They certainly aimed high enough. His memory capacity and brute computational strength are equivalent to a modern super computer.
The fastest computer today, IBM's Roadrunner, is capable of over 1 Quadrillion ops per second under peak operating conditions, about 15 times as fast as Data. It's normal operating parameters are only a fraction of that. Most supercomputers are actually quite a bit slower than Roadrunner, maybe a tenth to half as powerful.
However, Roadrunner has over 20,000 individual processors, occupies 6,000 square feet and consumes 2.5 MW of power. It's not just how fast a computer can operate, but how it operates and how much power and space it consumes. Data's brain is 15 times slower in brute computation (1+1+1.....), but it's also thousands of times smaller. Data's brain does not use brute force calculations to do all he does, that's part of what makes his positronic brain so special. At least that's what I gather. Something to do with multiple layers of parallel calculation, advanced algorithms, etc.
