HDD RPM and Cache - How Important?

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Keith

I am looking to buy an external Firewire/USB2 to use as a backup device for
my PC and Laptop.

I have settled on the Maxtor OneTouch at the moment.

The 250GB model (http://tinyurl.com/62ykv) has an RPM of 7200 and an 8MB
cache.

The 300GB model (http://tinyurl.com/4kkvh) has an RPM of 5400 and a 1MB
cache.

The price difference is very small and I would rather go for the bigger one,
but not if it's going to be much slower.

What difference will the RPM and cache make to the transfer rate I get when
backing up over Firewire?

What MB/sec rate should I realistically expect to get from them?
 
I am looking to buy an external Firewire/USB2 to use as a backup device for
my PC and Laptop.

I have settled on the Maxtor OneTouch at the moment.

The 250GB model (http://tinyurl.com/62ykv) has an RPM of 7200 and an 8MB
cache.

The 300GB model (http://tinyurl.com/4kkvh) has an RPM of 5400 and a 1MB
cache.

The price difference is very small and I would rather go for the bigger one,
but not if it's going to be much slower.

What difference will the RPM and cache make to the transfer rate I get when
backing up over Firewire?

What MB/sec rate should I realistically expect to get from them?
Click to expand...

The firewire interface is the bottleneck, it won't make much
if any difference what the RPM or cache size is for this
type of use.

Expect in the neighborhood of 28MB/s read, 25MB/s write, +-
8MB/s but it could also depend on the firewire chips used at
both ends of the cable (the drive enclosure and the
motherboard/PCI-card) and other system factors to a lesser
degree. I have no data about that particular OneTouch
product but there is no reason to expect it will perform
atypically.
 
I am looking to buy an external Firewire/USB2 to use as a backup device for
my PC and Laptop.
Click to expand...
The 250GB model (http://tinyurl.com/62ykv) has an RPM of 7200 and an 8MB
cache.

The 300GB model (http://tinyurl.com/4kkvh) has an RPM of 5400 and a 1MB
cache.

The price difference is very small and I would rather go for the bigger one,
but not if it's going to be much slower.

What difference will the RPM and cache make to the transfer rate I get when
backing up over Firewire?
Click to expand...

The bottleneck is mechanics! get the SMALLER 7200rpm drive !!!! (it
also has few times bigger cache, which helps at transfer speeds too !!
(IMHO it is gonna be 30% approx faster than that 5400 rpm one)
 
Keith said:
I am looking to buy an external Firewire/USB2 to use as a backup device for
my PC and Laptop.

I have settled on the Maxtor OneTouch at the moment.

The 250GB model (http://tinyurl.com/62ykv) has an RPM of 7200 and an 8MB
cache.

The 300GB model (http://tinyurl.com/4kkvh) has an RPM of 5400 and a 1MB
cache.

The price difference is very small and I would rather go for the bigger one,
but not if it's going to be much slower.

What difference will the RPM and cache make to the transfer rate I get when
backing up over Firewire?

What MB/sec rate should I realistically expect to get from them?
Click to expand...

For backup go with the bigger. Backup rate depends on a number of issues
and often NOT the speed of the HD. Doing a copy of a 1GB file in about 30
seconds should be realizable and maybe faster using USB2.
 
Spajky said:
The bottleneck is mechanics! get the SMALLER 7200rpm drive !!!!
NO!

(it
also has few times bigger cache, which helps at transfer speeds too !!
NO!

(IMHO it is gonna be 30% approx faster than that 5400 rpm one)
Click to expand...

Just NO!
 
The 5400 rpm model with only 1 MB of cache will be MUCH slower. I wouldn't
recommend going with it.
 
DaveW said:
The 5400 rpm model with only 1 MB of cache will be MUCH slower. I wouldn't
recommend going with it.
Click to expand...

The OP said:
"I am looking to buy an external Firewire/USB2 to use as a backup device for
my PC and Laptop."

Neither the 5400RPM nor the 1MB cache will make it "much slower" for the
intended use.

I checked the Maxtor website and it appears that the 300GB 5400RPM model is
in fact 2MB cache...ah the URL below also confirms that so the OP mis-stated
1MB.

A little research shows that the 5400RPM drive inside is almost certainly a
Maxline II:
http://www.maxtor.com/_files/maxtor/en_us/documentation/data_sheets/maxline_data_sheet.pdf

Looking at that one sees:
"Max sustained data transfer rate up to 59MB/sec"
That is faster than either USB2 or Firewire.

In non-seek limited operation, like a backup tends to be, the 300GB
5400RPM model will not be slower than the 7200 RPM model.
 
"Max sustained data transfer rate up to 59MB/sec"
That is faster than either USB2 or Firewire.
Click to expand...

See that marketing blurb? : ... up to ...?
that practically almost never occurs like same with Lan, Firewire,
Usb2 or WiFi equipment; actual real life numbers are much slower &
firewire external stuff is faster than USB2 even it last one has
higher bandwith IMHO!

same is with copying a huge zipped file between two HDs on
different IDE channels, the actual speed mesured with stop watch &
calculated later would show much lower practical values than
manufacturers would like us to believe!

Yes, if the time of backUp operation is not important, I would also
take a larger even if IMHO slower drive if the price doesnt matter
too!
 
I'd buy bigger one, too.
One more important thing you forgot to tell us is do they have same
number of plates?
Bigger HDDs with same RPM must be faster.
Anyway, other things like software are also important, IMO at least.
 
I just ordered the 300GB 2MB Cache 5400RPM model

I'll let everyone know ho wit performs when it arrives.
 
Keith said:
I just ordered the 300GB 2MB Cache 5400RPM model

I'll let everyone know ho wit performs when it arrives.
Click to expand...

I bought a computer, P-4 2.8Ghz 180 GB HDD 7200, don't know cache, 512 MB
RAM. Computer was about to blow up; store replaced it with P-4 3.07, 250 GB
HDD, 1 GB RAM. Oh, did I mention that the drive was 5400? To make a long
story short, the new one was pokey compared to the first one.

HankG
 
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