MP 6,1 Silly question about D300/D500/D700 video cards

[sheapuppy]

Silly question about the MP 6,1. I noticed that there are two matching boards typically with an AMD D300/D500/D700 GPU. Does that mean that each machine has either 4GB, 6GB, or 12GB total for the GPU RAM?

 

[avro707]

Does that mean that each machine has either 4GB, 6GB, or 12GB total for the GPU RAM?

If I understand the question then yes, D700 machines are 2x 6GB, each card has 6GB on it, but they are A and B cards, not identical to each other. If it were possible to have two cards each with the storage on it would be brilliant.

 

[sheapuppy]

If I understand the question then yes, D700 machines are 2x 6GB, each card has 6GB on it, but they are A and B cards, not identical to each other. If it were possible to have two cards each with the storage on it would be brilliant.

Yup I understand that they are A/B cards, so the total GPU RAM combo for a 6,1 is either 4GB, 6GB, or 12GB, right?

 

[avro707]

Yes, but I don’t know if the apps see them as 12gb or as 2x 6GB.

 

[DeltaMac]

I could be wrong on this, but aren't there two graphics cards to provide more ports? But the output of the cards cannot be combined, so only 2GB, 3GB, or 6GB max RAM is available on any one port.

 

[jmcube]

The cards are separate. I found it difficult/impossible to use both for computation. I generally ended up only using one for computation.

 

[h9826790]

I could be wrong on this, but aren't there two graphics cards to provide more ports? But the output of the cards cannot be combined, so only 2GB, 3GB, or 6GB max RAM is available on any one port.

Only GPU B can display. As you can see from the block diagram, there is no link between the ports and GPU A. So, GPU A isn't there for more ports, but for more power to compute only.

Each card has their own VRAM, cannot be shared use. If the compute software can combine the VRAM pool by itself, then yes, you may get 12GB VRAM in total (for D700 only). But for 3D / display, only GPU B's VRAM can do the job.

Silly question about the MP 6,1. I noticed that there are two matching boards typically with an AMD D300/D500/D700 GPU. Does that mean that each machine has either 4GB, 6GB, or 12GB total for the GPU RAM?

There is no requirement to use symmetrical GPU. e.g. If you only need a D700 for 3D stuff, then you can buy a D700 (GPU B card) to upgrade a D300 nMP by yourself. 8GB VRAM in total, not 4, 6, or 12, but the 6,1 can still function normally.

 

[h9826790]

The cards are separate. I found it difficult/impossible to use both for computation. I generally ended up only using one for computation.

For something like FCP / Luxrender, the software should able to use all available GPU automatically.

But for any compute job that related to the stuff displaying on the screen (e.g. real time 3D computing), then only the GPU which connecting to the monitor can do the job. There is no Crossfire in macOS.

 

[mattspace]

Yup I understand that they are A/B cards, so the total GPU RAM combo for a 6,1 is either 4GB, 6GB, or 12GB, right?

As is being said above - your effective VRAM for any "you need a GPU with this much VRAM" figures, is the total from ONE card only.

So a D700 machine is a 6GB GPU machine in every meaningful way, except that it also has a 6GB compute accelerator, which some apps can use.

 

[zapmymac]

For something like FCP / Luxrender, the software should able to use all available GPU automatically.

But for any compute job that related to the stuff displaying on the screen (e.g. real time 3D computing), then only the GPU which connecting to the monitor can do the job. There is no Crossfire in macOS.

Now there isn’t a name I’ve heard in ages: Crossfire.

 

[sheapuppy]

View attachment 2368475 Only GPU B can display. As you can see from the block diagram, there is no link between the ports and GPU A. So, GPU A isn't there for more ports, but for more power to compute only.

Each card has their own VRAM, cannot be shared use. If the compute software can combine the VRAM pool by itself, then yes, you may get 12GB VRAM in total (for D700 only). But for 3D / display, only GPU B's VRAM can do the job.


There is no requirement to use symmetrical GPU. e.g. If you only need a D700 for 3D stuff, then you can buy a D700 (GPU B card) to upgrade a D300 nMP by yourself. 8GB VRAM in total, not 4, 6, or 12, but the 6,1 can still function normally.

Thanks! I was going to ask WHY any Mac OS only "sees" 2 GB, 3GB, or 6GB of GPU RAM, and you've answered my question. That said, I like the 8GB option you proposed as I do FCP from time to time and 3D rendering. It may be difficult to find a standalone D700 card B, but I'll keep my eyes open on the bayer.