Whether auto-throttling kicks in depends on ambient conditions. When running Mlucas in LL-test mode it hammers the FPU by way of SSE2, and the temperature according to the smcFan app rises from 50C to 80C in under a minute. I notice a significant difference depending on the nature of the code: When running my Mlucas TF code which is highly optimized but 64-integer (as opposed to FPU) based, it gets warm but stays below the auto-throttling temperature threshold. Note the 80C is accompanied by the fan revving to 6-7krpm, and there are no odd noises from it, and a robust warm-airflow out the back vent which tells me the fan is working fine. If I fire up some heavy-duty crunching program the temp very quickly gets up toward 80C, though (on my system) auto-throttling is a serious issue only for highly-optimized FPU-based code. as I write this, internal temp shows 50-60C depending on configuration (bottom elevated or not) and ambient temp/airflow. When nothing significant is running, e.g. Last week I installed a piece of freeware called smcFanControl, which allows me to monitor internal temp and fan speed. Mine is a basic white-plastic-case MacBook (non-pro, that is), which embodies the issue debrouxl notes, the bottom is sealed and the plastic is an insulating material. The use of the stand seems to make a difference. The only problem I've had was that the battery died and I had it replaced at the Apple Store at no cost in 2010. It does get warm, but it has never overheated. Here is a high-tech schematic showing a side view of the A-frame configuration, complete with a Schlieren photograph of the lovely convective whorls of hot air exiting the top of the chimney: I will try running stuff on both CPUs tonight and see if any throttling occurs. My results-file timings show full speed ahead for the entire night, meaning 10-20% more throughput than sitting on my desk in "orthodox" clam-style mode. It looks a bit odd, but works beautifully. One creates a "chimney" effect which maximizes natural convection in aiding the fan: air freely enters the fan intakes (mainly via the porously-designed keyboard) through the open ends of the A-frame, and blows out the top of the thus-created chimney, in the natural direction heated air wants to go. The plastic-shielded underside of the unit, which normally gets quite hot since it is sealed off from airflow and has the plastic housing interfering with heat dissipation, is now fully exposed to the air.Ģ. I call it the "A-frame": simply tip the lid-open notebook onto the 2 long edges created by its opened lid, with the fan vents thus pointing up toward the ceiling. With the nights now being warmer as summer nears, even the latter method is not enough to keep the CPU cool enough to prevent auto-throttling, so I've been trying a few things, and finally hit upon what appears to be an optimum configuration for cooling when the unit is running DC-style code but not being actively used by me. These things are just not intended to run heavy-duty code 24/7.īased on timings and 'top'-based profiling, the only time the code really runs at 100% is for a few minutes after startup, and if I set the lid-open unit next to an open window on a cool night. I have no complaints about the MacBook fan - it sounds as quietly powerful as the day I first used it, and is the best fan I've ever had in a laptop. Even single-threaded is sufficient to get the fan maxed out and the CPU hot enough that it frequently goes into throttle-down mode. It`s fine for normal daily tasks, but I also run my Mlucas code (similar thermal properties as Prime95, big-FFT code which hammers the SIMD unit) on it. In fact I only ever boot into Windows now to use Photoshop, which is an old PC version.Like many laptops, my vintage-2009 MacBook is undercooled. Macs can still crash, some of the things you get used to in Windows and miss can be a little irritating. I thought there would be so many programs or applications under Windows I would miss - but not so. Also the quick start-up and near instant restore from sleep. I like the massive trackpad too much, the keyboard too much, the screen too much. The key question is, for my next laptop, would I go back to a non-Mac even if it was half the price. I've ended up then with two laptops in one, a Mac and Windows. So I went for a MacBook Pro and also bought Windows 7 so I could dual boot. I was always a Windows man too, but couldn't really find a laptop I liked, having tired of the likes of HP, Toshiba etc - and sure Dell have a lot of specs for the money, but always the same issues, screen, small trackpad.
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