Macopinion

Have Penryn Chips Licked The MacBooks’ Heat Problem?

One of the major factors that's been holding me back from upgrading to a MacIntel 'Book has been the latter's heat-generating capacity, or more precisely, the level of fan activity associated. While the actual physical temperature of the computer's contact services would also be a significant issue for folks who use their 'Books a lot in literal laptop mode (no longer recommended by Apple for precisely this reason), it's not so much for me, since I mostly keep mine elevated on a laptop stand with an external keyboard, and when I do anticipate a laptop computing session, it's no hardship to grab my Lapworks Futura laptop desk and stuff it can the backpack with the computer.

However, I really, REALLY detest fan noise. I suppose it's partly what your baseline for "normal" is. Folks who came to Mac notebook computing in the 1 GHz plus G4 or MacIntel eras, may be wondering what I'm going on about. The machine heats up; the fan kicks in; right? Well, it wasn't always that way.

My first Mac laptop, a PowerBook 5300, didn't have a cooling fan at all and definitely didn't need one. It never got more than a moderately warm to touch. The first Apple 'Book that came with an internal fan was the Power Book 3400c in 1997, but it rarely ever came on. Ditto for the WallStreet PowerBook I bought in early 1909, whose fan only activated once during normal use in nearly nine years of service, just before the processor failed in a terminal meltdown at the 3.5 year mark (I replaced the processor card, never had any more trouble, and the fan never came on again). The fans in my two Pismo PowerBooks and my G3 iBook have been almost as non-imposing, cutting in only on the very hottest days during prolonged and intensive processor activity, even after I upgraded both Pismos to 550 MHz G4 processors. In fact, I don't recall the fan ever having spooled up in the most-recently purchased Pismo. So my experience with these blessedly quiet Macs imprinted a paradigm of what should be normal for me, and my 1.33 GHz G4 PowerBook was thus a rude awakening, with its fans running almost half the time unless I set the processor speed at "Reduced" in the Tiger or Leopard Energy Saver preferences panel.

it's not that I completely noise-phobic I do enjoy peace and quiet - it's one of all the reasons why I choose to live in an isolated rural community. However, I get pleasure from some sounds - music I like, obviously - or the burbling rumble of a V-8 engine. This isn't as eccentric as it might at first sound to people who don't share a passion for automobiles. For some of us, the sounds or "notes" of, say, a V-8 breathing through low-restriction dual exhausts are literally musical and appreciated as music. Certain types of tone sequences, especially harmonics, are pleasantly anticipated, notably rising and falling patterns like musical scales or an engine climbing through its rev range, falling with each gearshift and rising again. The musical quality of an exhaust note corresponds to cylinder firing order, frequency, and its multiples, or harmonics, which is why some engines, such as inline sixes, V8s and V12s, are more harmonious to the appreciative human ear than V6s or V10s. Of course, not everyone has the same taste in conventional music, either. I digress.

Anyway the high-pitched sounds made by high-RPM. electro mechanical devices like electric motors and cooling fans are unmusical to my ears.

I've been reading some road test reports recently about the new, all-electric Tesla sports car that's scheduled for commercial lunch sometime in the next few weeks. The Tesla, which incidentally is powered by a 1,000 pound bank of 6,831 lithium ion laptop computer batteries, is actually a more than decent performer, with a 0-60 mph acceleration time of 4.7 seconds, about the same has the BMW M-type roadster or and Ford's factory hot rod Mustang Shelby GT 500, and faster than a Porsche Cayman, while its 125 mile per hour top speed the respectable as well, but as Automobile Magazine's Preston Lerner reports, the whine from the electric motor "gets pretty annoying at elevated RPM." Do tell. Lerner notes that "a generation from now, the high-pitched drone of an electric motor at redline may be music to the ears of car enthusiasts. Not this one however..."

Not this one either, and I don't need to drive a Tesla to determine that the whining powerplant and lack of the good old internal combustion engine sounds that are part and parcel of the high performance automobile experience for me wouldn't irritate me greatly. Just like the howl of my PowerBook's cooling fans.

Consequently, it was a big disappointment back in 2006 when the first reports started rolling in about how blistering hot the new, Intel-powered MacBook Pro and MacBook ran. Naively perhaps, I had been hoping that the switch to Intel processors might actually improve matters compared with the sultry higher- clock cycle G4s, but those first Core Duo units were significantly worse than the outgoing Power PC models heat-wise.

With the subsequently-released Core 2 Duo units based on Intel's "Merom" chip family, the heat problem has been mitigated somewhat, and there was reasonable probable cause to hope that the new 45nm "Penryn" CPU, which is physically smaller and less power-hungry than the Merom, would run significantly cooler yet. Based on early reports on Penryn-based 'Books introduced last month there seems to have been an improvement, but perhaps not the revolutionary one I keep hoping for.

The Road Warrior reader and Mailbag correspondent Derek, who has just replaced a 1 GHz 17" PowerBook with a new 2.5 GHz Penryn MacBook Pro reports:

"This is one great machine. I immediately bought 4GB of RAM from OWC It runs very cool, and the fan has never come on to my knowledge. I've read that it may be running very slowly but to me it sounds just like a quiet hard drive. As one who dislikes noisy computers, this Mac is unbelievable. It's very fast, quiet and cool (right now the processors are at 105 and 102 degrees Fahrenheit after hours of use and multiple programs open, much cooler than my old PowerPC Powerbook."

That's pretty encouraging, and it would be reasonable to anticipate that the 2.1 GHz base Penryn MacBook I'm considering might run even cooler than that.

On the other hand another Penryn report on a MacRumors forum sounds a dissonant note:

"I have finally purchased a new Penryn Macbook 2.4. So far my only criticism about it is related to the heat and fan noise. When I use it for non-intensive applications it is usually fine, being the heat at the CPU around 50°C [122° F] and the fans noise barely noticeable (although if everything is in silence you can hear them in the background as a fluorescent light). The problem comes when I do more intensive applications like playing WoW. Here the CPU heat goes to 80C where the fans reach the maximum speed producing lot of noise and keeping the temperature between 73 and 80 C.....

Ouch! My current 1.33 GHz PowerBook runs at about 50° C (processor bottomside) under normal, general duty use, but easily spikes above that under heavier processor loads, toggling the fans at 58.5° [137° F]. I've never seen it climb above 60° C though, so the Penryn MacBook Pro is evidently capable of running much hotter than my PowerBook. Not so encouraging.

Another report, inauspiciously titled "Engadget tries to fry an egg on Penryn MacBook Pro," notes that "for those of us using those first searing-heat MBP’s, you’ll be happy to know the Penryn MacBook Pro’s are a little cooler (temperature-wise anyway). On average, about 10° F cooler, and the fans run slower and quieter."

Gizmodo's thorough analysis of the Penryn machines concludes that: "While idling, the Penryn MBP's CPU was running at 127° F [52° C] - slightly cooler than the Merom MBP which had 133° F [56° C]. But as for the actual experience, the new Penryn MBP felt much cooler on your lap than the older Merom.

On the other hand..... "While performing a video encode in iMovie with the new Penryn MBP CPU was operating at a temperature of 170° F [77° C]; actually warmer than the older Merom MBP at 165° F [74° c}. The increase in operating temperature during a video encode is likely because the more efficient machine is still doing more work every second at its higher clock rate."

On the brighter side, both are still better than the early MacBooks which would frequently get up to 80-85° C [175° - 185° F]

Anand Shimpi's Anandtech report on the Penryn units observes that "With Penryn, thermals have improved on both of Apple's notebooks which translates into a cooler lap experience. The plastic enclosure of the MacBook doesn’t conduct heat as well as the aluminum MacBook Pro, meaning that it also feels better on your lap. Penryn doesn't produce as much heat as Merom so while the MacBook got warm, it never got hot during extended usage on my lap," which is reassuring in a real-world empirical context.

The bottom line here seems to be that the Penryn update amounts to another incremental improvement in the MacIntel 'Books' heat (and concurrent fan noise) profile, but it's no panacea. That said, there is now no way I would consider buying anything older than the current Penryn machines with the possible exception of the 2.2 GHz Santa Rosa MacBook Pro which does have LED display backlighting.

However, Anand Shimpi reports that patience will be rewarded by even better thermal characteristics later this year, with an upgrade to Intel's next generation "Montevina" chipset anticipated sometime toward the end of this Anand says Montevina will have a lower operating voltage (1.5V vs. 1.8V) than Penryn as well as a faster integrated graphics core in the MacBook) and a lower power chipset and clock speeds ranging from 2.26 GHz to 3.06 GHz. Anand says that "Montevina will be yet another evolutionary step on the way to the Nehalem based notebooks sometime next year" bringing with then a "big performance upgrade."

For the full report visit here:
http://www.anandtech.com/mac/showdoc.aspx?i=3246&p=2

Arrgh! The never-ending dilemma of when to make a system upgrade decision. Patience is a cardinal virtue.


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cmoore@macopinion.com


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