I've got the new GIGABYTE GV-N465UD-1GI GeForce GTX 465 installed and it's rocking right along. :) The revived EN9800GT has been packed away as a hot spare, although my fingers are crossed that I'll never need it. Yeah. Right.
Anyway, I wanted to pass along another tidbit about the Asus EN9800GT Ultimate graphics card. The default fan speed is barely high enough to prevent it from melting down -- about 1400 RPM. That fan speed setting basically keeps the GPU temperature at just under 80 degrees Celsius. That is not good, and could be the reason that I started having problems.
And before you ask, yes, my case has great ventilation. Everything else in the case is cool as a cucumber.
Asus supplies an add-on monitoring tool that can control the fan in a better manner, allowing you to choose the built in "automatic" (as in, barely avoiding meltdown) or a more carefully controlled fan speed based on GPU termperature (or a manually chosen constant speed).
My best guess is that the marketing folks wanted the quietest possible fan speed that the card could tolerate. In addition, the Asus monitoring program nags you to install other stuff every time it started up. Yes, the card is several years old, but the same software is still on the Asus support site.
In contrast, the default fan speed for the Gigabyte card is about 2600 RPM, keeping the card below 60 degrees Celsius no matter how I've stressed it (so far). And it is quieter than the Asus, as well.
That being said, I've now found some tools on the NVidia site that provide alternative monitoring and, most importantly, fan control from the NVidia control panel! :)
So, if you have the Asus EN9800GT Ultimate card, get that fan speed up and the temperature down if you want a longer hardware life. And you can probably use the NVidia supplied tools to do it.
Cheers,
Eric