Crossfire/SLI programming related question

[frobot]

I am currently looking for a new computer and I found one I really like - http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1125279&sku=I455-92700
It comes with 2x Radeon HD 6850 in Crossfire.

I am into graphics programming and don't really play any games.
Will having dual GPU's have an automatic effect, or do you have to programatically take advantage of more than one GPU?
And I have the same question about having multiple CPU cores. It has 4 cores, but when does a computer utilize these cores? And from a programmer's standpoint, how do you take advantage of them?
I have been programming on a 10+ year old pc for many years now, so I'm lost when it comes to the more modern technology.

Also feel free to give any advice on the computer I have selected in general. I'm still not sure what best suits me.

 

[bloc97]

Graphics Programming? No High-Detail modelling?

It depends.

Two Crossfire cards won't really benefit from "Programming" except if you need to do some modelling or textures design.
For the CPU, even an Single Core would suffice for simple graphics programming.

Also, can you define with more details what you mean by "graphics programming".

Hope it helps!

 

[bloc97]

You should also take an HD 7970 instead of two 6850's. It is faster and uses less power.

Why do you buy from tigerdirect? Go to ibuypower.com and build your own computer. You can add better features or remove useless ones.

 

[frobot]

I guess you could say I do game graphics.
Natural things like water simulation, terrain, atmospheric scattering, ray tracing etc. are what I'm really into.
I could certainly benefit from multiple cores though.
I'm actually looking around on ibuypower right now. Haven't found something like this computer but you're right, I'm sure I can build something.

 

[bloc97]

If it is that kind of graphics programming, then yes you can get a good Graphic Card with a high GPGPU Performance (for water sim and ray tracing), like the newer 7xxx cards.
I personally have a HD 7770, and it works pretty well for gaming at 1080p.

You could also benefit from an HyperThreaded CPU. (i7 2500k)

 

[frobot]

Ok I'm liking this ibuypower custom build thing.
I had tried digitalstorm and it was all just too expensive and overkill for me.

So scratch the multiple GPU thing off, if I'm personally selecting what is in the computer I'd rather just have a high end single GPU.
Still wondering about multiple cores, but I'm sure a little research will turn up some interesting things about that.

Also if anyone knows any other pc building sites please do share.

 

[bloc97]

There is also Cyberpower.com

 

[frobot]

Do sites like these actually assemble the computer? Seems like a dumb question, but I just came across an option that asks if I want "professional wiring" done...

 

[fb39ca4]

I'm confused. Do you want to write programs to take advantage of the two GPUs or want to use the GPUs to accelerate normal code?

 

[frobot]

To be more specific if I am writing code in DirectX and HLSL, will having two GPU's increase my performance automatically? or will I have to learn how to take advantage of it through code.

 

[bloc97]

I never bought a computer from their sites but if they ask you an option of "professional wiring", I think they may build the computer for you...

But I thought for a long time that they didn't assemble the PC for you.
Try to read the FAQ's or telephone them.

 

[bloc97]

To be more specific if I am writing code in DirectX and HLSL, will having two GPU's increase my performance automatically? or will I have to learn how to take advantage of it through code.

It depends, if you don't optimize your code, the driver can try to do that for you, but without too much acceleration.
If you optimize your code, it should "practically" double the performance.

Also, which API? DX9, DX10 or DX11?
Do you write in OpenGL and GLSL too?

 

[frobot]

I currently use dx9 because like I said I have 10+ year old hardware =(
Should be switching to dx11 though as soon as I get a new machine.
I haven't learned any OpenGL and probably won't for now.

 

[bloc97]

10+ Year old Hardware? That sounds more DX7 or DX6 to me...

For DirectX 9, you need to completely code with Dual-Cards in mind, but for DirectX11, as I said earlier, the driver can do that partially for you, but without much acceleration.