HD 40 GB RPM 5400 or HD 80 GB RPM 4200?

IBM lists two laptops with different Hard Drives. Both are ATA-100 (Enhanced
IDE) with identical average seek time (12 ms), Average latency (7.1 ms),
Cache size (2MB) and Sustained data transfer rates (30/16 MBps).



One is 40 GB with Platter RPM of 5400, the other one is 80 GB with Platter
RPM of 4200. Is the difference of speed important enough to choose the
smaller HD?

Why not get one custom made with a 7200 rpm hard drive?

Gilbert wrote:

IBM lists two laptops with different Hard Drives. Both are ATA-100 (Enhanced
IDE) with identical average seek time (12 ms), Average latency (7.1 ms),
Cache size (2MB) and Sustained data transfer rates (30/16 MBps).

One is 40 GB with Platter RPM of 5400, the other one is 80 GB with Platter
RPM of 4200. Is the difference of speed important enough to choose the
smaller HD?

"JK" wrote in message
...
Why not get one custom made with a 7200 rpm hard drive?


That is what I would like to do but IBM (Canada) does not custom configure
Thinkpads.

Why not get one custom made with a 7200 rpm hard drive?



That is what I would like to do but IBM (Canada) does not custom configure
Thinkpads.

Most manufacturers don't put a 7200 rpm drive as an option in laptops -
in addition to running faster they run hotter.

"David Besack" wrote in message
...

Most manufacturers don't put a 7200 rpm drive as an option in laptops -
in addition to running faster they run hotter.

I agree that faster HD run hotter. However, in its most expensive ThinkPad
T42p, IBM offers a 60GB 7200rpm HD and a ATI Mobility FireGL T2 128 MB. It
costs double the T42 I am considering. I guess for someone with money to
burn nothing is too hot! :-)

Gilbert wrote:

IBM lists two laptops with different Hard Drives. Both are ATA-100 (Enhanced
IDE) with identical average seek time (12 ms), Average latency (7.1 ms),
Cache size (2MB) and Sustained data transfer rates (30/16 MBps).



One is 40 GB with Platter RPM of 5400, the other one is 80 GB with Platter
RPM of 4200. Is the difference of speed important enough to choose the
smaller HD?


I'd call their tech support and ask about the real specs because average
latency IS the rotational speed expressed in a different format, so it
can't be the same for the two. Which leads me to think they've simply put
the 4200 RPM specs up for both.

Average latency is half the rotational period: (1/(7.1ms x 2))*60 secs/min
= 4225 RPM. The 'precise' number (to 4 decimals) for a 4200 RPM drive would
be 7.1423ms. The 7.1 spec is rounded off and that's why it comes to 4225
when reverse calculated.

Average latency for a 5400 RPM drive should be 5.555...ms. STR and seek
times are more difficult to guess because the drive geometry may be different.

"David Maynard" wrote in message
...
Gilbert wrote:
IBM lists two laptops with different Hard Drives. Both are ATA-100
(Enhanced
IDE) with identical average seek time (12 ms), Average latency (7.1 ms),
Cache size (2MB) and Sustained data transfer rates (30/16 MBps).
One is 40 GB with Platter RPM of 5400, the other one is 80 GB with
Platter
RPM of 4200. Is the difference of speed important enough to choose the
smaller HD?


I'd call their tech support and ask about the real specs because average
latency IS the rotational speed expressed in a different format, so it
can't be the same for the two. Which leads me to think they've simply put
the 4200 RPM specs up for both.

You are right David; even though I am not an expert on HD, my logic told me
that the specs for a 5400 RPM should be different from those of a 4200 RPM.
I called IBM support and was told that the T42 comes with a 5400 RPM HD and
that the listed specs might be wrong, although they could not verify that.
IBM has hundreds of Thinkpad configurations; it is absurd. And it so
confusing that even they get confused.

On Tue, 24 Aug 2004 00:40:30 GMT, "Gilbert" wrote:

IBM lists two laptops with different Hard Drives. Both are ATA-100 (Enhanced
IDE) with identical average seek time (12 ms), Average latency (7.1 ms),
Cache size (2MB) and Sustained data transfer rates (30/16 MBps).



One is 40 GB with Platter RPM of 5400, the other one is 80 GB with Platter
RPM of 4200. Is the difference of speed important enough to choose the
smaller HD?



Wow, even 5400 RPM seems a bit slow and obsolete these days. I am
surprised to see the same seek time for both drives. I probably
would not select an IBM HD, after what happened a few years ago.

Yes.

--
DaveW



"Gilbert" wrote in message
gers.com...
IBM lists two laptops with different Hard Drives. Both are ATA-100
(Enhanced
IDE) with identical average seek time (12 ms), Average latency (7.1 ms),
Cache size (2MB) and Sustained data transfer rates (30/16 MBps).



One is 40 GB with Platter RPM of 5400, the other one is 80 GB with Platter
RPM of 4200. Is the difference of speed important enough to choose the
smaller HD?

To All: Thank you for your input. T42 it is. I have ordered it. But I will
have to wait a few weeks for delivery because IBM Canada does not have the
extra memory and the multiburner in stock. Unbelievable!