Cooling

Let's examine ECS Hydra first. It's a SLI kit of two identical cards with a shared Thermaltake cooling system. The kit requires a motherboard on NVIDIA chipset that has two PCI-E x16 slots. (An external SLI configuration, i.e. with two standalone graphics cards, won't work on other platforms.)

Both cards feature liquid-cooled heatsinks as well as optional fans. Each has its own power cable to be connected to a power supply unit.

The card from Zotac comes with a huge unit that contains the heatsink, the pump, and the liquid capacity expansion container.

Zotac GeForce 9800 GTX Zone Edition 512MB
As we have already mentioned above, a part of the cooling system installed on the card itself includes a heatsink, a pump, and a liquid container. Tubes from the card go to the external cooling block, which can be mounted on the rear panel of a PC enclosure (inside) instead of a standard fan. Dimensions of all blocks and parts must be taken into consideration, of course. This card can be installed into relatively large PC enclosures. The pump on the card works very quietly, just like the big fan on the cooling block. So the cooling system is generally quiet, its noise level is acceptable even for those people who love quiet system units.
ECS Hydra 9800 GTX+ 2x512MB
The same operating principle: the pump drives liquid around a closed path, which channels the heat from the graphics cards and then cools in a special heatsink. But this device is more complex, because it has to cool two cards. The cooling block is designed for a 5" bay inside a PC enclosure. It takes up two slots, which must be taken into account before you buy Hydra. The pump and the liquid container are installed in that block. And the heatsink is cooled with a large fan, illuminated blue, which looks great through cut-outs on the front panel. Tubes from the external unit must be connected to special bundled splitters, which in their turn connect to tubes from the heatsinks on the cards. All tubes have In and Out marks, so it's impossible to assemble the system in the wrong way. Fans on the cards are optional (it all depends on core temperatures and overheating). The external block has a single power cable to be connected to a PSU (molex). This pump is noisier than in the previous product, so the cooling system is generally a tad louder. But this fact is irrelevant, as the product is designed for enthusiasts.

There is another difference between these two solutions. In case of Zotac, liquid is already inside the cooling system, and there is no authorized access to it. But in case of Hydra, coolant comes in a bottle. It must be poured into the liquid container before using the card. Moreover, you must not install the external block into a PC enclosure, until the liquid is pumped through all tubes (they are transparent, so you can see the process). You have to add liquid to the block in the process until all the tubes are filled and no bubbles remain in them.

We used RivaTuner (written by A.Nikolaychuk AKA Unwinder) to monitor operating temperatures.

ECS Hydra 9800 GTX+ 2x512MB (each card from the kit)

Zotac GeForce 9800 GTX Zone Edition 512MB

The cooling system from ECS Hydra is expectedly more efficient -- operating temperature of the cores did not grow above 55°C even though these cards operate at a higher frequency. Maximum temperature of the card from Zotac reached 74°C (that's not a critical level). I tried to overclock the cards to a higher level, mind it. In case of ECS Hydra, the maximum level was reached at 820/1950/2300 MHz and 70°C. What concerns the Zotac card -- it was 760/1860/2300 MHz and 88°C. We can see excellent results in the first case, but even in the second case such cooling system shows its advantages.