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Whoo I'm back and finally updating this thing.
"CrossFire" is the brand name of ATi's multi-GPU solution, it's competitor, SLI a technology developed by rival nVidia.
Before branded as a commercial multi-GPU solution, CrossFire was known as AMR(ATi Multi-Rendering), a solution primarily used by Evans and Sutherland for commercial flight simulators created in early 2002.
After a after a major overhaul of architecture in mid-2005, "AMR" was then branded as ATi CrossFire and released on September 27, 2005 as a solution to compete against SLI.
There are currently 2 forms of ATi's Crossfire platform; one which requires internal bridges, and the lower-end software method.
The last graphics card to use this method was the X1900XTX. A master card and a large cord connecting the two cards externally was required.
Internally-Bridged Crossfire "Native CrossFire" - Now called CrossFireX
Allows the use of internal bridging with a ribbon-cable similar to SLI's method of connecting GPUs together.
There are 2 bridge connection slots on each card and there is no predefined limit as to how many GPUs can be CrossFired together, the current limit is 4 GPUs, which meas 2 dual-gpu cards like the 5970/4870X2, or 4 single-cpu cards. No master card is required, No more dongle. Your only concern is having a bridge for 2 cards, or 2 for triple, or 3 for quad cards. They come with graphics cards or motherboards, if you're interested in CrossFire make sure to keep an eye out for that or you'll have to buy separately.
Software Crossfire
Who needs bridges or dongles when you have a PCIe bus that has plenty of bandwidth?
Software Crossfire is generally intended for lower end GPUs, integrated and dedicated cards that do not require any more bandwidth then what the PCIe interface can provide for them to communicate.
To do: Get accurate(unbiased/up-to-date) benchmarks.
EDIT: No you.
SuperTiling: The image is distributed to the rendering GPUs with a checkerboard pattern to evenly distribute the workload.(default if supported)
Scissor: Similar to SLI's default rendering method, Scissor horizontally divides the rendering view into one chunk per GPU/
Scissor(dynamic): Dynamic Scissoring is basically a new form of scissor rendering that can divide the workload into multiple pieces of different sizes to keep the workload as even as possible for each GPU, the load balancing can be adjusted every frame. It is intended to be as widely compatible as the standard Scissor rendering method.
Alternate Frame Rendering: Renowned as the fastest rendering method, AFR can nearly double the framerate by having one GPU render the even numbered frames, and the other GPU render the alternate(odd numbered) frames. (Default if a profile exists.) Only downside to it's extreme speed is desync causes shuddering and there's a small lag.
CrossFire Super AA: This rendering mode isn't for improved performance, it is for dramatically higher IQ(Image Quality) by doubling the effective AA(Anti-Aliasing), the graphics cards have different sampling patterns.
If your CPU is bottlenecking a single GPU you won't see any gains from sticking in a second GPU. CrossFire likes high resolutions with lots of AA, if you don't have a significant graphical demand, you're putting them to waste, they also scale better with greater demand.
Power! / Price!
You pay twice as much, you get nearly twice the performance... not a bad deal, however, CrossFire is costly once you factor in power consumption, the need for a decent motherboard, and the need for a sufficient power supply.
Mixing GPUs!
Unlike SLI, you CAN mix GPUs, but you'll only go as fast as if you had two of the weaker, an easy solution is to just overclock the slower one, flashing the video card's BIOS is a permanent method, but software overclocking gets the job done, Catalyst Control Panel gets the job done.
Compatibility chart below.
Multi-Monitor Support!
Nowadays it DOES support multi-monitor to an extreme.
EyeFinity is the marketing name for multi-monitor-deliciousness a single 5800 GPU can drive up to 6 displays, 2 in CF could drive 12.
WHAT IS CROSSFIRE?
"CrossFire" is the brand name of ATi's multi-GPU solution, it's competitor, SLI a technology developed by rival nVidia.
Before branded as a commercial multi-GPU solution, CrossFire was known as AMR(ATi Multi-Rendering), a solution primarily used by Evans and Sutherland for commercial flight simulators created in early 2002.
After a after a major overhaul of architecture in mid-2005, "AMR" was then branded as ATi CrossFire and released on September 27, 2005 as a solution to compete against SLI.
There are currently 2 forms of ATi's Crossfire platform; one which requires internal bridges, and the lower-end software method.
CROSSFIRE VARIANTS:
Dongled' CrossFireThe last graphics card to use this method was the X1900XTX. A master card and a large cord connecting the two cards externally was required.
Internally-Bridged Crossfire "Native CrossFire" - Now called CrossFireX
Allows the use of internal bridging with a ribbon-cable similar to SLI's method of connecting GPUs together.
There are 2 bridge connection slots on each card and there is no predefined limit as to how many GPUs can be CrossFired together, the current limit is 4 GPUs, which meas 2 dual-gpu cards like the 5970/4870X2, or 4 single-cpu cards. No master card is required, No more dongle. Your only concern is having a bridge for 2 cards, or 2 for triple, or 3 for quad cards. They come with graphics cards or motherboards, if you're interested in CrossFire make sure to keep an eye out for that or you'll have to buy separately.
Software Crossfire
Who needs bridges or dongles when you have a PCIe bus that has plenty of bandwidth?
Software Crossfire is generally intended for lower end GPUs, integrated and dedicated cards that do not require any more bandwidth then what the PCIe interface can provide for them to communicate.
How Good Is CrossFire?
Is it worth it? How much of a performance gain is possible?To do: Get accurate(unbiased/up-to-date) benchmarks.
EDIT: No you.
CROSSFIRE RENDERING METHODS:
SuperTiling: The image is distributed to the rendering GPUs with a checkerboard pattern to evenly distribute the workload.(default if supported)
Scissor: Similar to SLI's default rendering method, Scissor horizontally divides the rendering view into one chunk per GPU/
Scissor(dynamic): Dynamic Scissoring is basically a new form of scissor rendering that can divide the workload into multiple pieces of different sizes to keep the workload as even as possible for each GPU, the load balancing can be adjusted every frame. It is intended to be as widely compatible as the standard Scissor rendering method.
Alternate Frame Rendering: Renowned as the fastest rendering method, AFR can nearly double the framerate by having one GPU render the even numbered frames, and the other GPU render the alternate(odd numbered) frames. (Default if a profile exists.) Only downside to it's extreme speed is desync causes shuddering and there's a small lag.
CrossFire Super AA: This rendering mode isn't for improved performance, it is for dramatically higher IQ(Image Quality) by doubling the effective AA(Anti-Aliasing), the graphics cards have different sampling patterns.
Things to Consider Before You get In The CrossFire:
Bottlenecks!If your CPU is bottlenecking a single GPU you won't see any gains from sticking in a second GPU. CrossFire likes high resolutions with lots of AA, if you don't have a significant graphical demand, you're putting them to waste, they also scale better with greater demand.
Power! / Price!
You pay twice as much, you get nearly twice the performance... not a bad deal, however, CrossFire is costly once you factor in power consumption, the need for a decent motherboard, and the need for a sufficient power supply.
Mixing GPUs!
Unlike SLI, you CAN mix GPUs, but you'll only go as fast as if you had two of the weaker, an easy solution is to just overclock the slower one, flashing the video card's BIOS is a permanent method, but software overclocking gets the job done, Catalyst Control Panel gets the job done.
Compatibility chart below.
Multi-Monitor Support!
Nowadays it DOES support multi-monitor to an extreme.
EyeFinity is the marketing name for multi-monitor-deliciousness a single 5800 GPU can drive up to 6 displays, 2 in CF could drive 12.
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