8800GTS 512MB is G92 AKA naked core no?

The thing is, when you use Xigmatek Battle-Axe VD964 on naked core based GPU, only 2 heatpipes were in contact with the GPU.

Seriously, Xigmatek Battle-Axe VD964 is only good for Nvidia G80 GPU based graphic card since Nvidia G80 is the only GPU that has IHS [Ignoring the old-old GPU lah].

It'll be better if you have any of those G80 graphic cards together with the Battle-Axe & HR-03 Plus to compare.

HR-03 Plus has 6 heatpipes with non HDT technology.
Battle-Axe has 4 heatpipes with HDT technology.

Kinda hard, as most of us have left G80 for a very long time.

I'd choose Battle-Axe over HR-03 Plus.
I believe Battle-Axe will win on both performance & price matter.

With Battle-Axe, you don't have to buy any fans. Plus, Battle-Axe comes with two fans, which it blows directly to the whole card.
While for HR-03 Plus, you still need to buy a 92MM fan while still not being able to cool the whole card as the 92MM fan will only be blowing to the middle of the card.

If you compare between HR-03 Plus & Auras Fridge JES988, HR-03 Plus would be better since HR-03 Plus has 6 heatpipes.
But if you compare HR-03 Plus, Fridge JES988 & Battle-Axe VD964 on an 8800 Ultra, Battle-Axe would be the real performer.

This is because your 8800 Ultra GPU has it's own IHS, thus all 4 heatpipes from the Battle-Axe will get in contact with the 8800 Ultra GPU directly.

Battle-Axe is the best choice for your 8800 Ultra since your Ultra has IHS which can help spread the heat directly to all 4 heatpipes on the Battle-Axe.
Plus, Battle-Axe is the cheapest among all 3.

Do remember that HR-03 Plus & Fridge JES988 doesn't come with a fan.