As the HR-03 Plus has no real competition in the high-end air cooling arena yet, we simply benchmarked the temperatures of the stock cooler against the HR-03 PLUS in passive mode, and then in active mode with our 90 mm cooler attached.
We know the 8800 GPU can run hot, but it's hard for us not to get a little uncomfortable when we go over 90 degrees Celsius. And that's precisely what the stock cooler delivers under load - 94 degrees Celsius.
The HR-03 PLUS does an admirable job in passive mode, actually surpassing the performance of the stock cooler at idle by a solid 10 degrees. However, when a load is applied, the passive HR-03 can only muster enough cooling power to keep the GPU just shy of 100 degrees. While this is only four degrees hotter than the stock cooler, I don't think it's something we'd be happy with, even though it's probably within the 8800's tolerances.
Add a fan to the HR-03 Plus, however, and it comes into its own. Temperatures plummet to 54 degrees at idle and 69 degrees at load. The 25-degree delta compared to stock cooler performance is very impressive, and it really speaks to the HR-03 PLUS' brute strength cooling prowess.