvidia has been very tight lipped as of late) is not if, but when they will release something far better.

It still would not be possible to do 6xsli(that's essentially what the 9800GX2 would be), it's driver related. No driver SLI profile = no performance gain.

As for whoever said performance gain decreases with physical cards, that just plain doesn't make sense. Performance gain decreases as additional CORES are added so the 4th gpu in 2x 9800GX2 would be less of a boost than the 3rd in the 9800GTX percentage wise.

As for memory, you cant look at it like that. Both options provide 512mb of available framebuffer VRAM. The same data is essentially copied to all 3 or 4 cards because they don't "share" memory and data between cores.

In the end it all depends on how much faster a single 9800GTX core is in comparison to a Single 9800GX2 core and how much(or little) the 4th core provides performance wise.

3 9800GTX could be faster than 2 9800GX2 if the 9800GTX core for core is faster enough than a 9800GX2 core.


Think of it like this, 4 family sedan(GX2)s and 3 minivans(GTX) are trying to carry the same number of people to a destination (lets say 300)

They all have gas in the fuel tank (VRAM) that gets used up at the same rate but don't span across all 3 or 4 vehicles. We're not pulling any miracles here, the 3 cars wont all drive 20 miles on the same gallon of gasoline, each car uses a gallon of gasoline per 20 miles so in the end, 150 and 200 gallons of gasoline help the 3 vans or 4 cars respectively travel the same distance.

Now it if you can cram enough people in the vans, the Tri-SLi GTX could quite possibly be quicker in transporting every single person to the destination.

LOL great analogy.

As far as the # of cores, yeah it's a decreasing rate of return.

I would agree your other point and that was kind of what I was saying. Looking at the specs for the gtx, I don't see that 3 of them would faster enough to beat two gx2's. However, if they release an ultra with significantly higher clocks well then we might have a challenger.

Looking at 3 and 4 way crossefirX benchmarks for the 9800GTX to be faster than the 9800GX2 setup in all games would require a 14% per core increase in performance. OF course that's not representative of Nvidia SLi but it's as close as we can get until more benchmarks come out.

I have no clue how fast 9800GTX will be but I dont think it'll reach 14%. Overclocked Tri-Sli will most likely or probably even be guranteed be able to best stock Quad-SLI, but i agree, I don't think stock v.s. stock it has a chance. Performance won't be too far behind though and Tri-SLI si bound to be faster in some games that arent Tri/QuadSLI.

Off topic though, Nvidia needs a new name for it. CrossfireX rolls off the tounge. Tri and Quad SLi... I'm tired of typing it.

 

[djnoob]

ROFL True dat. SLI was fine but now they're complicating things.

You talk about overclocking though, the gx2's overclock very well. I've been able to run mine 20% overclock without even really trying. From what I hear, overclocked gx2's are just around the corner. So it would be a overclocking battle which the gtx's might win because of the individual pcb's. Even if you water cool them, cooling should be better for the gtx's. One way or another it's going to be close between the two.

All I got to say though is that those quad-sli drivers better work or this discussion is a mute point.

Here's another point that I hadn't thought about.....

3 gtx's = $1050
2 gx2's = $1200

Would they really allow the tri-sli gtx's to be faster?

 

[CSQuake]

Moving the debate further forward in terms of future products, what are the next products from ATI and Nvidia after the ATI 3 series and the Nvidia 9 series? I'm trying to work out if it's worth upgrading my GFX now'ish or in a few months.

 

[djnoob]

Originally posted by: CSQuake
Moving the debate further forward in terms of future products, what are the next products from ATI and Nvidia after the ATI 3 series and the Nvidia 9 series? I'm trying to work out if it's worth upgrading my GFX now'ish or in a few months.

At this point it's difficult to discuss. Yes new cards will come out but there's really no way of knowing when they will actually be released. Both Nvidia and ATI, well just about every tech company for that matter, have a lovely habit of pushing out lanches. I don't think we really have enough info to work with.

Man if you're running a 7 seried or lower then just upgrade now. If you're running 8800's of some sort and you don't upgrade every year, it might be worth it to just wait. Just realize that you might be waiting until next year to get something new.

 

[PCTC2]

6 SLI = HEX-L-I! LOL.

Sorry for the nef but I couldn't help myself.

EDIT: Oh yeah, and I'm going for Tri-SLI and Tri-Fire.
3x 9800GTX on an Asus Striker II Extreme (if it ever comes)
A 3870X2 and 3870 in XFire on an Asus P5E3 Premium

 

[Munky]

I'm assuming this is a purely theoretical question, and nobody is actually thinking "Hmmm... should I get 3 or 4 gpu's based on last gen technology that scale with diminishing returns?" Either way, the only winner would be Jen Hsun, laughing all the way to the bank. And either setup would look like a primitive, power-sucking monstrosity compared to a next-gen gpu.

 

[AuDioFreaK39]

http://www.theinquirer.net/gb/...inqpressions-dual-asus
2 x 9800GX2 Quad-SLi + Intel Skulltrail - Only 20973 in 3DMark06?

Well, The Inquirer put out some Skulltrail + Quad-SLi benchmarks yesterday, and the results look terribly unpromising at this point. 20973 for Quad-SLi AND two quad cores. I'm sorry, but hardware like that should yield results over 25k. They also failed to reveal the CPUs they used - could've been 2.4GHz 45nm Xeons for all we know.

 

[nRollo]

Originally posted by: n7


Of course this is dependent on games that actually scale with SLI, & there are a lot more that don't than you'd believe.
All you need to do is look at how the majority of review sites use the exact same games for their reviews.

Then you have the less mainstream sites using "odd" games which don't show very positive results.

This just isn't true.

Sites like XBit use different games than the mainstream.

SLi allows the user to pick between using AFR1, AFR2, or SFR with games, and there are many profiles in the NVIDIA drivers. (there are profiles for games I've never heard of in the drivers)

Whether or not a game can be made to scale with SLi for the most part depends on how much you can make the GPU the limiting factor. This is usually done by raising the resolution, or AA.

 

[nRollo]

Originally posted by: AuDioFreaK39
http://www.theinquirer.net/gb/...inqpressions-dual-asus
2 x 9800GX2 Quad-SLi + Intel Skulltrail - Only 20973 in 3DMark06?

Well, The Inquirer put out some Skulltrail + Quad-SLi benchmarks yesterday, and the results look terribly unpromising at this point. 20973 for Quad-SLi AND two quad cores. I'm sorry, but hardware like that should yield results over 25k. They also failed to reveal the CPUs they used - could've been 2.4GHz 45nm Xeons for all we know.

People need to realize:

1. 3DMark06 at stock settings is not an accurate indicator of GPU performance, or gaming performance. (if you don't believe me, just look at any HD2900XT review and see the 2900XT beating an 8800Ultra at 3DMark06, and then getting beaten at every benchmark by the 8800Ultra)

2. 3Dmark06 at 25X16 starts to shift the limitation to the GPU by almost quadrupling the number of pixels rendered, but the 9.9% drop in performance still isn't in line with the 68% more pixels rendered. (i.e. it's still not using the SLi as well as it would if they added AA to the mix- those demo games in 3Dmark are just too old)