GeForce 6600 GT: Taking a Closer Look
Fresh out of its antistatic package, the card surprises with its simple and compact design, not peculiar to modern semiconductor produce. The eight-pipelined cards of the last generation like GeForce 5950 Ultra or RADEON 9800 XT looked much more complex devices. Well, they also had a 256-bit memory bus, while the PCB of the GeForce 6600 GT carries the wiring for a 128-bit bus only.
Even in comparison to the RADEON X600 XT, the card looks empty, as the shield occupies most of the face side of the PCB. You can only see the wiring for the memory as well as the simple circuitry of power filtering and regulation. The card has no additional power connector, although there’s place left for it on the PCB. Thanks to the 0.11-micron tech process and the ability of the PCI Express bus to supply up to 75 watts to the connected device, there’s no need in attaching additional power to the GeForce 6600 GT. That’s good as it makes the installation process easier and frees one PSU connector for another gadget in your system. However, NVIDIA recommends that you use your GeForce 6600 GT card in a system with a high-quality 300W PSU. That’s a justified requirement as low-quality cheap PSUs don’t provide the necessary stability of the voltages. Moreover, such units don’t always honestly comply with their own specs and their design is often simplified. Under a high load, such a unit may crash by itself or with your whole system.
The connector for a special adapter that unites the two graphics cards in the SLI mode is located at the top left corner. The PCB also has a landing place for a second DVI connector, so we may probably see a version of the GeForce 6600 GT with two digital interfaces – especially for owners of two LCD panels. The release of a version with two D-Sub outputs is less likely, although conceivable.
There’s a scattering of small elements at the back side of the PCB, although the shield occupies most of it, too. The Philips SAA7115HL chip is responsible for TV input; the GPU itself takes care about outputting the TV signal.
The GPU cooler is rather untypical for NVIDIA, who has been equipping its products with the so-called blowers exclusively since the GeForce FX 5800. With all their efficiency, blowers can’t boast a very quiet operation. In this case, however, we have a simple axial fan with seven wide transparent blades.
We had a reference card, so there is no highlighting or other special effects here. We are sure, though, that many manufacturers will equip their versions of the GeForce 6600 GT with original coolers and exquisite LED patterns.
The simplicity of the cooling system is directly linked with the 0.11-micron tech process. The graphics processor, manufactured with so thin a process, won’t heat up much, even at 500MHz. There’s still no tachometer, and the fan speed is constant, unlike with the GeForce 6800 cards. The cooler is fastened with two “classic” spring clips. You should be careful when installing the cooler: there’s no frame to protect the GPU die from chipping, and there’s a danger of misaligning the cooler – its fastening lacks stiffness.
Here’s what we have under the heatsink’s sole:
The die of the new graphics processor is rather small, thanks to the 0.11-micron tech process again. Our sample is marked as NV43; it is A2 revision and was manufactured in the 29-th week of the current year, i.e. at the end of July.
The memory is not cooled at all – a sad negligence about chips that work at 500 (1000DDR) MHz, even though GDDR3 generates less heat than DDR/GDDR2. Theoretically, the memory should be cooled down by a stream of air from the GPU cooler, but this stream is too weak to be of any effect. As a result, the memory chips are very hot, although not as much as to scorch your fingers. Well, the problem of cooling is yet to be discussed, since we only deal with an engineering sample now. NVIDIA’s partners may come up with their own cooling systems, more caring about the memory.
The memory is FBGA-packaged and marked as “K4J55323QF-GC20”. According to Samsung, the manufacturer of the chips, this means GDDR3 with 32x8Mb organization, 2v voltage, 2ns access time and a rated frequency of 500 (1000DDR) MHz.
The chips are clocked exactly at their rated frequency on this card. Four chips with that organization make up 128MB of graphics memory, accessed across a 128-bit bus with a peak bandwidth of 16GB/s. The memory subsystem of the GeForce 6600 GT looks very similar to that of the GeForce FX 5800 Ultra where NVIDIA employed same-frequency chips and same-width bus. You may remember that the memory subsystem was among the basic disadvantages of that graphics card. However, this time we deal with a mainstream, inexpensive and much more powerful product than the wretched GeForce FX 6800 Ultra, which was positioned as a top-end solution. Mainstream graphics cards have always had a 128-bit memory bus, so there’s a case of historical justice here. ;)