Did SLI and Crossfire fail because they had to work with two cards?

Quartz · 22 Sep 2020 at 11:09

Looking back, it seems to me that the critical flaw with both SLI and Crossfire was that they had to work with two cards when it should have been a minimum of three. With two cards you can get the dreaded micro-stutter, but with three, you can have two (or more) doing the graphical work - alternate frame rendering - feeding to the third which acts as a sync card and outputs a micro-stutter free image to the display. Unfortunately neither Nvidia nor AMD went this route. As a bonus, since the games only interact with the sync card, this would be invisible to the game so profiles would not be needed.

How say you?

pugheaven · 22 Sep 2020 at 11:16

Tri Fire was the sweet spot imho with AMD cards, I had a 290x with a 295x2 for a long time (infact until this year from day one release and replaced with my current 5700XT) and it was sweet as a nut.

Was it perfect, no, but when it worked it worked really well and say running BF3/BF4 etc was sublime. Duel cards worked, it was just development... however, I did mention on another trhead that AMD could dive in here and if they'd also not walked away from Xfire, there is now a niche they could've filled now nVidia has officially walked away from driver support. It's a shame, I loved it but it was less than 1% of the market and just not worth it... such a shamne though as I loved running multiple cards or outright processing power. Such a shame :-(

It'll never come back now unless someione makes a big effort on it, and that boat has sailed... gutting really as it gave upgrade paths when it worked. I'm running 2 x AMD 570s in my 2nd rig and it runs sweet as. However only running one 5700XT as NAVI doesn't support it and tbh if I could I'd have already added another 5700XT but it'll sit there doing nothing.

Quartz · 22 Sep 2020 at 16:43

But with three cards you still got micro-stutter under the current schema, just less of it. In what I'm proposing, one of the three cards acts purely as a synchronisation and output card.

stooeh · 22 Sep 2020 at 16:52

I think the reason it failed is because over time modern engines started to do more work that relied on previous frame data which would have been on the other card. Ultimately making it more effort on the developers for a niche market. I also was not a big fan of the extra frame delay that you see in AFR which meant while 60 fps with 2 cards looked fine it felt like 30 fps mouse input lag.

Chrisc · 22 Sep 2020 at 16:54

I ran dual 6850's on my return back to PC gaming around 2010 a long with a new FX8120. When Xfire worked it was great, when it didnt it made you question why you didnt just buy one really good card

Gerard · 22 Sep 2020 at 16:56

I'm near sure there was a single card at one point with 3 gpu's on it, maybe around 2011 or thereabouts. Might have been a tech demo or something maybe.

Unisol Magic · 22 Sep 2020 at 17:36

It’s a depressing situation for us SLI owners

£2500 spent on 2 Titan Xp’s back in 2017 which would now likely still stack up against a 3080

Having said that I’m still enjoying playing SLI enabled games eg Prey

gpuerrilla · 22 Sep 2020 at 18:08

pugheaven said:
Tri Fire was the sweet spot imho with AMD cards, I had a 290x with a 295x2 for a long time (infact until this year from day one release and replaced with my current 5700XT) and it was sweet as a nut.

Was it perfect, no, but when it worked it worked really well and say running BF3/BF4 etc was sublime. Duel cards worked, it was just development... however, I did mention on another trhead that AMD could dive in here and if they'd also not walked away from Xfire, there is now a niche they could've filled now nVidia has officially walked away from driver support. It's a shame, I loved it but it was less than 1% of the market and just not worth it... such a shamne though as I loved running multiple cards or outright processing power. Such a shame

It'll never come back now unless someione makes a big effort on it, and that boat has sailed... gutting really as it gave upgrade paths when it worked. I'm running 2 x AMD 570s in my 2nd rig and it runs sweet as. However only running one 5700XT as NAVI doesn't support it and tbh if I could I'd have already added another 5700XT but it'll sit there doing nothing.

I was a massive fan of it. I tried it on 2 nvidia cards early days, was ok - then I remember using two 7770's as I must have been skint yet picked a second up some months later, this was a bit more temperamental, then I got the 7990 which ran well until it failed and got RMA. I liked the idea of later down the line adding more of the same for better performance. It could boon again if something triggers it, but would be handier if the games just found a way of noticing the resources available and it sussed it out once detected.

Never tried tri-fire that sounds good (with what you explained with microstutter).

pugheaven · 22 Sep 2020 at 18:38

Th0nt said:
I was a massive fan of it. I tried it on 2 nvidia cards early days, was ok - then I remember using two 7770's as I must have been skint yet picked a second up some months later, this was a bit more temperamental, then I got the 7990 which ran well until it failed and got RMA. I liked the idea of later down the line adding more of the same for better performance. It could boon again if something triggers it, but would be handier if the games just found a way of noticing the resources available and it sussed it out once detected.

Never tried tri-fire that sounds good (with what you explained with microstutter).

I actually had quadfire mate, I'd bought two water cooled 295x2's... the power in those was insane... BUT games just wouldn't run right hence I sold one a few months later and ran tri instead and that was like butter really was... WHEN it worked lol...BF3/BF4 were amazing in trifire... I was running 3x1080P monitors maxed with them, was amazing, and those days are gone now because you can't get a card that'll run 3x4k monitors that I have now... I miss my multi monitor gaming but you need power and no single card has enough... unless I ran 1080P again on these... suppose the 3000 series possibly would nicely.

gpuerrilla · 22 Sep 2020 at 18:42

pugheaven said:
I actually had quadfire mate, I'd bought two water cooled 295x2's... the power in those was insane...

Wow that would have been sweet. I got a 290X after the 7990, I later modded an AIO to it and it was quiet with low temps. Some years passed and I checked out the then top card RX 580 lol couldnt believe it wasnt really an upgrade so I passed that gen.

Jacky60 · 22 Sep 2020 at 19:03

pugheaven said:
I actually had quadfire mate, I'd bought two water cooled 295x2's... the power in those was insane... BUT games just wouldn't run right hence I sold one a few months later and ran tri instead and that was like butter really was... WHEN it worked lol...BF3/BF4 were amazing in trifire... I was running 3x1080P monitors maxed with them, was amazing, and those days are gone now because you can't get a card that'll run 3x4k monitors that I have now... I miss my multi monitor gaming but you need power and no single card has enough... unless I ran 1080P again on these... suppose the 3000 series possibly would nicely.

Had Quadfire 6990s and 295x2s and trifire 5970/5870. Still rocking 1080ti SLI and in the games I play it still works well. Always loved multi-gpu especially with fastest available cards because then it's unbeatable in any game. Shame the support has gone tbh.

pugheaven · 22 Sep 2020 at 19:09

Jacky60 said:
Had Quadfire 6990s and 295x2s and trifire 5970/5870. Still rocking 1080ti SLI and in the games I play it still works well. Always loved multi-gpu especially with fastest available cards because then it's unbeatable in any game. Shame the support has gone tbh.

Yep I had quadfire 6990's as well, that was a beastly system to... I went from the 6990's to the 295x2's actually myself so we followed a similar path. I only changed this year to a 5700XT as was about time I upgraded system etc... yep, would love AMD to sneakily role out another dual card, would be awesome, just for the hell of it hahaha but somehow make it work... but lets be honest, it's not going to happen. good memories though have to admit, just seeing the power consumption and your PC absolute loaded with tech... my PC looks properly empty now... TBH if Big Navi is cool I might just buy two of them and fold 24/7 on one of them and use the otehr for gaming, I think I could still do that no problem? At least I'd have a nice looking water loop etc, would look brill with two cards again!

gpuerrilla · 22 Sep 2020 at 19:13

I still buy mobo's that can run it.. just in case

Rroff · 22 Sep 2020 at 19:24

Quartz said:
Looking back, it seems to me that the critical flaw with both SLI and Crossfire was that they had to work with two cards when it should have been a minimum of three. With two cards you can get the dreaded micro-stutter, but with three, you can have two (or more) doing the graphical work - alternate frame rendering - feeding to the third which acts as a sync card and outputs a micro-stutter free image to the display. Unfortunately neither Nvidia nor AMD went this route. As a bonus, since the games only interact with the sync card, this would be invisible to the game so profiles would not be needed.

How say you?

You still have the same issue in that if card A is working on a frame ahead of card B but card A needs the data from card B to process some effects then card A stalls waiting on card B then if card B finishes its work it can't start until it has the results of card A and so on. You could employ some mechanism of dividing up the scene between cards but the scaling of that is always limited without carnal knowledge of the scene (hence why developers implementing explicit multi-adapter is pretty much always superior).

Seen some interesting information, not sure if it is something that is just an experiment out of curiosity or what, that one approach being looked at currently is some form of having MCM hardware that actually presents as a dozen virtual GPUs with each being divided out bits of the scene with the ability to dynamically allocate the resources each one has on the fly depending on load.

Quartz · 22 Sep 2020 at 19:36

Rroff said:
Seen some interesting information, not sure if it is something that is just an experiment out of curiosity or what, that one approach being looked at currently is some form of having MCM hardware that actually presents as a dozen virtual GPUs with each being divided out bits of the scene with the ability to dynamically allocate the resources each one has on the fly depending on load.

Having each GPU render part of the image was one of the original ways that SLI worked. It quickly fell out of favour IIRC.

Rroff · 22 Sep 2020 at 19:37

Quartz said:
Having each GPU render part of the image was one of the original ways that SLI worked. It quickly fell out of favour IIRC.

Some games still used SFR - you could force it on as well - there were even several variants of it. Problem was actually dividing out the scene somewhat equally for the GPUs.

Quartz · 22 Sep 2020 at 19:39

Rroff said:
Some games still used SFR - you could force it on as well - there were even several variants of it. Problem was actually dividing out the scene somewhat equally for the GPUs.

Ah yes, SFR. I didn't know it was still used.

Unisol Magic · 22 Sep 2020 at 20:12

Th0nt said:
I still buy mobo's that can run it.. just in case

Me too

subbytna · 22 Sep 2020 at 20:19

IMO, it "failed" as two lesser priced cards would usually smash the higher tier card and lose Nvidia money as nobody would get the expensive card when two other cards were cheaper.

Scania · 22 Sep 2020 at 20:23

I've got a 4K screen and a 1080ti, recently I bought a second 1080ti to use in SLI with my Zotac Amp Extreme in SLI, schoolboy error, I bough an MSI lightening with 3 slot triple fan configuration, temps were absurd.

I've moved it on but, especially given current pricing, I'm after a 2 slot blower card in replacement.

The performance boost - in the games I play - was generally excellent and I can't say I noticed any micro stutter.

More than happy to get that second 2 slot card, in the long term, SLI is dead. RIP, it could and should have delivered so much more....