MacBook Air: 11' or 13'? (aka begging for advise)

Actually, SSDs are still considerably slower than RAM. Even Corsair’s newest 1TB drive still has a peak write speed of 650MB/s, while the PC3 8500 RAM used in the MBA has a peak speed of 8500MB/s. Of course, it’s still quite a bit faster than disk-based drives.

If using more “Virtual Ram” on an SSD drive this may increase the read/write cycles of the drive reducing the overall life of the drive. But since the improvements of SSD write layer technology this is still so far in the future the drive or actual computer would be replaced long before the drive was no longer able to “write” to its solid state layers.

In other words the more you use an SSD drive the faster you wear it out (based on cycles) where mechanical drives are based on “hours” of use and read/write cycles have no impact. But the specifications of most modern SSD drives the cycle life is so large that you could run a server 24/7 on your drive and not hit the read/right danger zone for many years.

Right! I didn’t mean to suggest it is as fast as RAM, that would be virtually impossible due to all of the interface on top of it. The stuff you need to arbitrate a file-system is very abstracted and will not keep up with highly tuned circuitry. But, as you say, the switch to using swaps with SSD is going to be much less noticeable than hard drives; which in my opinion increases the longevity of the system given that 4GB is going to be a lot for a writing machine anyway. There is a lot of room to work in there in the coming years, and if things do get to the point where the OS and a few basic tools are using up that space, the MBA will perform better than an MBP of the same era—assuming no upgrades and strictly speaking from a longevity standpoint.

And yeah, write-life on these modern chips is not a huge concern. You’d have to be pushing the MBA past its limit on a daily basis, hours every day, for a very long time to really see performance drops as cells deplete, due to excessive swapping. I think I posted my findings on this in another thread, but the effective “statistical normal” (not data-centre servers!) use of an SSD drive is in the decades. That’s way better than hard drives, and even way better than non-archival DVD/CD tech (which is of course all based on hypothetical longevity and artificial ageing tests; but we are talking 3–5 years for hard drives, 10 to 20 for cheap CD/DVD writables, 30–40 for SSD, and 100+ for high quality archival DVD/CD which is of course of no use in a computer except as a read-only retrieval).

The rest of the computer will likely be dead by then, not to mention obsolete.

This isn’t strictly Air-related, but I figured it would be a good place, given the talk about SSDs. I have a unibody MacBook and have been vaguely considering the Air. The thing is, it would be a bad idea to go spend $1300 on the 13" model. So I’ve been doing som research on just replacing my current drive with an SSD, since that’s the main reason I’d want an Air in the first place.

Anyone know much about using regular SSDs in OS X? It lacks TRIM support (for whatever reason), so would it be a bad idea to get it?

get a drive from OWC. they make the mercury elite drives and use sandforce controllers (which doesn’t need trim)

OWC loves macs and has ninety million solutions for mac upgrades, even some turnkey, you ship to them and they ship you back, if you aren’t handy.

Thanks for the tip. I’ll have to see how they compare to the Corsair F120, which also uses the Sandforce controller (and is a little cheaper).

according to these guys,, they’re darn near identical except for some heavy workload tests…

it’s the sandforce controller, and making sure that the model you’re getting doesn’t have any odd firmware limitations.

the sandforce drives are super low power and fast, fast, fast

Has anyone used the new MBAs in clamshell mode (external monitory, keyboard, mouse)? I tried using my old MB Pro that way but quickly decided that the jet-engine-like fan-noise was a sign that while possible, it wasn’t an advisable mode of use. All I had to do was watch one youtube video to trigger the fans to go to about 4-5k rpm.

The reason I want clamshell in the first place is that I don’t have desk space I want to devote to a computer next to my monitor, so slipping it under the monitor stand after connecting wires to both sides (USB/FireWire/Power/Ethernet/Video Out) seemed the best way to make room. At the moment, I just set the laptop in front of my monitor, plug everything in while it’s sleeping, and then open it up with no video on the built-in screen. That gives me a keyboard & trackpad, one large screen, and no heat issues.


When I’m at home, I use my MBP (Early 2008) with a 500GB drive and 6GB or RAM that way. I use the nice BookArc support to keep it in the vertical position:

I’ve not noticed any increase in fan noise, nor in temperature. Are you referring to the more recent MacBook Pro?


It makes a pretty big difference keeping a laptop mostly exposed to air instead of a desktop. Since the surfaces that tend to get the hottest are also on the bottom, the open-air side is much less effective at dissipating heat—in fact the whole thermal strategy is to push the heat down and out, so as to keep the typing and tracking surface as cool and comfortable to use as possible. So simply elevating the laptop a few inches, or using a vertical mount as Paolo describes, can make a world of difference.

Cracking the lid open a ways helps, but like I say, most of the heat is going through the bottom, so this is much less efficient than elevation (though it undeniably does make a difference). That’s for MBPs. I know for a long time Apple disabled clamshell mode entirely on MacBooks and iBooks because they did a large portion of their air intake through the keyboard itself. MacBook Pros were designed to intake through other means, and so did not overheat with the lid closed. I’m not sure if this rule of thumb translates to the new MBA though. As well, it runs a lot cooler than a regular MacBook, which has hotter circuitry and a hard drive. So even if it does vent through the keyboard, it doesn’t vent nearly as much, in fact I can hardly ever hear the fan on it, though I know from monitors that they are running at a low RPM at all times.

I’d give it a try, if it allows it. If you can hear the fan audibly kicking in after a bit, then it might be ill advised to continue in clamshell mode.

Air intake issues and heat dissipation are problems. You could go out and buy some gadgets and widgets and what nots but in the end you could just break down and fork out a little dough for a used Mac Mini and just network the two wireless.

Just a thought.

As to KB statements on SSD. Yup SSD is much faster than Mechanical HDS. I saw the comparisons of 15K Seagates versus 64GB SSDs and the speed difference is massive.

As to read write I did read that under normal usage SSD could handle around 39+ years before read write swap concerns. Another one was an SSD under a heavy server workload (24/7 with a lot od database activity) and the SSD was rated to last around 12 years under those workloads.

The nice thing about SSDs is NO MOVING PARTS. Hence in theory you might have some “bombs” but you will never have a true HD crash.

What I would like to see as RAM sizes grow is something like the RAM DISK tricks in the old days. Where you could copy an application to a RAM disk and the speed increase was out of this world. Imagine if you could load the Whole OS into RAM…

oh man… I can remember stripping my system down to nothing, loading it into RAM, and booting from that – WOW it would scream!!! I think that was my Duo 230 that I would do that on, or it was a Quadra in the school lab. All I can remember is that I’d load the System Folder and Strategic Conquest into the RAM disk and I could get the computer to make its turns in Strategic Conquest in about 1/4 the time it’d take otherwise. Could get more full games in that way! :mrgreen:

I can’t imagine what RAMdisk would be like on these machines… holy cow, between the MBA and the i7, these things FLY already… maybe it would induce a speed warp and my mac would pour scotch for me and Scrivener would write for me, too.


maybe it’d make strategic conquest run on the intel macs! (as it is, I have to run it in classic boot on my old G4, but I can’t remember the password for system 9 (!)) anybody, know how to crack that?

Thanks for the link. I wound up getting the Corsair, because the performance is nearly identical (lower than the 3% that’s necessary for human perception :wink:), and Fry’s had a $30 rebate which made it only $200. Looks like hibernation might be a little problematic with the drive (some people have issues with suspend-to-disk), but I prefer sleep anyways. And if it just doesn’t work right, I’ll return it.

You can still do this. I know it’s possible to load the whole OS in Linux, and it looks like you can do some stuff with OS X, too: … -mac-os-x/

Tempting to add 8GB RAM to my system and see what I can do…

make two of them and then tell disk utilities to raid 0 them! hahahaha :stuck_out_tongue:

on the 16 GB systems, that might actually be enough to load the system into RAM totally – take out localizations and stuff (sort of like the bootable DVDs for installing OS X)

Given that none of the photo programs seem too keen on multiple cores, I think the most useful reason for a RAM disk was mentioned in that thread: scratch disks. but when handbrake (which is multi-core aware) can rip+encode to high profile h264 a 2 hr DVD in 20 minutes without RAM disk, it does make me wonder if it can be made even faster with this

more importantly, can I sync my writing ideas to the RAM disk through dropbox, or do I have to archive the thoughts and zip them first?

I have the previous version of the MBA, which I use in clamshell mode with an external BT keyboard and 24" Apple monitor. The fan does kick in, but I haven’t noticed it impeding performance. I have the Air positioned in such a way that the little vents along the bottom are actually exposed to air, not venting directly down onto my desktop, and maybe that helps.

Well, a week in, I’m loving my Corsair F120. Great drive, and crazy fast. Things that took several seconds to load are instantaneous. No hibernation issues here, and my battery life is higher than ever (I get 6 hours if I try, whereas I got 5 before). Reason (for me) to get a MacBook Air: gone.

Wow… that’s good stuff! maybe later this year, after I get my taxes and cash my royalties cough, I’ll drop one in my i7 iMac. I’ve been reading some of the tutorials online where others have cracked the case and added the ssd to the extra bay space… and then there’s the nuts that replace all drives and put 3 ssds in there in raid 0… not sure I need that, but I do know that the ssd in the air has spoiled me.

I’ll be interested how it fairs after activity. everyone complains about diminished performance online, but most of those drive tests I’ve seen on sandforce ssds on macs show nearly no degradation.

Thanks again to all that advised me on the MacBook Air dilemma. I’ve bought the 11’ and I’m very pleased with it. On this same subject I posted a long text on my (new) blog… if you feel up to read more about it: MacBook Air: How do I love thee

Great news, and glad you love it. Even though I have the 13" — and my 17" MBP languishes practically unused even when I’m at home, as this one is so much faster and such a pleasure to use — everytime I see an 11", I think “I’d love one of those!”



PS: I can’t read your blog, I’m afraid … Great Firewall of China, and all that. The Beijing government has toughened up further on internet usage!