Ryzen 5 1400 is about 38% faster in general workload. It is even better than i7 2600K. Now in specific scenarios, you can guess this percentage can vary from 5% better to 50% better.
The point that most people miss here is that Ryzen 5 1400 has 4+0 CCX configuration and 10MB cache while the Ryzen 5 1500X has higher clock speeds and extra 8MB of L3 cache in 2+2 CCX configuration. The good that Ryzen 5 1400 has is the absence of "infinity fabric" that locks on RAM speed to interconnect the two CCXs . So in gaming at the same clocks with low speed DDR4 RAM (say 2133mhz or 2400mhz) the Ryzen 5 1400 is cheaper, can OC and also more efficient. But in more complex programs the extra cache would make a difference.
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