Crossfire vs Dual Graphics

[john.weland]

I've heard Linus say before that by adding cards in SLI or Crossfire that you don't double your memory (two 4gb cards don't become one 8gb card)  does the same apply to dual graphics setups between an APU and its discrete counter part? I have an APU with a Radeon 6550D GPU that according to the catylist control center used 4Gb of my 8GB system memory. It is connected via Dual Graphics with a Radeon HD 6670 which only has 1Gb of memory. 

 

 

[thekeemo]

I think the apu can use 4gb on  its own but the vram is limited when connected to the GPU

[Ostwind]

No it does not stack in dual graphics mode, that being said while you can set the APU to have access to 4GB of system RAM the iGPU is completely incapable of making use of it due to it's lackluster performance.

[incarnate]

due to its poor scaling, i stopped paying attention to hybrid crossfire, however, i'd say it is safe to assume that it would be limited to 1gb of vram seeing as how crossfire always uses the lowest of two mismatched values.