Get Radeon HD 7850 2GB, why? Here:
Quoting TechReport conclusion:
Right now, the Radeon HD 7850 2GB offers equivalent performance per dollar to the GeForce GTX 650 Ti Boost according to our 99th-percentile metric. It consumes less power, as well, which makes it easier to cool quietly. Last, but not least, it comes with a much more tantalizing game bundle: Tomb Raider and BioShock Infinite. Given those factors alone, the Radeon looks like the better choice—even if you have to pay a $10 premium over the vanilla GTX 650 Ti Boost.
The 650 Ti Boost has definitely made the 7790 less appealing, though. For $20 more, the Nvidia card opens the door to higher resolutions and detail settings. And there's a good chance the 1GB, $149 version of the 650 Ti Boost due next month will also be quicker than its Radeon competition. Our scatter plots show a negligible difference between the 1GB and 2GB versions of the Radeon HD 7850 at the 1080p resolution and detail settings we used. If there's a similarly small gap between the 1GB and 2GB flavors of the 650 Ti Boost, then Nvidia could very well knock the 7790 out cold.
Quoting AnandTech conclusion:
The performance of the two cards is close at times, but ultimately the GTX 650 Ti Boost spends most of its time trailing the 7850 to some degree, its only lead being in Battlefield 3. With those BF3 results pushing the cards to within 5% of each other on average, otherwise the gap is closer to 8%. As such the GTX 650 Ti Boost is unquestionably the weaker card in our benchmarks, just not significantly so. So for it to be priced under the 7850 is the right move here.
In any case, as a 7850 competitor the GTX 650 Ti Boost is nothing amazing – its price and performance are close to the 7850, a card that has been sitting at its current price for months now – meaning it fills its intended role as a slightly cheaper, slightly slower 7850 competitor, but nothing more. If we had to pick between the two of them the 7850 does look a bit better due to its slightly higher performance and lower power consumption, but most buyers should be happy with either one. As we said in our introduction this is a case of balance being returned to the market – where there was once just the 7850 there is now a viable alternative from NVIDIA in the form of the GTX 650 Ti Boost 2GB.
Ultimately with a card at every $10 amidst a packed market there isn’t any kind of real sweet spot right now, so we don’t have any strong recommendations. For buyers on a fixed budget recent launches like the GTX 650 Ti Boost and 7790 introduce newer and better options at $169 and $149 respectively. Otherwise there’s a clear chain of progression right up to $200, and the best card is going to be the card you can afford.