We had some pretty good success with the overclocking. The Leadtek SLI pair was able to stay stable at a 580 Mhz core clock and 1.16 Ghz on the memory clock. Pushing the core further resulted in artifacting. This bodes well for those looking to squeeze every last ounce of performance out of their cards as our success with the 3D1 was a bit on the limited side. 
Conclusions
Leadtek has gone with the no frills reference board approach on the hardware side with their WinFast PX6600GT TDH. Their fan choice is a step above the reference solution with a slightly greater diameter but subjectively slightly lower volume. For those fussy end users who like to see copper heatsinks, funky PCB colors and LEDs, the WinFast card will probably not be their first choice, but for those who are more concerned about performance, the Leadtek does not give up anything to either a recently reviewed Gigabyte 6600GT or a reference NVIDIA card we looked at earlier. For those that have not picked up either Pandora Tomorrow or Prince of Persia, the PX6600GT is a nice bonus on the software side as Leadtek has thrown in full versions of both games.
One of the big draws for the PX6600GT and the 6600GT line up in general is the ability to SLI a pair of cards. As we have seen from our benchmark results, there are tangible performance differences and the biggest gains will be in applications that are heavily video bound like Halo and DOOM 3. For all games that support SLI there will be some degree of difference. Something that not all the benchmarks show is how much the 6600GT SLI pair can improve the minimum framerate - this can be clearly seen in our FRAPS run through of a DOOM 3 level. The dips that were seen with a 6800GT get largely smoothed out with the Leadtek 6600GT pair but this is not apparent in the average framerate. We have no reason to suspect that this is not the case in other video limited situations and we would suggest that a 6600GT SLI will provide better minimum framerates in those cases. However, there are three situations where the 6600GT SLI setup is not as useful as a single 6800GT solution
- the processor bound scenario: Because there is an overhead to SLI, in a processor bound situation the frame rate will be lower than a single card solution. This does not really matter when the game is pulling 200FPS in a scene and is processor bound - it matters when the processor is needed to do complicated AI work or physics or whatever else and the framerate is already relatively low.
- the physical card memory limitation: the current implementation of SLI has the same data set sent to both cards which means that the same geometry and the same textures are loaded onto both cards which means that memory is being wasted. A 128MB+128MB SLI solution is not as flexible as a single 256MB card. This can be seen in several benchmarks where the frame rates drop sharply at 1280x1024 with AA/AF and above. This may become more relevant as games like DOOM 3 can take advantage of a full 256MB card (even 512MB if Ultra-High resolution textures are selected)
- compatibility - as we mentioned, SLI is not automatically enabled for all games. The HardOCP article shows that NVIDIA should be remedying this situation with an updated driver release but they do mention that SLI will be disabled on games that have issues with it. This means that ultimately, it is up to NVIDIA or the developer to resolve these issues
A single Leadtek 6600GT provides for some great performance today and there is no doubt that a second 6600GT down the road would be a pretty good upgrade option as the 6600GT SLI pair is in theory more powerful than a single 6800GT. It may also be the case that NVIDIA narrows down the performance hit further. For those that are debating whether a single 6800GT is a better purchase than a pair of 6600GT, the answer to that is not as clear cut and the situations outlined above should merit some thought.
A quick search on PriceGrabber has the Leadtek PX6600GT show up under the 200$ SRP that NVIDIA has set which should make it pretty competitive against other cards. Something that we would like to see from Leadtek and other manufacturers would be the option buy a stripped down second card that comes with nothing but the card to reduce the price and offer the end user even more incentive to go for a 6600GT SLI setup over the 6800GT.
At the end of the day, the Leadtek WinFast PX6600GT TDH a good purchase for those in the market for a PCIe 6600GT and are looking for good overclocking results, a reasonably good price and a good bundle. No, there are no LEDS or copper heatsinks but for those looking for a stock, but solid midrange card, it is hard to go wrong with this one.
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