Which of these hard drives should I get?

Ardent · 21-01-2005 1:40pm #1

One has a 2 MB buffer
http://www.elara.ie/products/detailsfullat.asp?productcode=ECS987684&productID=

while the other has a 16 MB buffer
http://www.komplett.ie/k/ki.asp?sku=303454&cks=PLC

The seek times are similar. Is it a no-brainer, what effect does a larger buffer have?

Khannie · 21-01-2005 2:06pm

A larger buffer helps with stuff that has been read from disk recently (not sure if the drives have pre-emptive read ahead into buffer type algorithms....if they do, that's another way it would help...by caching stuff into memory that's likely to be requested from disk).

On a usb disk I would imagine that you're unlikely to notice the difference (since the main bottleneck will be the USB bus).

The elara one isn't coming up for me, but if it's cheaper, I'd get that (personally).

Peteee · 21-01-2005 2:17pm

Khannie wrote:

On a usb disk I would imagine that you're unlikely to notice the difference (since the main bottleneck will be the USB bus).

HUH???

A usb 2.0 interface is in the region of 480 mb/sec, which is far faster then a Hard drive can provide (provided the data is not in the HD buffer)

I'd say definetly get the 16 meg buffer one, its only 7 euros more

Ciaran500 · 21-01-2005 2:22pm

Correct me if I'm wrong but USB2.0 can provide 480mb/s or 60MB/s. IDE can in theory do 800mb/s or 100MB/s.

bigfeller · 21-01-2005 2:32pm

Why not go for something like:
http://www.komplett.ie/k/ki.asp?sku=123721&cks=PRL
and
http://www.komplett.ie/k/ki.asp?sku=117527&cks=PRL

bigfeller · 21-01-2005 2:33pm

or this one with 16mb
http://www.komplett.ie/k/ki.asp?sku=302611&cks=PRL

Peteee · 21-01-2005 2:37pm

Ciaran500 wrote:

Correct me if I'm wrong but USB2.0 can provide 480mb/s or 60MB/s. IDE can in theory do 800mb/s or 100MB/s.

Thats the bus though, hard drives cant keep up with the bus, so I dont think a hard drive could max out a usb 2.0 connection

Ciaran500 · 21-01-2005 2:45pm

2nd generation SATA drives are averaging closer to 50MB/s with peaks of around 90MB/s

Khannie · 21-01-2005 3:25pm

Must admit that I was surprised at how low you quote throughput being from the drives. I expected that since SATA 150 drives are all the rage that they must be outstripping their PATA 133 counterparts (and therefore knocking the crap out of a 480mb bus).

In theory, SATA bus = 150MB * 8 (to convert to bits), so 1200mb.

Ardent · 21-01-2005 3:57pm

bigfeller wrote:

Why not go for something like:
http://www.komplett.ie/k/ki.asp?sku=123721&cks=PRL
and
http://www.komplett.ie/k/ki.asp?sku=117527&cks=PRL

That's brilliant! I didn't know you could do that - an enclosure for a HDD. Will it work just like an external hard drive?

po0k · 21-01-2005 5:06pm

Ciaran500 wrote:

Correct me if I'm wrong but USB2.0 can provide 480mb/s or 60MB/s. IDE can in theory do 800mb/s or 100MB/s.

The burst-speed from a hard-drive is usually around 50MByte/sec, give or take 5MBps.
USB2.0 has a bit of overhead too.
To be honest, it makes sod-all difference. You aren't going to notice the difference.

SATA, PATA speeds are for the channel.
Most of the bandwidth in SATA isn't used.
PATA is spread between both devices, but there are still losses due to switching between master and slave.

There's a reason SCSI and FC-AL drives are used where I/O is critical.

Which of these hard drives should I get?

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