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As noted by tonymacx86 (via 9 to 5 Mac), iFixit's teardown of the new iMac released earlier this week reveals that the machine utilizes Intel's BD82Z68 platform controller. The inclusion is notable in part because the Z68 chipset is reportedly not set for public introduction until next week.
Apple use of the Z68 chipset marks yet another exclusive for the company, which has occasionally been granted early access to forthcoming chip components ahead of public unveilings and competitors' offerings.
The Z68 chipset is also notable because it supports SSD caching, a system that marries conventional hard drives to small solid-state drives (SSDs) to provide a seamless user experience with increased performance as the most frequently-accessed files are placed on the speedy SSD.
Apple of course offers SSD options in its iMacs, either as a replacement for or in addition to the traditional hard drive included as standard. The iMac's SSD, however, is a full 256 GB drive rather than the much smaller-capacity drives envisioned for SSD caching. And while Apple doesn't seem to be supporting true SSD caching in the new iMacs, the company achieves a similar but less seamless effect by installing the operating system and applications on the SSD while leaving the traditional hard drive for media on systems configured with both types of drives.
Intel is reportedly preparing to launch its own "Larsen Creek" line of SSDs with capacities around 20 GB and specifically designed to support seamless SSD caching when paired with a traditional hard drive and a compatible chipset such as the Z68. It is unclear if Apple will be looking to incorporate such systems in future hardware, but the company is clearly interested in pursing SSD technology for its performance benefits.
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(View all)Some Z68 motherboard manufacturers have decided to ignore this entirely, such as Gigabyte who dont supply power to the VAXG pin of the CPU - which means the Intel HD GPU is never powered.
I'd love to know what Apple have done. Does their implementation of the chipset/cpu allow OpenCL access to the HD2000/HD3000 on the iMacs?
The Z68 chipset has more functionality than just SSD caching. Check out the writeup from Tom's Hardware: http://www.tomshardware.com/reviews/z68-express-lucidlogix-virtu-ssd-caching,2888.html
A few things I learned from the article:
1. SSD Caching is not the best; it's far faster to use the SSD on its own. It does add a small speed bump when it's "primed" but, when I first read about it, it seemed like a lot of work for little gain, which I could already do better with existing chipsets.
2. The other big benefit, and I think this is even bigger than the SSD angle, is it allows you to access the excellent video transcoding capabilities that are included in the video chip built into the processor while making use of the add-in discrete graphics card to run the display. If they can combine that with Grand Central, that's a whole lot more performance out of the same chip than with a P67.
Is it just me or has Apple been more aggressive with this in the last 12 months or so?
It lets you use a cheap hdd to get speeds similar to an expensive large ssd.
Does this imply that with the arrival of TB supported drives, a cheap HD can be paired with a small SSD for speeds on par with a large SSD? Does TB access the Z68 chipset, assuming TB can be used as a boot drive?
That's the thing. We don't know how Apple has the display implemented in the iMac. They've implemented seamless display support allowing the use of both the IGP and a discrete GPU in the MacBook Pros so they can certainly implement something similar to allow the IGP to be active for QuickSync. As for Virtu, Apple would have to implement something similar themselves due to the different windowing/graphics system from Windows. It'll be interesting to see whether they've done so, perhaps in Lion. Certainly the performance of QuickSync over OpenCL for video encoding makes it worthwhile. Particularly, because all subsequent Intel processor generations look to keep and expand QuickSync support so adding support now will have long-term benefits and its something they will probably have to do eventually anyways.
And I've read the latest version of Virtu virtualizes the IGP rather than virtualizing the discrete GPU as before. Perhaps that also means that the display can be connected to the discrete GPU.
Hopefully Apple has since QS is definitely awesome. However, this could have been achieved with H67 as well since it supports the IGP as well so the main point of using Z68 still seems to be the SRT.