How Cache in HDD effect my life?

[SmallGuy]

Hi
I see a lot of information around i see like Maxtor, IBM, WDC have cache 2 MB against Seagate Baracuda ATA, Quantum have only 512 KB . I want to know that how cache in HDD effect us when we capture and edit avi in Adobe Premiere ?

[This_Idiot]

The answer is "very little".

The figure you are looking for is the sustained read/write rate ignoring on-disk cacheing. If you are capturing small clips (ie less than the cache size) then on-disk cache may help, but on longer captures it makes no difference.

[Marijn]

Hi,

I agree with Idiot. For NLE it is indeed the sustained datarate that you are looking for. So the cachesize doesn't matter.

Even for other applications the size of the HDD cache isn't that important. Over at www.storagereview.com they tested two Maxtor drives (5120 series), both with different cache sizes. An earlier version of this drive carried 512kB, while the later version carried 2MB.

The results came to most of us as an surprise, since there was hardly an improvement. On some of the benchemarks, the 512kB scored even better!

So skip those figures, and you may find some benchmarks over at that site. That should give you more reallife information.

Succes,

Marijn

[Grigory]

Hi,
The answer is correct, but...

I have my own experience with 512 and 256 K HHD's and RR_G. Although the one with less cache was faster, its operation with RR_G was less reliable. A long discussion on this forum one year ago did not gave me an explanation.
Recently, I found another article, in Russian, where the author said that IBM 2 M cahe drive was better with Miro DC30 (same compression chip) than my old good Seagate of 512K.
This is again a strange evidence, because the drive itself COULD write systained uncompressed video stream at 6-8 MB/sec, but failed with 20% dropped frames with MJPEG data from MIRO.
I got similar behaviour with my two drives - both were fast enough to work with RR_G, but the unit with bigger cache had better performance with MJPEG data.

Conclusion: bigger cache size may be better for RR_G, provided other parameters are the same.
Sorry, I have no technical explanation confirmed by Matrox.
My idea was and is that MJPEG data stream is not perfectly uniform in time, which makes bigger drive cache, working as smoothing buffer, not completely useless.

Grigory.