Chaintech SA6600G Video Card Review - The Heatsink
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Looking at the heatsink, there is a bit of a letdown. It certainly is more than capable of cooling the GPU at stock speed, but that's about it. There is a caveat though: you must be careful when handling it. The aluminum is held down by three posts, and two rubber pads near the HSI chip. After touching the sink, you easily notice that this is not enough, or at least not enough given how they are configured. The sink rocks easily when you press down on it, breaking any seal between the GPU, the thermal interface material, and the heatsink. Looking at it from the edge, you can also see that it does not cool the memory chips one iota. In fact, it might make them even hotter by trapping in heat, and not allowing any kind of air flow over them.
When I removed the sink to get pictures of the core, I replaced the interface material with my usual razor thin layer of Artic Silver. Putting on the sink again though, and looking at it with some back lighting, I could see that it wasn't even contacting most of the GPU. I had to add mountains of AS to ensure that there was a reasonable amount of contact upon re-attaching the HSF a second time.
Part of the problem comes from the HSI chip itself. It must get hot too, because the sink extends to cover it, and there is a real thermal pad (as opposed to the goop on the GPU) there to transfer heat. This is the reason for it not following the generic 6600GT design. Apparently cooling the converter is more important than the RAM, or even the GPU properly. Finding an aftermarket heatsink is going to be interesting, since it also will have to be capable of dealing with that HSI chip. All things considered, at stock speed none of this should be an issue, and it is pleasantly quiet to the ear. Overclocking is another matter.
Another change from the PCIe version is the addition of a four pin molex to power the device. While the PCIe spec allows enough current to go through the bus to power cards up to 75W, AGP does not. So it's not from the AGP 6600GT being more of a power draw than its sibling; the interface that it is attached to is just designed for older, less energy consuming cards. At least it's only one, as opposed to the TWO found on 6800 Ultras.
Speaking of power, the card normally sits at 300MHz core, and 900MHz memory in 2D mode to draw less current. When the driver detects that you've moved to something needing the full power of the card, it zips the core up to 500MHz (or whatever frequency you've set in Coolbits). Memory clocks remain the same in both modes of operation.
Speaking of drivers, it's nice to have access to nVidia ones again. With the introduction of the "Catalyst" unified driver architecture, ATi has made great strides forward. But there still is a functionality gap, and it's in favor of the American company. This is especially true when looking to disable "optimizations." If you desire pure trilinear filtering, the drivers do allow you to turn off the advanced algorithms that determine if and where it's needed. The same is true of anisotropic filter optimizations. I left both on, as I couldn't discern any obvious visual hints that they were "cheats" as opposed to "optimizations." But the option is at least there for the truly cynical amongst us.
Also present is nVidia's "Digital Vibrance Control," an advanced contrast and color mechanism. While I found that all it did was make my CRT look goofy, it did make the 17" Samsung LCD look much better. For those who aren't able to knowingly and painstakingly adjust visual settings one by one, DVC is a simple one click way to possibly liven up your desktop. If you are really nitpicky though, all of the normal color correction settings are present and accounted for.
One thing I found missing from the drivers was temperature monitoring. Some 6600GT's (such as the MSI model) do have this feature. The diode is physically there; apparently flashing the Chaintech card to the MSI bios is enough to enable it. Hopefully this is something Chaintech does look into, especially considering the instability of the heatsink.
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