The T1 had outstanding throughput with massive numbers of threads supported by the processor, but older applications burdened with single thread bottlenecks occasionally exhibited poor overall performance. Single-threaded application weakness was mitigated with the follow-on SPARC T4 processor. The T4 core count was reduced to 8 (from 16 on the T3), the cores were made more complex, the clock rate was nearly doubled — all contributing to faster single thread performance (from between 300% to 500% increase over previous generations. Additional effort was made to add the "critical thread API", where the operating system would detect a bottleneck and would temporarily allocate the resources of an entire core, instead of 1 (of 8) threads, to the targeted application processes exhibiting single threaded CPU bound behavior. This allowed the T4 to uniquely mitigate single threaded bottlenecks, while not having to compromise in the overall architecture to achieve massive multi-threaded throughput.