PCB Design and Specs
GeForce 8800 GTS 512MB cards are shipped to Nvidia’s partners in ready-made form, being copies of the reference card. The XFX card is no exception, the sticker on the cooler’s casing being the single difference from the Leadtek WinFast PX8800 GTS 512MB.
The GeForce 8800 GTS 512MB uses a unified PCB design originally developed for the GeForce 8800 GT. The elements of the fourth phase of the power circuit, which were missing on the GeForce 8800 GT, are installed now. The power circuit is based on two controllers: the Primarion PX3544 is responsible for the graphics core and the Intersil ISL6549CBZ is responsible for memory chips. The card carries one 6-pin PCI Express 1.0 connector with a load capacity of 75W. It’s more than enough for the G92 chip that is manufactured on 65nm tech process and has modest power requirements.
The card is equipped with GDDR3 memory (Qimonda HYB18H512321BF-10). The chips are rated for a voltage of 2.0V and a frequency of 1000 (2000) MHz. The card maker didn’t overclock the memory much. It is clocked at 986 (1972) MHz even on the XXX version of the card. Thus, the described graphics card has almost the same memory bandwidth as Nvidia’s reference card. It’s 63.1GB/s to be exact. The card is thus inferior to the GeForce 8800 GTX with its 86.4GB/s in this respect, and memory bandwidth may become a limiting factor for its performance at high resolutions, especially with enabled full-screen antialiasing.
The graphics core is overclocked more: the main domain frequency is 678MHz, and the shader domain frequency is 1700MHz. The core doesn’t have disabled subunits and incorporates 128 unified shader processors (grouped into 8 large modules), 32 TMUs and 16 ROPs. With such parameters the XFX is going to outperform the Nvidia GeForce 8800 GTX across most applications except when you use a high resolution together with 4x FSAA.
The card has two dual-link DVI-I ports and a mini-DIN connector for analog video output. Unlike certain models of GeForce 8800 GT, the card cannot send S/PDIF audio into HDMI. The MIO connector is for SLI technology, but SLI mode is not yet supported well under Windows Vista.
The XFX card carries a new reference cooler developed for the GeForce 8800 GTS. It is based on the most efficient design that used to be installed on Nvidia’s GeForce 8800 GTS 640/320MB. The cooler consists of a large heatsink connected to a GPU-contacting copper base with three heat pipes. The heatsink is cooled with a Delta BFB1012L fan (5.8W). The low heat dissipation of the G92 chip combined with the highly effective heatsink allow to keep the fan speed within reasonable limits. The cooler is silent. The hot air is exhausted out of the system case through the slits in the mounting bracket.
The card has the same thermal interfaces as Nvidia’s reference samples: dark-gray thermal grease for the GPU and fabric pads socked in white thermal grease for the memory chips and power circuit elements. The cooler is fastened securely; no misalignment is possible. We guess the cooler is virtually free from drawbacks. The dual-slot form-factor may be considered as such, but it has long become standard for top-performance graphics cards.