having to help Rev (was: Re: Memory Leak on export png????)

Kay C Lan lan.kc.macmail at gmail.com
Sat Mar 24 04:14:34 EDT 2007


As there has been talk of 'thorough testing' and in light of the recent
posts trying to steer this thread into a different direction I thought I'd
share my own recent tests. Not really Rev related, but as I'm sure everyone
here does regular and thorough backups this may be of interest to one or two
others. Also I'm waiting for Rev to download gm-4:-)

For a while I've had this impression that my FW400 2.5" 5400rpm portable HD
backed up faster than my USB2 3.5" 7200rpm External HD so I finally got
around to actually sitting down and timing it and was extremely surprised.

My test was 'real world' but not fair in that I 'Carbon Copy Cloned' one
partition on my MacBook Pro to the FW400 2.5" and a different partition to
the USB2 3.5" and used Activity Monitor to record the time at 1GB write
intervals plus total time vs total GBs written. Of course there is a host of
reasons why one partition may backup faster than another, but the results
were so disparate (in favour of FW400) that I decided I needed a proper
test.

So using Drive Genius' 'Benchmark' facility I set about testing my 3.5"
External HD which has both FW400 and USB2 connections. I've been using the
USB2 connection because the advertised speed is suppose to be 120% that of
FW400.

Sustained Read Speeds
measures how many times single-block reads can be performed in one second.
This test is affected by read caching (the larger the read cache, the faster
the performance).

Data    FW400        USB2        FW/USB
32K        32.653 MB/s    10.390 MB/s    314%
64K        36.364 MB/s    15.534 MB/s    234%
128K    38.095 MB/s    20.779 MB/s    183%
256K    39.024 MB/s    21.477 MB/s    182%
0.5M    39.506 MB/s    21.333 MB/s    185%
1M        40.000 MB/s    21.192 MB/s    189%
2M        40.000 MB/s    20.915 MB/s    191%
4M        39.506 MB/s    21.769 MB/s    181%
8M        39.506 MB/s    21.769 MB/s    181%
16M        39.025 MB/s    22.535 MB/s    173%

Sustained Write Speeds
measures how many times single-block writes can be performed in 1 second.
This test is affected by write caching (the larger the write cache, the
faster the performance).

32K        17.978 MB/s    7.805 MB/s    230%
64K        30.769 MB/s    12.500 MB/s    246%
128K    32.323 MB/s    17.297 MB/s    187%
0.5M    33.333 MB/s    17.204 MB/s    194%
1M        33.684 MB/s    17.297 MB/s    195%
2M        33.684 MB/s    17.391 MB/s    194%
4M        33.684 MB/s    17.204 MB/s    196%
8M        33.684 MB/s    17.680 MB/s    191%
16M        33.684 MB/s    17.204 MB/s    196%

Random Read
measures drive performance for reads of blocks of data from 2 kilobytes to
16 megabytes.
For small block sizes, seek time and rotational latency are weighted more
heavily. For large block sizes, the transfer rate is weighted more heavily.

32K        5.624 MB/s    4.552 MB/s    124%
64K        9.143 MB/s    8.020 MB/s    114%
128K    15.920 MB/s    12.749 MB/s    125%
256K    22.857 MB/s    15.610 MB/s    146%
0.5M    26.891 MB/s    17.978 MB/s    150%
1M        32.653 MB/s    19.632 MB/s    166%
2M        35.165 MB/s    20.915 MB/s    168%
4M        37.647 MB/s    21.333 MB/s    176%
8M        39.024 MB/s    21.333 MB/s    183%
16M        39.024 MB/s    21.192 MB/s    184%

Random Write
measures drive performance for writes of blocks of data from 2 kilobytes to
16 megabytes.
For small block sizes, seek time and rotational latency are weighted more
heavily. For large block sizes, the transfer rate is weighted more heavily.

32K        10.561 MB/s    5.964 MB/s    177%
64K        15.842 MB/s    9.846 MB/s    161%
128K    23.358 MB/s    15.385 MB/s    152%
256K    30.476 MB/s    16.410 MB/s    186%
0.5M    32.990 MB/s    16.842 MB/s    196%
1M        33.684 MB/s    17.021 MB/s    198%
2M        33.684 MB/s    17.021 MB/s    198%
4M        33.684 MB/s    16.754 MB/s    201%
8M        33.684 MB/s    17.297 MB/s    195%
16M        33.684 MB/s    17.486 MB/s    193%

The Drive Genius guff about each of the tests and what effects the speed is
irrelevant in my case as the HD is the same, the only 'variables' are the
bus controllers, the bus and the wire between them.

Interestingly, although theoretically USB2 is suppose to be 120% FW400 my
results are the exact opposite, FW400 only once fell below 120% the speed of
USB2 and consistently ran at close to 200%.

Guess I'll be disconnecting the USB2 and going with FW400:-)

I'm assuming that my 3.5" HD must have a cheap and 'speed challenged' USB2
controller because if every other USB2 drive produced these kind of results
I'm sure there'd be an uproar. I just wish I'd gone with my 'gut feeling'
earlier and gone with FW400, I'd have saved myself half the time waiting for
backups to complete:-(



More information about the use-livecode mailing list