http://www.tomshardware.co.uk/value-pc- ... 62-13.html
Here is the Best value conclusion on all the above mentioned builds.

Best Value Conclusion

People often discuss efficiency in terms of energy, but cost efficiency replaces performance per watt with performance per dollar. That calculation method is certain to provide a numeric value, but doesn’t indicate whether or not the product is suitable to any particular market. Thus, the following chart must be accompanied by a full examination of each system’s ultimate capabilities.

The cheapest PC normally wins any value comparison and is thus used as the baseline (100%) for comparing all others. However, its value win this month is rather small, at 3% over the $1,300 PC when both are used at their stock speeds. Yet, the cheapest system was also the one with the most factory-underclocked CPU, responding most aggressively to the overclocking efforts of its builder.

This is the point where questions about the adequacy of such a cheap system would normally center on a look at gaming capabilities. But Paul Henningsen surprised us by fitting two formerly high-end Radeon HD 4870 graphics cards and the enormous power supply needed to support these within the tight confines of his budget. The $700 system breezed through most games at a super-tough 2560x1600 pixel resolution, and was able to add advanced features at playable frame rates when dropping to a still-respectable 1920x1200 setting. Indeed, only the fussiest gamers need more.

Instead, we must look at our productivity suite to see that the $700 really is slower in daily use. All three systems were built as full-function performance systems rather than purpose-built gaming machines, and users who do real work on their systems will definitely be disappointed by the cheapest system’s Pentium E5300 processor, even when overclocked. It also comes up a little short in the area of storage for an all-purpose machine with 500GB of capacity, though a larger drive could be low-cost upgrade.

But the biggest strike against the $700 PC’s value win is that its inexpensive Radeon HD 4870 graphics cards are no longer available, and that the next model up adds $50 per card to the budget of anyone trying to replicate this system. An $835 actual price would have allowed the $1,300 PC to match it in today’s value charts.

The real winner today is Don Woligroski’s $1,300 machine. With an extra 140GB storage and an application-boosting Core i5-750, the majority of users should be quite pleased with its overall usefulness. Its Radeon HD 5850 graphics cards performed almost on-par with the Radeon HD 5870 cards used by the $2,500 machine, and it even beat the bigger system in a few benchmarks. Best of all, its excellent initial value is matched by energy efficiency that increases its value over a lifetime of operation.

Finally there’s the big loser of today’s comparison, the $2,500 build. When faced with the choice between SSD drives with inadequate capacity or high-capacity drives and no SSD, its builder picked the fastest-possible desktop hard drives as a compromise. But those drives are twice as large as most power users really need and, at three times the cost of slightly slower 1TB models, are both overkill and overpriced. This expense could have been put to better use in motherboard selection, as it appears the dual x8 pathways of its LGA 1156 platform are simply too weak to provide adequate bandwidth to such powerful graphics cards. Chosen for supposed overclocking superiority, its Core i7-860 processor was surprisingly inferior even to the $1,300 system's Core i5. Although, with no guarantees in overclocking, this may have been simply been "bad luck."

The $2,500 build wasn’t a total failure. Parts that continued to impress us with superb quality and excellent value include its Crucial DDR3-1333 memory, Lian-Li LanCool PC-K7B case, and Corsair CMPSU-850HX power supply. Combining these parts with an X58-based platform and an overclocked Core i7-920 processor could have allowed the Radeon HD 5870 graphics cards to approach their true performance potential. Yet this discussion is merely a distraction from today’s true winner, Don Woligroski’s $1,300 performance, efficiency, and value masterpiece.