P8800, P9600, T9550, or T9600?

I have a Lenovo U330 with a U7350. I'd like to upgrade to a faster CPU. My questions are regarding battery life and L2 cache. Since none of the chips I'm looking at are quads, my stock cooling should be sufficent for all dual cores right?

1.) Clock for clock, I've heard that Penryn with 6MB of L2 vs. those with 3MB of L2 are about 8% faster. Can anyone confirm this?

2.) Whatever processor I get, I plan on undervolting it. Both the P chips are rated for 25w, while the T are rated for 35w. Let's say for example that I could get them all running their rated stock speeds at say 1.1v. Would the 3 chips running at 2.66GHz all consume the same amount of watts, while the T9600 (running at 2.8GHz) would consume slightly more. Or would they all consume the same amount of wattage of the vcore is the same? Could I undervolt a T9xxx chip to consume the same amount of energy as a P chip? And would it run any hotter since it's a T9xxx chip?

Thanks

 

1) Extra L2 cache doesn't make much of a difference unless you plan to play games.

2) Given that decreased voltage requires less power, yes the power consumption (wattage) will go down. However, using RM Clock can be a bit unreliable and problematic at times. You could undervolt a T-series to approach the power consumption of a Penryn, but you won't be able to match the power consumption or TDP. Also, the T series would still run a few degrees hotter than a P series regardless of voltage or power consumption, though the difference in temperature is perfectly acceptable as it is within range. Practically speaking, the P series will run a few degrees cooler but this shouldn't matter much unless your computer has cooling issues.

Between the T series and Penryn series, I would recommend taking cost as the top decision-making factor between the two. The Penryn is merely an incremental improvement over the T series in terms of power consumption, performance, and TDP, but the difference in cost is often disproportionately high. By that I mean that the literal cost of a Penryn chip will frequently outweigh the incremental benefits.