Cross fire question

[OnionRings]

Can you crossfire any GPU or do they have to match? I thought once apon a time that you could mix GPUs. 

[COUPER MILLAR]

DX 12 technically supports mixing, however best performance will always come with matching. 

[DocSwag]

They have to match, somewhat. You can't crossfire a fury x with, say, a 480 but I know that you can crossfire, say, a 390 with a 290 or a 290 with a 390x. I'm not too sure about others though.

[OnionRings]

Just now, DocSwag said:

They have to match, somewhat. You can't crossfire a fury x with, say, a 480 but I know that you can crossfire, say, a 390 with a 290 or a 290 with a 390x. I'm not too sure about others though.

 

What about a 480 with a 470?

[DocSwag]

Just now, OnionRings said:

What about a 480 with a 470?

I think so. There's a lot of videos and posts online of people getting it to work. Though why not just 480 with 480 instead?

[OnionRings]

Just now, DocSwag said:

I think so. There's a lot of videos and posts online of people getting it to work. Though why not just 480 with 480 instead?

Just curiosity, If I were to crossfire I probably would match. What about different Vram amounts? Like a 480 8GB with a 480 4GB?

[Damascus]

1 minute ago, OnionRings said:

Just curiosity, If I were to crossfire I probably would match. What about different Vram amounts? Like a 480 8GB with a 480 4GB?

You'd get  2GB usable per card

[OnionRings]

Just now, Damascus said:

You'd get  2GB usable per card

It takes the lower amount and makes that what you use? If I cross fired 2 8GB cards would I have 8GB usable?

[Damascus]

Just now, OnionRings said:

It takes the lower amount and makes that what you use? If I cross fired 2 8GB cards would I have 8GB usable?

The way crossfire and SLI work is like this:

 

2 RX 480 8GB

When you crossfire they share that VRAM 2 ways so

8/2 = 4GB per card.

 

If it was an RX 480 8GB + 470 4GB

The VRAM is limited by the lowest common denominator so

4/2 = 2GB per card

 

The extra 4GB on the RX 480 is locked away and unusable.

[DocSwag]

6 minutes ago, OnionRings said:

Just curiosity, If I were to crossfire I probably would match. What about different Vram amounts? Like a 480 8GB with a 480 4GB?

It would work but I think you'd only get 4gb essentially. 4gb on one card would go unused.

[OnionRings]

Just now, Damascus said:

The way crossfire and SLI work is like this:

 

2 RX 480 8GB

When you crossfire they share that VRAM 2 ways so

8/2 = 4GB per card.

 

If it was an RX 480 8GB + 470 4GB

The VRAM is limited by the lowest common denominator so

4/2 = 2GB per card

 

The extra 4GB on the RX 480 is locked away and unusable.

 

That makes sense.

[Princess Luna]

6 minutes ago, Damascus said:

The way crossfire and SLI work is like this:

 

2 RX 480 8GB

When you crossfire they share that VRAM 2 ways so

8/2 = 4GB per card.

 

If it was an RX 480 8GB + 470 4GB

The VRAM is limited by the lowest common denominator so

4/2 = 2GB per card

 

The extra 4GB on the RX 480 is locked away and unusable.

You're explaining it so weird, just say that in order to crossfire/sli to work both cards need to have access to the same data therefore they fill up their VRAM equally resulting that VRAM doesn't stack [:

 

[Damascus]

Just now, Princess Cadence said:

You're explaining it so weird, just say that in order to crossfire/sli to work both cards need to have access to the same data therefore they fill up their VRAM equally resulting that VRAM doesn't stack [:

 

Eh, I guess this is just how I think of  it.  I tried explaining to a guy who was convinced his 3*2GB GTX 660's = 6GB usable RAM for almost 2 hours and now I just use the most simple and obvious way possible to explain the math

[Princess Luna]

1 minute ago, Damascus said:

Eh, I guess this is just how I think of  it.  I tried explaining to a guy who was convinced his 3*2GB GTX 660's = 6GB usable RAM for almost 2 hours and now I just use the most simple and obvious way possible to explain the math

Not like that it even matters, VRAM isn't as important as it seems, just have 4gbs and you're set for today, more than ten years and we just went from 1gb ideal to avoid 2gb... people concern themselves too much about VRAM fearing it'll bottleneck them and yes if you have insufficient VRAM then the game is unplayable but no game won't run on 4gb nowadays anyways... still long before it's not enough.

 

The ONLY time I saw a game use more than 10gb of VRAM was CoD IW and that's only because it stores the video cutscenes there when you have enough free space lol not exactly optimized if you ask me but if your card is 4gb the game runs normal just stores it where it should be stored, on the drive.

[Damascus]

1 minute ago, Princess Cadence said:

-snip-

Totally agree.  If the 4GB model of VEGA is well clocked and cheap enough to be value I'd go for it.  Though I want to go high res in the future so  

[Princess Luna]

Just now, Damascus said:

Totally agree.  If the 4GB model of VEGA is well clocked and cheap enough to be value I'd go for it.  Though I want to go high res in the future so  

Even higher resolution isn't that much of a problem if you don't do some crazy texture modding, my main point is, going with a rx470 8gb for instance is silly because by the time you will actually need to use 5gb~8gb VRAM to play your game, the card will be too slow to run it acceptably any ways

[Princess Luna]

By the way, OP; how are you going to crossfire with a H110m-A?

[Damascus]

2 minutes ago, Princess Cadence said:

Even higher resolution isn't that much of a problem if you don't do some crazy texture modding, my main point is, going with a rx470 8gb for instance is silly because by the time you will actually need to use 5gb~8gb VRAM to play your game, the card will be too slow to run it acceptably any ways

Yeah, that was the debate for 960m 4GB vs 970m 3gb.  It's obvious to me (now) but to the uneducated among us it's "herpa derp, better go with more RAM!"

 

My best friend does that.  I'm like, OK what GPU are we getting? Show him 1050 ti and RX 470.  HOW MUCH RAM?!?

Chooses RX 480 strix because its pretty....

[OnionRings]

5 hours ago, Princess Cadence said:

By the way, OP; how are you going to crossfire with a H110m-A?

Magic.

 

Seriously though I'm not, but I was planning on upgrading to Ryzen 5, getting a B350 board with 2 slots, and maybe down the line if crossfire support for games gets better, getting a 2nd 480 instead of dropping 500$ on a 1070.