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PCB Design

Nvidia developed another PCB for the GeForce 8800 GTS – it is more compact than the PCB of the GeForce 8800 GTX. All GeForce 8800 are shipped to Nvidia’s partners ready-made, so nearly everything we’ll say below about the MSI NX8800GTS applies to every other GeForce 8800 GTS as well, be it a version with 640 or 320 megabytes of graphics memory.

 

The PCB of the GeForce 8800 GTS is shorter than the one of the GeForce 8800 GTX: 22.8 centimeters against nearly 28 centimeters. The GeForce 8800 GTS is almost the same size as the Radeon X1950 XTX and even smaller because its cooler does not stick out beyond the dimensions of the PCB.

Our sample of the MSI NX8800GTS has a green PCB but the company’s website shows a photo with a black PCB. Currently, GeForce 8800 GTX and GTS are selling in both black and green varieties. Notwithstanding all the rumors spreading over the Web, there is no difference, except for the color, between such cards, which is confirmed by Nvidia’s official website.

The black coating is rumored to be more toxic than the traditional green. Some people also say the black coating is more expensive or harder to work with. We don’t agree with any of these suppositions. Soldering masks of different colors cost the same money, so there should be no problems with masks of particular colors. We guess the explanation is simple. Cards of different colors are manufactured by different contract manufacturers, Foxconn and Flextronics. Moreover, Foxconn seems to be using both colors of the coating because we’ve met both black and green cards from that manufacturer.

The power circuit of the GeForce 8800 GTS is almost as complex as the one of the GeForce 8800 GTX and includes more electrolytic capacitors even. It is packed more densely, however, and has only one additional power connector which helped make the PCB shorter. The GPU power supply is controlled by a digital PWM controller Primarion PX3540, the same as on the GeForce 8800 GTX. The memory power supply is controlled by an Intersil ISL6549 controller, which is absent on the GeForce 8800 GTX that has a different memory power circuit.

The left part of the PCB with the main components of the card (GPU, NVIO, memory) is in fact identical to the GeForce 8800 GTX which is reasonable because developing a new PCB from scratch would require more money, time, and effort. Moreover, it would have hardly been possible to simplify the PCB for the GeForce 8800 GTS even developing it from scratch because of the necessity to use the same G80 & NVIO combination as on the flagship model. The only visible difference from the GeForce 8800 GTX is the lack of a second MIO interface. Instead, there is a seat for a technological connector with fixing locks that perhaps serves the same purpose, but is not soldered on the card. The 384-bit wiring of the memory bus is retained even. The reduction of the bus to the necessary width is achieved by simply installing 10 GDDR3 chips instead of 12. Since each chip has a 32-bit bus, 10 of them give you a total of 320 bits. Theoretically, there is no obstacle to creating a GeForce 8800 GTS with a 384-bit memory bus, but we doubt this is a plausible thing. We are more likely to see a full-featured GeForce 8800 GTX with reduced frequencies instead.

The MSI NX8800GTS-T2D640E-HD-OC carries ten GDDR3 memory chips from Samsung (K4J52324QE-BC12, 512Mb capacity, 1.8V voltage, a rating frequency of 800 (1600) MHz). According to Nvidia’s official GeForce 8800 GTS specification, this card’s memory should be clocked at 800 (1600) MHz, but the discussed version of the MSI NX8800GTS has the letters OC in its name. They mean that the card is pre-overclocked by the manufacturer and the memory chips are clocked at 850 (1700) MHz, increasing the bandwidth from 64 to 68GB/s.

The single difference of the GeForce 8800 GTS 320MB from the ordinary model is that it has half the amount of graphics memory. This card comes with 256Mb chips like Samsung’s K4J55323QC/QI series or Hynix’ HY5RS573225AFP. Otherwise the two GeForce 8800 GTS models are identical to the smallest detail.

The marking of the graphics card’s GPU (G80-100-K0-A2) differs from the marking of the GPU on the reference GeForce 8800 GTX (G80-300-A2). We know that GeForce 8800 GTS may be manufactured using G80 chips that have defective units and/or unable to work at the frequency of the 8800 GTX. Perhaps these things are reflected in the chip’s marking.

The 8800 GTS GPU has 96 active streamed processors (out of 128), 24 active TMUs (out of 32), and 20 active ROPs (out of 24). The reference GeForce 8800 GTS has a basic frequency of 500MHz (a real frequency of 513MHz) and a shader processor frequency of 1200MHz (a real frequency of 1188MHz), but the MSI NX8800GTS-T2D640E-HD-OC works at GPU frequencies of 576MHz and 1350MHz, which corresponds to the frequencies of the GeForce 8800 GTX. We’ll see in the Tests section what effect this frequency increase has on the graphics card’s performance.

The NX8800GTS has a standard configuration of output connectors: two DVI-I connectors capable of working in dual-channel mode, and a universal 7-pin mini-DIN connector to connect to HDTV devices via YPbPr and to SDTV devices via S-Video or Composite interfaces. Both DVI connectors of the MSI card are covered with rubber caps for protection.

 
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