Hello everyone, I think a thread about the 3 CPU options available is important as there is a lot of speculation on if those little boys will be able to sustain good performances. First here are the 3 CPU used by Apple. As wee can see, they frequency and TDP is selectable by the manufacturer, however the turbo boost is chip independant. At the end there is only 2 difference: With the entry level, the H5300 is underclocked in comparison to the 2 other versions With the CTO option, the chip has 2 security features that may even not been use by Apple (so this point is irrelevant). The entry level (Core-M 5Y31) has a base frequency of 900Mh with a TDP of 4.5W, but has a max base frequency of 1.1Ghz (the base frequency of the Macbook) and thus will inherit max base TDP of 6W. Thus, the entry level CPU might produce the most heat (as all other would run on "mid-TDP" @ 5W). Now let's talk about how the processor behave: The CPU is not fan-cooled which means that the dissipation is made thanks to the metal body (Alu?) and thus, even with a very low TDP of 5W, the case might go a bit hot when there are heavy tasks. The other point it that because of this cooling method, the CPU will not be able to do intensive task in turbo boost for a long period of time, however it will be super capable of everyday task. (Internet, Office processing, Photo, Video playback etc.) On my rMBP I tried to play some heavy MKV to see the CPU usage: I played 3 30Gb+ movies at the same time and my i5 2.6 whas not even used at 20%. However, my main concern is when watching streaming videos in HD like on The Verge: The player is in flash and thus a simple HD video was using 60-70% of my CPU. My rMBP was super hot... In the later scenario, the Core M might want to go in Turbo boost to play this which could give a bad user experience as the computer would go a bit hot, and the chip might not be able to achieve a smooth playback experience? Should you get the 1.3Ghz CTO? In my opinion NO: The normal price for a CTO CPU is between 83€ for a small bump and 190€ for a large one (in France at least). Apple will be probably following this rule and ask for around 100$ for this option. When looking at the extremly few benchmark available, the gain of 100Mhz is less than 10% and this is under full CPU load! As I explained, the CPU will not be able to sustain full load for a long time (1 minute max if we are optimistic) and thus the benefits will not being seen in normal usage. I would rather recommend the people who want the best "bang for the buck" to stay with the high non-CTO model (1.2/512Gb). That will be my choice! I hope this post can create a constructive discussion as the CPU capabilities are my main concern and I have passed the last few hours on reading products review that are using Core M chips. Edited to add the third point to the list.