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GeForce 8800: Here Comes the DX10 Boom
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The previous issues with Nvidia not being able to do AA with HDR are history. Each ROP supports frame buffer blending. This means that both FP16 and FP32 render targets can be used with multi-sample antialiasing. Under D3D10, eight Multiple Render Targets can be utilized in conjunction with new compression technologies to accelerate color and Z processing in the ROPs.

The GeForce 8800GTX can fill 64 textures per clock cycle, and at 575 MHz, it can serve up a maximum of 36.8 billion textures per second (GeForce 8800GTS = 32 billion/sec). The GeForce 8800GTX has 24 ROPs, and when running at a core frequency of 575 MHz, the card has a peak pixel throughput of 13.8 Gpixels/sec. Similarly, the GeForce880GTS version has 20 ROPs and therefore has a peak fill rate of 10 Gpixels/sec at 500 MHz.

Nvidia GeForce Reference Specifications
  8800GTX 8800GTS 7950GX2 7900GTX 7800GTX 512 7800GTX
Process Technology (nm) 90 90 90 90 110 110
Processor Core G80 G80 G71 G71 G70 G70
Number of Processors 1 1 2 1 1 1
Number of Transistors per Processor (Millions) 681 681 278 278 302 302
Vertex Frequency (MHz) 1350 1200 500 700 550 470
Core Frequency (MHz) 575 500 500 650 550 430
Memory Clock (MHz) 900 600 600 800 850 600
DDR Rate (MHz) 1800 1200 1200 1600 1700 1200
Vertex Shaders (#) 128 96 16 8 8 8
Pixel Shaders (#) 128 96 48 24 24 24
ROPs (#) 24 20 32 16 16 16
Memory Interface (bit) 384 320 256 256 256 256
Frame Buffer Size per Processor (MB) 768 640 512 512 512 256
Memory Bandwidth (GB/sec) per processor 86.4 48 38.4 51.2 54.4 38.4
Vertices/Second (Millions) 10800 7200 2000 1400 1100 940
Pixel Fill Rate (# ROPs x clk) in Billions/sec 13.8 10 16 10.4 8.8 6.88
Texture Fill Rate (# pixel pipes x clk) in Billions/sec 36.8 32 24 15.6 13.2 10.32
RAMDACs (MHz) 400 400 400 400 400 400
Bus Technology PCI Express PCI Express PCI Express PCI Express PCI Express PCI Express

Check out the GeForce 8800GTX/GTS slide show.

If you were scratching your head at the memory bus width, here is your answer. From the core logic image on the previous page, you can see that six memory partitions exist on a GeForce 8800 GTX GPU. Each of these provides a 64-bit interface to memory, yielding a 384-bit combined interface width. The 768 MB of GDDR3 frame buffer memory is attached to a memory subsystem that utilizes a high-speed crossbar design, similar to GeForce 7x GPUs. This crossbar supports DDR1, DDR2, DDR3, GDDR3 and GDDR4 memory.

The GeForce 8800GTX uses GDDR3 memory, with a default clock speed of 900 MHz (GTS version is clocked at 800 MHz). With a 384-bit (48 byte-wide) memory interface running at 900 MHz (1800 MHz DDR data rate), frame buffer memory bandwidth is very high at 86.4 GB/sec. With 768 MB of frame buffer memory, far more complex models and textures can be supported at high resolutions and image quality settings.

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