HD Buffer Size

  • Thread starter Thread starter Bob Simon
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Bob Simon

Maxtor and Seagate both have 120GB 7200rpm EIDE drives with either 2MB
or 8MB buffer. (ST3120023A vs ST3120026A and 6Y120L0 vs 6Y120P0.)

Am I likely to notice a real-world performance difference from the
larger buffer with a single HD (plus CD and CR-RW) connected to an
ATA66 controller in a machine running Windows XP?
 
Maxtor and Seagate both have 120GB 7200rpm EIDE drives with either 2MB
or 8MB buffer. (ST3120023A vs ST3120026A and 6Y120L0 vs 6Y120P0.)
Click to expand...
Am I likely to notice a real-world performance difference from the
larger buffer with a single HD (plus CD and CR-RW) connected to
an ATA66 controller in a machine running Windows XP?
Click to expand...

Nope. And not in a more modern PC either.
 
Bob said:
Maxtor and Seagate both have 120GB 7200rpm EIDE drives with either 2MB
or 8MB buffer. (ST3120023A vs ST3120026A and 6Y120L0 vs 6Y120P0.)

Am I likely to notice a real-world performance difference from the
larger buffer with a single HD (plus CD and CR-RW) connected to an
ATA66 controller in a machine running Windows XP?
Click to expand...

If you're working with smallish files, you *may* notice a difference.
Probably not.

However, the Seagate is infinitely more reliable than the Maxtor, so
that would be the better bet.


Odie
 
Can you explain in a simple way, how is the buffer used for reading data
from the drive? I am guessing that when WRITING to the drive the buffer can
accept data as if it were written to the disk, and make small file writes
seem faster than they really are. But for reading, does the buffer
significantly help out?

THANKS!
--Dan
 
Maxtor and Seagate both have 120GB 7200rpm EIDE drives with either 2MB
or 8MB buffer. (ST3120023A vs ST3120026A and 6Y120L0 vs 6Y120P0.)

Am I likely to notice a real-world performance difference from the
larger buffer with a single HD (plus CD and CR-RW) connected to an
ATA66 controller in a machine running Windows XP?
Bob Simon
Click to expand...

Well, buffer size is not the only difference.
For example comparing Seagate 26A with 23A:
- 8MB buffer vs. 2MB
- 3 heads vs. 4
- 85.4MBytes/sec internal tranfer rate vs. 570Mbits/sec
- 58MBytes/sec sustained transfer rate vs. 27-44MBytes/sec
- 8.5/8.5/9.5msec seek/read/write access time vs. 9.4/9.4/10.5msec

I would choose 26A, but real-world performance differences might be
relatively small.
 
Can you explain in a simple way, how is the buffer used for reading data from
the drive? I am guessing that when WRITING to the drive the buffer can accept
data as if it were written to the disk, and make small file writes seem faster
than they really are. But for reading, does the buffer significantly help
out?
Click to expand...

In theory at least the drive can read more than was asked for from
the platters on a read request, hoping that the next read request
will be for what it read from the platters without being asked for.
Then it can return the data for the second read request from the
buffer instead of having to wait for the platters to rotate the data
under the heads for the second request.

In practice its isnt that easy for the drive to work out what
might be requested next, so its all rather theoretical, particularly
with modern OSs which have multiple tasks reading much of the time.
 
Well, buffer size is not the only difference.
For example comparing Seagate 26A with 23A:
- 8MB buffer vs. 2MB
- 3 heads vs. 4
- 85.4MBytes/sec internal tranfer rate vs. 570Mbits/sec
- 58MBytes/sec sustained transfer rate vs. 27-44MBytes/sec
- 8.5/8.5/9.5msec seek/read/write access time vs. 9.4/9.4/10.5msec

I would choose 26A, but real-world performance differences might be
relatively small.
Click to expand...
Thanks. I also noticed those other differences when I compared the
spec sheets but I (mistakenly) thought that buffer size might be the
most significant difference since that's listed in the PriceWatch ads

I guess I should have asked which parameter is the most significant
indicator or real-world performance. Would that be sustained transfer
rate?
 
Well, buffer size is not the only difference.
Thanks. I also noticed those other differences when I compared the
spec sheets but I (mistakenly) thought that buffer size might be the
most significant difference since that's listed in the PriceWatch ads

I guess I should have asked which parameter is the most significant
indicator or real-world performance. Would that be sustained transfer
rate?
Click to expand...

That would depend on real-world application, for a single user,
multimedia app - sustained transfer rate might be the most important
factor. For a multiuser database, that might be a maximum IO/sec.
In both cases 26A is better than 23A.
 
Bob Simon said:
Thanks. I also noticed those other differences when I compared the
spec sheets but I (mistakenly) thought that buffer size might be the
most significant difference since that's listed in the PriceWatch ads

I guess I should have asked which parameter is the most significant
indicator or real-world performance. Would that be sustained transfer
rate?
Click to expand...

Nope, the rate the sectors move under the heads.

Unfortunately that isnt a tidy number usually listed on the manufacturer's web
site.
 
Nope, the rate the sectors move under the heads.

Unfortunately that isnt a tidy number usually listed on the manufacturer's web
site.
Click to expand...
Wouldn't that imply that for a given rpm, larger drives will give
better performance? I hope so because I just ordered an ST3200822A
from Fry. With the $50 rebate (that ends today) it was less than the
ST3120026A.

(BTW, I have read about problems with Seagate rebate fullfillment but
I am patient and persistant so I expect that this will work out ok for
me in 2 or 3 months.)
 
Wouldn't that imply that for a given rpm,
larger drives will give better performance?
Click to expand...

Its more complicated than that because the large drive may
have more platters and/or more tracks per platter surface.
I hope so because I just ordered an ST3200822A from Fry. With
the $50 rebate (that ends today) it was less than the ST3120026A.
Click to expand...

The ST3200822A would be marginally faster, its got 50GB
per surface compared with 40GB for the ST3120026A.
(BTW, I have read about problems with Seagate rebate
fullfillment but I am patient and persistant so I expect that
this will work out ok for me in 2 or 3 months.)
Click to expand...

Yeah, with an operation of that size, it should be possible to
do them over on the rebate if you follow the detail required
precisely and keep demanding your rebate if it doesnt show up.
 
Derek Baker said:
I do believe they got those results in their benchmarks: I trust
storagereview.com.
http://www.storagereview.com/php/be...&numDrives=1&devID_0=218&devID_1=219&devCnt=2
Click to expand...

Sure, but what matters is how relevant the
benchmark is to the real world use of the drives.
I agree about the subjective performance though: I didn't notice that my
ATA-100 drive with a 40MB/sec average transfer rate was running at 15MB/sec
recently.
Click to expand...

Yeah, thats what I meant.
 
Previously Bob Simon said:
Maxtor and Seagate both have 120GB 7200rpm EIDE drives with either 2MB
or 8MB buffer. (ST3120023A vs ST3120026A and 6Y120L0 vs 6Y120P0.)
Click to expand...
Am I likely to notice a real-world performance difference from the
larger buffer with a single HD (plus CD and CR-RW) connected to an
ATA66 controller in a machine running Windows XP?
Click to expand...

No. But you will notice the warranty difference on the Maxtor
drives: 3 years for the 8MB model, 1 year for the other one.

Arno
 
http://faq.storagereview.com/tiki-index.php?page=BufferSizes
I do believe they got those results in their benchmarks: I trust
storagereview.com.
http://www.storagereview.com/php/be...&numDrives=1&devID_0=218&devID_1=219&devCnt=2

I agree about the subjective performance though: I didn't notice that my
ATA-100 drive with a 40MB/sec average transfer rate was running at 15MB/sec
recently.
Click to expand...

It all depends on what applications are being used as well. Would someone
using the box for websurfing, email and the occasional Word document notice
a difference? Probably not. Would someone using disk intensive video apps
that routinely use 50-100 gig files notice a difference? You bet.
 
Bob said:
Maxtor and Seagate both have 120GB 7200rpm EIDE drives with either 2MB
or 8MB buffer. (ST3120023A vs ST3120026A and 6Y120L0 vs 6Y120P0.)

Am I likely to notice a real-world performance difference from the
larger buffer with a single HD (plus CD and CR-RW) connected to an
ATA66 controller in a machine running Windows XP?
Click to expand...

Gosh, you're the first person to ever ask that question!

Ever hear of Google, moron?
 
Chuck U. Farley said:
It all depends on what applications are being used as well. Would someone
using the box for websurfing, email and the occasional Word document notice
a difference? Probably not. Would someone using disk intensive video apps
that routinely use 50-100 gig files notice a difference? You bet.
Click to expand...

I doubt it on that last.
 
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