PCB Design

This is an implementation of the reference PCB design, but with an original cooling system:

The PCB layout has been changed because of the AGP interface. The GPU is located closer to the top edge of the card. The GPU and memory chips are placed at an angle of 45 degrees. By placing them this way it became possible to free some space for the HSI bridge near the AGP connector (as you know from our reviews, the GeForce 6600 natively supports the PCI Express bus only). This imparts a rather queer appearance to the Leadtek WinFast A6600 GT TDH as well as to all GeForce 6600 GT AGP cards.

The cooler had already received our praises for its high efficiency and little noise. It is the same round heatsink with slightly curved ribs abound the perimeter; a 60mm low-speed fan is mounted on it. The fan is very quiet. The cooler?s sole has a protective frame made of some soft material; ordinary white-color silicone thermal paste is used as an interface. The springs of the clips the cooler is fastened to the PCB with are rather tight, thus eliminating the risk of misalignment of the cooler or damage to the GPU core.

Two more such clips are used to fasten the heatsink that cools the HSI bridge. The fan is designed in such a way that its blades don?t compress air under them but rather spread it around. So a portion of the air stream passes through the ribs of the GPU heatsink and cools the ribs of the HSI heatsink, too. These facts all contribute to the highest efficiency of the cooling system deployed on the WinFast A6600 GT TDH graphics card.

The onboard graphics memory is manufactured by Samsung. The K4J55323QF-GC20 GDDR3 chips have an access time of 2.0 nanoseconds and a rated frequency of 500 (1000DDR) MHz, but they are clocked at 450 (900DDR) MHz due to the more complex wiring of the AGP version of the GeForce 6600 GT. The GPU is clocked at the expected 500MHz frequency and contains 8 pixel and 3 vertex processors.