First of all laptops aren't made to swap out motherboads and the cases are specifically designed for the motherboards they they come in all sizes and shapes. Second your system is is old about 3 generations of Intel processors have replaced that technology. As part of the technology the clock speeds of the processors haven't changed much since the T3500 2.10 processors. What has changed is the thread and cores have increases as a result the data is processed at the same speed but the path to process data has increased resulting in being able to process more data. Also Intel has built an overclocking into the processors that allow the processors to use faster clock sppeds when needed. My advise is to purchase a new system. The i7 processor quad core with 8 threads is the most powerfull laptop processor.

http://www.intel.com/content/www/us/en/processor-comparison/compare-intel-processors.html