Choosing an External HD?

go with seagate dude the badwidht of data bus and memory bus is seen by ur board transfer rate

and for hdd it is known by it's R/W speed i.e. rpm

Do NOT worry about SATA III (6 Gb/s). Few hard drives actually exceed the speed of original SATA, and NONE will match the new SATA 6Gb/s max speed. That will be used almost exclusively by Solid State "Drives" with no mechanical parts. SATA II is all you'll ever need in a hard drive for the near future.

In general, be careful comparing numbers - as you have seen, some look vastly different and seem to make no sense. The major "mismatch" is between peak (or max) burst transfer rate for data, and the average rate over a long test of varied data and file types. (Also watch for Mb/s versus MB/s!) USB2 has a max burst data transfer rate of 480 Mb/s, often quoted instead as 60 MB/s, assuming a byte is only 8 bits. The new USB3 is ten times faster at max. In actual tests of performance over your kind of task - long sessions of copying a mixture of file types from one drive to another - typical average data transfer rates for USB2 are around 30 MB/s, maybe up to 40. Look at reviews and tests reports here on Tom's and elsewhere for such real-world data.

In selecting an external drive you typically have about 4 interface options between computer and external case. In rough order of average transfer speed, they are: USB2, Firewire 400 (aka IEEE 1394a), eSATA, and Firewire 800 (aka IEEE 1394b). Firewire 400 and eSATA tend to be similar in speed, around 50 to 80 GB/s depending on tests and how recent the equipment is (newer stuff seems to perform better, and lately eSATA is faster than Firewire 400). Of course, in order to use any of these you need to have the matching port on your computer. USB2 is almost everywhere, so if you plan to carry your external drive to other places as a means of transporting data, this is a good choice. Firewire 400 is becoming more common, and so is eSATA. One advantage eSATA has is that, inside the external case, there is basically no real data processing between the eSATA system and the SATAII drive inside, so that eliminates any delays of a translation interface. Firewire 800 is much less common in PC systems, more common in Macs. It is VERY common to find an external drive with more than one interface system, to be used one at a time. For example, mine has both USB2 and eSATA; I use the eSATA interface because my mobo has that port built in and it is faster.

One option for you also is to assemble you own by buying separately a case and a hard drive. This way you may save money and get exactly the HDD unit you want. But you must do the assembly (not hard at all) and this form rarely comes with free software for backups and the like, whereas you may get that with a complete external HDD unit. IF you do that, make sure the case you buy has both the type(s) of interface(s) to the computer that you want, AND the internal system to connect to the drive you choose (IDE is less common now, SATA II a better choice).

7200 rpm drives are faster than 5400 rpm drives, although if you are using only the USB2 interface I'm not sure the difference will be so noticeable. A larger cache size is useful especially if your use pattern tends to be accessing long files in sequence, as opposed to randomly grabbing little files all over the drive. In fact, for your major uses - backups, and large video files - that is exactly what you will do most of. So forget 8 MB cache, go for 32 if you can, and no less than 16. In fact, some of the new WD Green units have a 64 MB cache to help offset the slightly slower performance of the 5400 rpm speed. But they really are a good choice for backup units where absolutely top speed is not essential and you can take advantage of their lower power consumption (and heat generation inside the external case).

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What an deep explanation well my mouth started 2 yourn...

YOu can also say it in simple words sata 3.0 is capable transfer data rate maximum than other sata 2.0


From where did u copy pasted dear !!!!!!!!!!!!!!!!

wow, thanks for all your great input and information.

have you heard anything about Caviler or Fantom Drives products?

No, I have not, which may only prove that I have not been looking at that field recently. I assembled my external drive a few years ago with a Seagate 500 GB SATA II unit in an AZIO case. Hopefully others here can comment from recent experience.

thanks for being so helpful ill keep looking around for some recent reviews. hopefully someone, somewhere will know about these two brands

It is usually advisable to actually make sense when posting an answer on the forum.