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GodWhomIsMike
Oct 7, 2007, 12:38 PM
What are the cache sizes of the hard drives in the new iMac?

320GB Serial ATA Drive? 8MB or 16MB?
500GB Serial ATA Drive? 8MB or 16MB?
750GB Serial ATA Drive? 8MB or 16MB?
1TB Serial ATA Drive? 16MB or 32MB?


FatSweatyBlldog
Oct 7, 2007, 02:59 PM
Depends on the type/manufacturer of drive Apple uses for that lot of computers.

To date, the caches have been reported as such, in the order of models you list below:

8MB
16MB
16MB
32MB
RevToTheRedline
Oct 7, 2007, 03:19 PM
The 500GB is a Western Digital S-ATA 2 with 16MB cache. The 1TB drive is most certainly a 32MB cache drive cause I don't think any companies make them with less than 32MB cache.

The 320GB is probably an 8MB.
HLdan
Oct 7, 2007, 04:20 PM
What does cache do in a hard drive?
RevToTheRedline
Oct 7, 2007, 04:24 PM
What does cache do in a hard drive?

It's basically ram for your hard drive, it stores frequently used things for much faster access, the burst speed from the cache of the 500GB drive is 180MB/s thanks to the S-ATA 2 connection and the 16MB of cache.

The more the better, this is why higher end CPU's also have more cache, for example the Core 2 Duo has 4MB, part of the reason its so much faster than CPU's of the past like AMD Athlons which only had 256KB.

Here is some more info on it if you wanna do some reading. http://en.wikipedia.org/wiki/Cache
mklos
Oct 7, 2007, 05:26 PM
I have a brand new 24" iMac and it has 8MB of cache in it. Its a 320GB Western Digital SATAII 7200RPM hard drive.
Leon Kowalski
Oct 8, 2007, 12:25 AM
Depends on the type/manufacturer of drive Apple uses for that lot of computers.
Yep, the only way to know for sure is to find the drive's model number (About This Mac > More Info > Serial-ATA) and look it up on the manufacturer's web site.

LK
gormond
Oct 8, 2007, 04:13 AM
Yep, the only way to know for sure is to find the drive's model number (About This Mac > More Info > Serial-ATA) and look it up on the manufacturer's web site.

LK

I had a look at the 24" iMacs in my local shop and they used "WD3200AAJS" which has 8MB Cache.
Leon Kowalski
Oct 8, 2007, 04:27 AM
I had a look at the 24" iMacs in my local shop and they used "WD3200AAJS" which has 8MB Cache.
Yep, that's what mine has -- but you can't depend on it, in general. The next batch from China could have a different drive from a different manufacturer. Apple's iMac specs don't make any promises about the size of the disk cache.

LK
gormond
Oct 8, 2007, 04:57 AM
Yep, that's what mine has -- but you can't depend on it, in general. The next batch from China could have a different drive from a different manufacturer. Apple's iMac specs don't make any promises about the size of the disk cache.

LK

Indeed but in general you have small chance of getting 16MB cache in a 320GB drive but a good chance with 500 and 750, and as mentioned above the 1TB drives only come with 32MB cache.