Random Question about Graphics Cards

[flipster]

So I need to clear this up because it's been confusing me. I know that the 27" imac has a massive resolution of 2560x1440 and i was wondering something about the graphics cards.

Does the 1GB graphics card actually help out when playing games on that resolution? Considering it is 1GB i figured that it would be plenty but at the same time i wondered what the difference between 1gb and 512mb would be because i once heard that snow leopard couldnt even use the 1gb of video ram fully. is that true

 

[TMRaven]

It's more along the lines of the graphics card not being able to use that 1gig of vram fully. The 5750 is really a mobility 5850, and its memory bandwidth is only 64gb/s, so it doesn't have the adequate bandwidth to fully use that 1gb of memory to its fullest potential. That doesn't mean the extra vram won't help in terms of providing a buffer for frame data and texture data, however. It's just that the difference between 512mb and 1gb of vram isn't as extreme as the raw memory number differential says.

 

[flipster]

So basically same computer, 512mb vs 1gb on counter strike: source and the same resolution and you would only see about a 10 fps improvement on the 1gb?

 

[TMRaven]

I don't have exact numbers to be sure, but most benchmarks show a 15-20% increase in performance from mobility 4850 to mobility 5850.

 

[flipster]

Yeah, thats what I figured haha I just wasn't sure. I have an 8,1 imac that i bought last year with the 512 mb 8800 gs and its freaking awesome. I get about 90 fps on counter strike: source with everything on the highest detail and 1920x1200 resolution.

 

[TMRaven]

Ah, ok. Yeah really no need to upgrade to the model with mobility 5850 unless you're really starved for performance. It's more of just an incremental upgrade rather than a night and day difference in performance like the vram says.