Series 9 Processor Performance: Mobile Ivy Bridge Delivers
Overall, mobile Ivy Bridge-based processors are only marginally faster than their Sandy Bridge-based predecessors. We covered them in depth in Second-Generation Ultrabooks: Faster And Cheaper With Ivy Bridge. Consequently, the results in our synthetic GeekBench test shouldn't come as a surprise. However, it's interesting to compare performance to the power consumption of these new chips manufactured on a 22 nm node.
The 2.6 GHz Core i5-3320M in Lenovo's ThinkPad X230T bears a 35 W TDP, suiting it to more mainstream mobile platforms able to accommodate larger batteries. In comparison, the 17 W Core i7-3517U in Samsung's Series 9 is built with the more limited dimensions of an Ultrabook in mind. It's the enabler, if you will, of the up-to-nine-hour battery life claims. With that said, performance clearly isn't a problem for the Core i7, which roughly matches (and sometimes exceeds) the more power-liberal Core i5-3320M.
How do you end up with a 17 W Core i7 and a 35 W Core i5 in the first place? Both are dual-core CPUs with Hyper-Threading technology enabled, scheduling to four threads at a time. The Core i7 gets an extra 1 MB of shared L3 cache (4 MB to the Core i5's 3 MB). Where it saves power, however, is its 1.9 GHz based clock rate. The i5 starts at a more aggressive 2.6 GHz. Similarly, the Core i7's HD Graphics 4000 engine throttles all the way down to 350 MHz, while the i5 starts at 650 MHz. Turbo Boost takes both quite a bit higher when the thermal headroom allows, which is one reason we see a close finish between the ThinkPad and Series 9.