CPU cache is memory that is *much* faster to access than traditional memory located across the bus. It's also very expensive. CPUs can make intelligent decisions about what to place in cache so that the most frequently accessed data is in there. There are also things like branch prediction to aid in populating the cache w/the data that is likely to be needed next. In most cases more cache = better, but not always. The CPU will always check its L2 cache prior to fetching the data from memory, so if you are getting a low cache hit rate in a large amount of memory, you are actually getting worse performance than if the CPU went to the main memory immediately.
The CPU will never directly request data from a hard drive as it is simply too slow for a CPU. The OS controls what is placed into RAM so that the CPU can fetch what it needs.
Did I say anything contradictory. Actually, my understanding, from the past knowledge from say 10 years ago when 128 KB of cache was an incredible boost... is that the CPU is accessing the L2 Cache. If L2 Cache doesn't have it the RAM is queried and all info flows into L2 Cache. Yes, if the RAM doesn't have it, whatever is queried is sent to RAM. Then CPU asks for it and immediately cached. This process is about L2 asking RAM and data quickly being moved, near instantly, from RAM to cache. And from Disk to RAM. And from RAM to cache. And so on and so on and so on.
Now, it could have changed, but the metrics are the same as far as I know. CPU works between L2 cache and RAM. That is why it's fast. Everything from HD is queried by RAM. We have to realize how fast this is truly all happening. Like LIGHTSPEED.
This is why USUALLY, more L2 cache will make a BIG difference. This is also why after L2 cache, MEMORY makes a big difference. And after memory, the HD data transfer rate makes a BIG difference.
A lot of people don't realize that SSD in the original MBA was still controlled by a PATA drive controller. This was a constraint. So, people seem to think that the old SSD solves ALL of the problems... NOT TRUE AT ALL. In fact, people thought the problem was that the HDD is PATA and the SSD must not be affected, but it most certainly was. Even the original MBA with SSD was limited severely by the PATA drive controller's technology. The new MBA uses SATA-II technology. So, yes if you buy a revised MBA you may get an SSD, but the reason why it's so much faster then the original MBA is there is a SATA-II controller on the new MBA.
Apple does a great job of making people think you only are buying PATA if you buy the HDD on the original MBA. It only stated SSD for the drive, which was true. But the drive was limited by the drive controller.
This is also why the new MBA benchmarks out much faster by software such as xBench, as an HDD 1.6 GHz new MBA versus an original MBA with 1.8 GHz and SSD.
Problematic... There are lots of little bits and pieces that affect everything. But the whole point is Apple definitely learned its lesson. Unfortunately the early adopters, like me, really got the shaft again from Apple. It has a history of selling new technology that isn't quite right on its first release. The MBA is a perfect example. Apple learned its lesson, and had huge return rates. Incredible problems with the original MBA. The problems were so massive and on every level of the original MBA, that Apple had accepted so many back that it had to lower the price on refurbished (high-end) from $3099 to $1299 in LESS THAN EIGHT MONTHS! That is a big lesson. The problem is people like me who bought it thinking it was a Mac... No, the original MBA was the piece of junk Steve Jobs says Apple could not make for less than $1000. My thinking is Apple sold a lot of us the JUNK it said Apple would never build NOT for $1000 but rather for $1799 to $3099. That really hurt Apple's reputation.
I have bashed the original MBA more than anyone. And I have taken a LOT of heat for it. But I bought the original. It was JUNK. It could NOT do anything any other Mac on the market could do. It had problems with everything and not just video. It was a series of poor choices to use cheap and older technology components rather than the lower voltage chips and the SATA drive and the Nvidia GPU the revised MBA got.
Look, the MBA is alive and well. But can you imagine had Apple never goofed up so badly and just released the new MBA? It would have saved Apple a lot of grief and bad publicity. We all believed Jobs when he told us the original MBA was so great. Did Apple really not test it? Did it really think that those components were not going to equal the trouble it did? Did it think it would be able to rewrite a lot of software like it did with Quicktime to make it easier for the MBA to run videos? Was there quality control problems with thermal paste on the CPUS? Why was it so bad for so many people?
Cool Book has been the ONE THING that I have noticed from reading here that has made the original MBA as a refurbished unit far more successful. AND, the idea people have about not expecting much from the original MBA because they paid for the extreme portability and gave up all of the power. They could use it for very light web surfing, email, and as a Word processor. It did ok for those three things. But it was the WORST MAC EVER as far as being a Mac and running OS X and being able to run the programs and videos that people expected in 2008. Cool Book has allowed a lot of people to use the MBA after buying it for a super cheap price of a $1800 discount for many. And being able to buy it for $999 was just really enticing to people. However, those people for the most part, expected nearly nothing from their MBA. And they were happy in the end because of Cool Book and lowered expectations, NOT by the performance of the original MBA and its inability to perform common basic tasks any Mac user would expect.
The revision B has NO PROBLEMS running HD video. I have run HD video on my MBA using a DUAL DVI cable $100 to an external 30" Apple Cinema Display and the picture was stunning. Looked just like a Mac Pro was driving the display. I have run all types of programs and never had my rev B MBA overheat. NOT ONCE. I use an external ACD with it all of the time. The technology is absolutely amazing. EVERY COMPONENT was upgraded from the original to the revised MBA... and it worked. The revised MBA is a true full blown out Mac capable of running all of the iLife software like video and photo editing. Capable of running Photoshop well. Capable of HD video. Capable of extreme multitasking. Capable of INSTANT app opening when I can recall my original MBA taking 20 seconds to open Safari. I can remember loading CS 3 on my original, and I removed it 20 minutes later, as it could NOT run it at all without lock ups freezing the computer. Without super delays in trying to do ANYTHING with even Dreamweaver.
The revised MBA is for real. If anyone is having problems with their revised MBA it has to be a quality control issue of thermal paste or a damaged component. And maybe some of the larger files have problems opening or playing for the 4200rpm HDD version. But, for the 1.6 GHz or 1.86 GHz with SSD, they absolutely do it all. Everything a MacBook Pro can do.
Only thing you give up is PORTS! From all of the other Macs you lose FireWire, Express Card, multiple USB, Ethernet, and Mic... but you can hook up a 24" ACD and you get three USB ports on the back, and it charges your MBA while you go. It's really like a docking solution. And you also have severely limited drive space compared to the common 320 GB drives currently used by all of the people with lots of huge entertainment files.
And I am so sure many of you are going to rip me on bashing the original MBA. For many the original MBA worked. For most, it did not. Definitely not as a primary Mac. But the new MBA is fully capable of being probably 90% of peoples primary Mac.
Cool Book definitely helps people run the original MBA too. Some people have different experiences with Cool Book I know. But I have to shout out to all of the refurbished buyers that they made a different decision then us original MBA buyers. We thought we were getting a real Mac, and we didn't. The problems were sorta corrected by software changes. But the original MBA could not perform like all of the others in the Mac lineup. However, Cool Book has allowed many to get a $10 application and make their $1299 or $999 MBA run much more like a Mac than had ever been possible before. That is a better decision, because MOST are using as a secondary computer and for some the MBA can do the job when used lightly.
I want to use my MBA just like I would a MBP, and that is exactly how I use it. It costs a lot of money, I know. But it is truly worth every penny in the long run if you can afford a rev B MBA with SSD. Fully capable if you can live with the limited ports.
In all fairness, I use an external 24" LED Backlit ACD, that adds $999 to the price. I also use an AirPort Extreme Base Station with an attached Hard Drive for storage. I cannot fit everything on the 128 GB of drive space, although most non-media enthusiasts probably could. I also spent money on AppleCare, and I do have a backup machine running Windows as I could not waste any space from my MBA with Windows. So, it really does limit me from having one computer like I want. BUT, I only use the other computer one day per month... and my kids get use out of the other. And it's for business so I cannot complain.
So, anyways, I would say, the revised MBA is worth every penny. The SSD is worth every penny if you want speed and power. The 24" ACD is worth every penny if you like to use your MBA like a desktop, and it does the job really amazingly. It really feels no different than a Mac Pro while sitting at the desk. And the AirPort Extreme Base Station is worth every penny, as well as the drive attached. So, it is a big expense, but I think the MBA could be a primary Mac for most people for many years. And the ACD will last longer than the MBA.
So, it it worth it all, yes. For me it's all worth it. But it's also a business expense for me too.
Best wishes to everyone out there. And by all means, if you want a secondary computer, look into the problems with the original MBA, and see if Cool Book is right for you to be able to buy an original MBA for a huge discount and only pay $999 to $1299. The original MBA is better now then ever. With Cool Book and the changes Apple has made, it can work for some as a secondary computer and even other light users as a primary. It all depends on your usage.
GO MACBOOK AIR!
There goes an hour of my life when I could have been sleeping. Oh well. Hope it helps at least one person buy an MBA.
