I had a 4870x2 back in the day... I actually bought 2 of them but one was DOA and Visiontek replaced both of them under warranty with a pair of 6870 cards. I still have the 6870 cards.

After that I went to a 7970 and then a pair of 7970s. Once AMD fixed the frame timing issue they were even better than before.

As for running xfire with 2 different cards, it will always run the higher end card as if it were the lower end card.

If you run a game that wants more than 512MB video ram, then then 4830 is going to choke.... watch out for higher resolutions and higher detail settings in some games.

I thought that my primary card (1GB 4890) would downclock to 4830 performance but keep the 1GB of VRAM in use. I guess I'll find out if performance collapses when I go over 512MB of video memory,

I think a 7970 xfire set up would be surprisingly usable today (other than, you know, the heat and noise and power consumption and chewing up PCI-E bandwidth...)

Almoststew1990 wrote on 2020-08-11, 19:19:

I thought that my primary card (1GB 4890) would downclock to 4830 performance but keep the 1GB of VRAM in use. I guess I'll find out if performance collapses when I go over 512MB of video memory,

I think a 7970 xfire set up would be surprisingly usable today (other than, you know, the heat and noise and power consumption and chewing up PCI-E bandwidth...)

The cards in xfire mirror what is in memory, so I am pretty sure you will only get 512MB usable.

2x7970 is about the same speed as a single R9-390 with the 390 being much better in a lot of things due to 8GB of RAM plus other improvements. That was the card I had after the 7970s.

Unfortunately, I'm not knowledgeable on Crossfire or SLI. One of the reasons I'm not knowledgeable, is because it is never a worthwhile endeavor, especially not in retro builds. A newer, more powerful card always gives better performance at lower power consumption.

But I remember the 4800 series fondly. They were notoriously hot, often sold with noisy fans, and more prone to failure than the average card, somehow. A friend of mine whom I recommended one of those, back when they were the top performers, still jokes how that is the only bad hardware advice he had gotten from me during our more than two decades of acquaintance. 😜

I'm always amazed when I see a 48x0 series card with no VRM cooling. Some 4850 cards had a GPU idle temp around 85C and load at 110C. Of course NVidia was doing the same thing to their 8800GT cards. Price war shenanigans I suppose.

But it will crossfire at the lower card's speed?

Yes.

I wonder if crossfire 4830s (with 1GB of video memory, which it never existed) will be slower than a single 4890?

Yes.

Any news on which drivers would work best?

In general, latest driver is the best.

Any games that love crossfire?

Techpowerup has good collection of games tests to consider. Although listed frame rate doesn't mean sh*t due to AFR shenanigans.

General recommendation:
Never allow GPUs in Crossfire to be fully loaded, that would only lead to random frametime spikes. Use Vsyns and/or frame rate limiter to tweak workload. 70-80% load on both GPUs should allow more or less smooth experience. It takes some effort and sacrifices to tweak Crossfire setup of that era. If particular game can't work at stable 60 fps, you should roll back to 40 or even 30 fps cap or lower settings.

I can add some thoughts about CF on Radeon HD 4800 series.

1. 512 + 1024MB card never worked for me. Same memory size is ok. You can even run HD 4830 512MB + HD 4870 512MB and get some performance gain.

2. Latest drivers are crap, for me Catalyst 12.1 works reasonably well, using Win7 64 OS, that is. Not sure about XP or other OS.

3. Most of period correct games (released 2009 or earlier) should support CF well. Later ones might too, but it is a hit or miss.

4. Most of the time there will be some amount of micro stuttering and increased input lag.

Does anyone know whether I will get improved performance if I use two xfire bridges between the two cards?

Almoststew1990 wrote on 2020-08-12, 10:54:

Does anyone know whether I will get improved performance if I use two xfire bridges between the two cards?

Nope.

Catalyst Legacy 13.1 is a no go? I usually run that with DirectX 10 cards. For Win7 and later at least.

If you want to play some older games you actually need to stick to Catalyst 7.11 or older which Radeon 4xxx can't even use. KOTOR 1/2 and Star Wars Republic Commando are examples. They overhauled the OpenGL to the detriment of various old games and also broke something with Direct3D 8.

With XP I've also seen some weird stuttering with drivers after about 10.6. But that may be limited to HD 2000 cards.

The Catalyst 12.x series was a disaster for HD 2000-4000. Some of those releases actually had broken 3D rendering. Problems with their driver development team during those days I guess. They pulled things together once they announced the cards were going legacy.

I have a X1950XTX Crossfire Edition that I keep thinking about trying to buddy up with a Master card someday. I have never SLIed or Crossfired anything DirectX9 or newer.

I have a X1950XTX Crossfire Edition that I keep thinking about trying to buddy up with a Master card someday

Hardware Crossfire is actually pretty nice since you can use tiling as rendering method, but support is limited.

The Serpent Rider wrote on 2020-08-12, 18:44:

Hardware Crossfire is actually pretty nice since you can use tiling as rendering method, but support is limited.

Yeah the tiling mode is very appealing.

swaaye wrote on 2020-08-12, 18:28:

The Catalyst 12.x series was a disaster for HD 2000-4000. Some of those releases actually had broken 3D rendering. Problems with their driver development team during those days I guess. They pulled things together once they announced the cards were going legacy.

Interesting, for me it was the opposite. I tried the legacy drivers (14.something and perhaps earlier too) and it was a mess, especially when running multi GPU. I had 2x HD 3870 at my test bench at the time and for instance Crysis scaled poorly and with tons of micro stuttering. I went back a few versions and with 12.1 it was much better. Also with 3-way CF the scaling was nearly perfect and no stuttering at all. Later with single HD 4870 I remember F1 2010 was slower with legacy Catalyst compared to 12.1 and Shadow Warrior (the 2013 remake) had some graphic glitches... also fixed with 12.1.

I still have some data from the HD 3870 CF run:

havli wrote on 2020-08-13, 05:50:

Interesting, for me it was the opposite. I tried the legacy drivers (14.something and perhaps earlier too) and it was a mess, especially when running multi GPU. I had 2x HD 3870 at my test bench at the time and for instance Crysis scaled poorly and with tons of micro stuttering. I went back a few versions and with 12.1 it was much better. Also with 3-way CF the scaling was nearly perfect and no stuttering at all. Later with single HD 4870 I remember F1 2010 was slower with legacy Catalyst compared to 12.1 and Shadow Warrior (the 2013 remake) had some graphic glitches... also fixed with 12.1.

I will have to give 12.1 a try sometime. I have had good luck with Legacy 13.1 on Win7/8/10 though. With WinXP I tend to use 7.11.

I think if you were to try some other 12.x releases on a 4xxx card you would discover rendering corruption problems though. 11.10-11.12 were the Rage debacle with confusing betas/hotfixes thrown in to make the game work. Then 12.1 must have been a panacea. Until 12.4 or something when rendering problems appeared on 4xxx cards. And then AMD announced they were reworking their Catalyst program because it was a mess. 😀
https://www.anandtech.com/show/5880/amd-disco … talyst-126-beta