Introduction

As you know, NVIDIA Corp. has recently rolled out a new series of mainstream graphics processors to replace the obsolete chips of the GeForce FX 5700 line. For our detailed report on the capabilities and features of the new GeForce 6600/6600 GT GPUs follow this link. Our second report on the subject was about the performance of the new products in games and benchmarks. The review you’re now reading is going to provide yet another point of view on the new GPU series – that of the overclocker. That is, I’m now interested in how “power-hungry” and “hot” the GeForce 6600 GT is, how much power it consumes. I will also examine the overclockability of the sample we have in our test lab and will try to increase it with a volt modification, i.e. by increasing the voltage of the graphics core.

NVIDIA GeForce 6600 GT

The GeForce 6600 GT inherits the architecture of NVIDIA’s GeForce 6800 series chips but differentiates from them in having half the vertex and pixel pipelines and being manufactured with a thinner 0.11-micron tech process.

The memory bus of the GeForce 6600/6600 GT has also been dissected – 128 bits are left instead of the 256-bit bus of the GeForce 6800 series. The top GeForce 6600 GT model comes with high-speed GDDR3 chips, while the low-end GeForce 6600 is equipped with ordinary TSOP-packaged DDR SDRAM.

We received a reference sample of the GeForce 6600 GT for our tests.

You should already know from our reviews that new GeForce 6600 GT graphics cards are superior in speed as well as in functionality to products on GPUs of the previous generation, the GeForce FX 5700 series. It is a remarkable fact that the new cards appear simpler in design and smaller in size than the older ones: GDDR3 chips have termination circuitry inside themselves, while the use of advanced components in the voltage regulators has lead to simplification of the voltage circuitry.

The back side of the PCB is covered with a shield. You can see details of the GPU and memory voltage regulators and a scattering of small surface-mountable components, mostly ceramic capacitors, there. The biggest chip on the back side of the PCB is the Philips SAA7115HL that’s responsible for digitizing the signal from the card’s video input.

The SLI connector is located at the upper edge of the card; it allows linking together two graphics cards. This feature is of small importance now as there are no mainboards with two PCI Express x16 slots, but the potential opportunity of building a SLI configuration around a mainstream graphics card is nice as it is.

But let’s get back to the card. It is based on the NVIDIA GeForce 6600 GT graphics processing unit that operates at a frequency of 500MHz.

The snapshot shows there are no AGP-to-PCI Express bridges on board or on the GPU’s wafer. PCI Express support is an inborn possession of the GeForce 6600 GT.

The reference card carries 128MB of 2.0ns GDDR3 memory from Samsung:

The nominal frequency of the graphics memory is 500 (1000DDR) MHz. The memory chips have no cooling system proper – they are supposed to be cooled by the air from the GPU cooler:

The contact spot of the heatsink looks like the rest of its surface: there are no copper insertions or polishing:

The cooler as if says, “This graphics processor is a cool guy”. In any case, the cooling system doesn’t look as mighty as the reference one on NVIDIA GeForce 5900 Ultra/5950 Ultra cards. Mark that the GeForce 6600 GT is obviously better than these two monsters in performance. Well, you should already know everything about the performance characteristics of the GeForce 6600 GT (in synthetic as well as real-life tests), and it’s time you knew everything about its power consumption and heat dissipation.

I’ll try to assist you in finding this information.