The total failure of SLI

[redmyst]

I've been struggling for weeks trying to resolve the problem of enabling Vsync in my SLI configuration (specifically for HL2). This weekend I figured out how, but more importantly, I learned that SLI is a COMPLETE AND TOTAL FAILURE in it's current offering. Read on.

I found a way to enable Vsync in SLI mode. Here's the 'trick' and it doesn't always work. If I setup a "applicaiton profile" for HL2 and make the vsync-on setting (inside the Nvidia 'performance' settings). Plus enable Vsync w/in the HL2 video options. Doing this I can get Vsync to hold for SLI mode.

That's the good news.

So here is the test:

1) I pick a point on the HL2 map which is 'tough' to render
2) Save the game
3) Collect the data using cl_showfps from the 'console' window.

Data (for same map point):
With non-SLI mode
vsync off -> 40fps
vsync on -> 32fps

With SLI enabled
vsync off -> 60fps (cool, SLI rocks just like all the reviews say)
vsync on -> 30fps (WHAT THE ....???)

So basically w/ Vsync turned ON and SLI enabled I get the EXACT SAME PERFORMANCE as I do without SLI. Nice. I'm so happy...

I tried this experiement w/ 4 of the last Nvidia Beta drivers; starting w/ 67.03 and finishing with 71.24. All the same results (+/- 3fps)

This is a HUGE flaw w/ SLI. I HOPE it is a drive issue, and not a hardware one. All I can do is pray for a fix or wait for some poor sap on Ebay to buy my two 'working' 6600 GTs.

But this entire thing begs the question -> WHY HASN'T ANYONE ELSE REPORTED ON THIS ISSUE? I see very little chatter online about this Vsync issue. The image tearing exists on both my HDTV, LCD and CRT. And it looks terrible. So why am I the only guy out here screaming about this?

Granted. The image tearing does look a lot worse on my 50" TV running at 16x9. That is a WIDE range of tearing to look at... but still?!?

 

[JBT]

I have the same problem with my solo GT with vsync enabled. Everyonce in awhile it will just drop to half of whatever the refresh rate is, its not all the time, Sometimes it will go to 45-55 but then it will drop to 37 half of 75. It even does this occationally with vsync disabled. Seems to be a driver bug or something.

 

[Mr. Lennon]

It is not a driver issue, it is the 6800 series issue. They do not support triple buffering which prevents vsync from cutting your framerates in half. Im totally pissed at myself because I just bought 2x BFG 6800 GTs and totally forgot about the vsync problem. Hl2 crashes in sli for me now:/ but I need to find a driver which will hopefully fix that. Good thing I ordered my x850 xt pe, because this junk is going strait to eBay when it gets here.

 

[Insomniak]

This is why I didn't jump into SLI off the bat. I want to see the problems people will find and what fixes/attention they get.

 

[redmyst]

How exactly can this be a h/w problem? A single card in non-SLI mode supports Vsync correctly... What am I missing? I think tripple buffering is used either way to support Vsync.

 

[Rage187]

I'll buy into it once more people pay the price of having it work OOTB.

 

[redmyst]

Hey, in defense of Nvidia - it works.... just not right.

 

[Chosonman]

Originally posted by: redmyst
But this entire thing begs the question -> WHY HASN'T ANYONE ELSE REPORTED ON THIS ISSUE? I see very little chatter online about this Vsync issue. The image tearing exists on both my HDTV, LCD and CRT. And it looks terrible. So why am I the only guy out here screaming about this?

I'm not surprised.
Here's my theory on why nobody else has reported the issue...
The smart builders avoided SLI entirely. And most of those who bought SLI just wanted to join the "Cool Tech" band wagon even though they had no idea what they were buying. So they're clueless.

And then there are advetures like yourself who tested the technology for the rest of us.

 

[beany323]

Originally posted by: redmyst
Hey, in defense of Nvidia - it works.... just not right.

rofl !! :laugh:

 

[redmyst]

Originally posted by: Chosonman

And then there are advetures like yourself who tested the technology....

I wouldn't mind so much if I had a CLUE that Nvidia was even working on this issue. But to now know and just wait to try another rotten Beta driver release... really stinks. This makes things in the wireless industry look professional

BTW: I've tried 6 different drivers w/ these 6600 cards and only ONE of them didn't crash my PC on installation!! But hey, it's Beta...

.. and on I gripe.

 

[EarthwormJim]

Originally posted by: Zeppelin2282
It is not a driver issue, it is the 6800 series issue. They do not support triple buffering which prevents vsync from cutting your framerates in half. Im totally pissed at myself because I just bought 2x BFG 6800 GTs and totally forgot about the vsync problem. Hl2 crashes in sli for me now:/ but I need to find a driver which will hopefully fix that. Good thing I ordered my x850 xt pe, because this junk is going strait to eBay when it gets here.

I never heard of this issue before. Anyways triple buffering is for Opengl, so it wouldn't matter for Half Life 2.

 

[ronnn]

What I don't understand about sli, is that I have been hearing about it for months. Still except for a few reviews, have read nothing from people who actually own a 6800ultra sli set up. Would be nice to hear if consumers felt it was worth the price.

 

[Viper96720]

Majority of gamers play with vsync off for max frame rates. Probably why problem isn't well known

 

[zakee00]

Originally posted by: Zeppelin2282
It is not a driver issue, it is the 6800 series issue. They do not support triple buffering which prevents vsync from cutting your framerates in half. Im totally pissed at myself because I just bought 2x BFG 6800 GTs and totally forgot about the vsync problem. Hl2 crashes in sli for me now:/ but I need to find a driver which will hopefully fix that. Good thing I ordered my x850 xt pe, because this junk is going strait to eBay when it gets here.

^^^^

 

[TantrumusMaximus]

What's the big deal? I NEVER use Vsync so I could care less also I'm sure this isn't some big showstopper for SLI. You guys are ranting about something just like how people rant when a new game comes out that needs patching. Anything NEW technology wise you take a risk when you buy it. First adopters ALWAYS end up compromising. nVidia will fix this if it is a BIG PROBLEM I'm sure.

 

[Jeff7181]

Thanks all of you for doing a public beta test for the rest of us.

People kept asking me last fall about the nForce4 and PCI-Express and SLI and I kept telling them stick with nForce3 and your AGP card for now and wait for any bugs to be worked out of the nForce4 chipset and SLI because there's bound to be issues.

BTW... that triple buffering thing sounds like something that may be able to be fixed in a driver release. Cause I can use triple buffering with my 6800GT AGP. So it's not an inherent problem with the 6800 GPU architecture...

 

[Jeff7181]

Originally posted by: redmyst

Originally posted by: Chosonman

And then there are advetures like yourself who tested the technology....

I wouldn't mind so much if I had a CLUE that Nvidia was even working on this issue. But to now know and just wait to try another rotten Beta driver release... really stinks. This makes things in the wireless industry look professional

BTW: I've tried 6 different drivers w/ these 6600 cards and only ONE of them didn't crash my PC on installation!! But hey, it's Beta...

.. and on I gripe.

Come on nVidia software guys... you might lose a customer here. Stop what you're doing and come answer this guy.

Actually... just put a webcam over your shoulder so while you're working during the day we can all check on you and make sure you're actually working.

And while you're at it... why don't you make your beta drivers more stable... damn... those incomplete, untested, pre-release drivers suck!

:roll:

 

[HighCalibreHooch]

I don't normally chip in on threads that flame companies, but I have to agree here on principle. As soon as I heard about 'SLI' for nVidia I thought to myself: 'gimmick!'

For me the math just doesn't make sense.

2 6600GTs + beefy PSU > 1 6800 GT

As for the vsync bug...........

 

[302efi]

Please read my sig...The should answer all your questions

 

[ribbon13]

True SLi is only supported by dual cpu systems at the moment any. only nForce Pro 2200+2050 has enough lanes for two x16 PCIe slots. Has anyone ran a 6800 Ultra SLi steup on a Tyan Thunder K8WE?

 

[Avalon]

Originally posted by: ribbon13
True SLi is only supported by dual cpu systems at the moment any. only nForce Pro 2200+2050 has enough lanes for two x16 PCIe slots. Has anyone ran a 6800 Ultra SLi steup on a Tyan Thunder K8WE?

That would be sweet.

 

[Regs]

Originally posted by: ribbon13
True SLi is only supported by dual cpu systems at the moment any. only nForce Pro 2200+2050 has enough lanes for two x16 PCIe slots. Has anyone ran a 6800 Ultra SLi steup on a Tyan Thunder K8WE?

The bandwidth is not needed and likely won't be for years to come. Other than that, you'd see no difference.

 

[ribbon13]

Not true. I imagine a x16 PCIe RAID card with enough solid state drives could use it all, and would be useful in servers. Too bad none exist in the market. Yet. Heh.

As for graphics, the new Wildcats will push 8x slots to thier limits. But for mainstream, but will be a few years for that bandwidth to be actually useful. I'll give you that. That is the very reason why I want a K8WE so bad. I wonder how many years it will be before I actually NEED to upgrade. heh.

 

[bersl2]

You know, maybe the real reason why nvidia won't open up their drivers to us open source people is because they'd be too embarassed when everybody discovers that their drivers' code looks like crap.

 

[ribbon13]

My god.... That just makes tooo much sense.