See, an RAM upgrade will give you the power to run more programs without any lag. If your current computer runs without hanging and you just want a speed boost then you may consider an upgrade in the processor. I recommend you to see Intel i3-3200 processor. It is much better then core2duo and not very expensive.
Not enough information.
The Intel Pentium 4 3.0 GHz processor is a single core processor, but if you'd like to upgrade to dual core, have a look at the Intel Pentium 4 531 3.0GHz Processor Upgrade RH008AV.
The Apple MacBook's CPU is a 2.13GHz Intel Core 2 Duo processor with 3MB on-chip shared L2 cache running 1:1 with processor speed.
2.0 GHz.
Intel core duo T7600 is the best
The cost would depend on the processor you wanted to purchase. An upgrade is probably possible (the Pentium Dual-Core is based on the Core Duo and Core 2 Duo processors) but you would need to make sure your motherboard supports the proper FSB speeds for your processor of choice.
The MacBook Pro 15 features a 2.3GHz quad-core Intel Core i7 processor with 6MB of shared L3 cache and Turbo Boost speeds up to 3.3GHz. The integrated Intel HD Graphics 4000 processor boosts performance by up to 60 percent.
It depends on the motherboard. If your motherboard supports core i3, it is possible, if not it isn't.
Depends on the computer. A Macbook Pro can have a quad core processor, older computers can have 2.
The macbook pro is: Width 15.5 in, Depth 10.5 in, Height 1 in
i suggest you upgrade to a i5 or i7 processor as i3 is only dual core. Plus you will need a moderate amount of RAM
A desk top and a lap top computer will use different sizes of core processors. The best core processor for you will really depend on what you need to do with your computer. One great core processor is the six core that comes in many HP computers.