Our tests focused on
discovering whether the BP4 could both read all the data it could write;
& write all the data it could read. We ran the usual speed-tests;
though stressing analysis rather than numbers; we also examined DAE
performance in some detail.
tests run at least five times on two samples of the BP4 f/w 4.31]
meaningful impression of the character of a CD-device's read-performance -
the nature of the performance that hides behind all those dreary
benchmarking numbers - is tricky; we've combined several benchmarking utilities' results with the
same test-media into tolerably analytic - if approximate - speed-graphs:
Speed 1 [red] =
Instantaneous speed, normally averaged into:
Speed 2 [green] = the
standard CD-SPEED99 graph.
Speed 3 [yellow] =
Average speed to time through disk
together, these show the BP4's sequential-read-performance over 50 minutes
into a disk, &/or over 34x, changes in character as rpm-stepping
tries - & fails - to maintain a stable transfer-rate.
The lower reflectivity
of a CDRW - even an HSRW
[High-Speed] - flattens the rising transfer-rate slope enough that this
change fails to show over a full 650Mb disk-read:
. . . while a
simple CDSPEED99 graph from a sequential-speed test with a clean pressed
CD [MS Windows 9x distribution-media] shows the peak speed of 35x to be
reached at a similar point to CDR media in the read, followed by a plateau where the
transfer-rate is maintained by rpm control, then a noticeable drop-off
towards the periphery of this 68minute disk.
In combination; these
graphs show a high-rpm device - the rate at the start of reads was
14x-18.5x throughout our tests - of irregular performance beyond 50
minutes into CD/CDR media.
we gained was that the BP4 is based on the mechanism of [say] a genuine 12-32x CAV
reader revved a touch higher to allow a marketing-claim of 40x peak
read-speed - which rate it probably can touch, for a wavering instant, towards
the end of a brand-new, full, pressed CD.
We found the end
result of this revving-up to be a 14-34x P-CAV reader - & a remarkably
Sanyo [& Mirai's]
claims for the BP4's read-performance are equivocal: Sanyo's BP4 web-page
speaks of "40x CAV" - & of course the "16/10/40"
description must lead the buyer to assume that a genuine 40x is part of
the deal: in slightly smaller print in the specifications, the phrase:
"Data Transfer Rate: 12-32x CAV" gives a less misleading
A true 40x CAV reader
- the Plextor 40TSi - shows an averaged sequential-read test graph like
this [with the 650Mb CDR test-disk]:
The BP4, with the same
. . . . in both
cases the "average" - as a benchmarked number, is quite similar:
but it's clearly not the same character or quality of performance.
The BP4 has fine
average random-access performance for a burner - here tested &
measured at 116ms with CDVD - making it perfectly usable with game &
reference disks. Again it was noticeable how quiet the BP4 was, even under
severe mechanical stress.
It is worth noting our
tests for random-access speed produced better [lower] figures than the
130ms claimed by Sanyo - we obtained the above or closely similar results
with several media in many test-runs in two samples of the BP4.
The 40TSi's average
random-access with the above disk was 90ms - given the considerably lighter
head of a pure reader, the BP4's performance stands out as excellent.
quality, tested by Feurio on an audio-disk, was perfect:
Additional data gleaned from
CDSPEED99 reinforced our findings as to the
quality of the BP4 as a boot-CD device. This task requires quick
recognition during the boot that the inserted CD is, in fact, bootable.
The Plextor 40TSi is
grotesquely slow at this, taking 6 seconds or more & often failing to
recognise boot-sector information: the BP4 takes only 0.6 seconds, &
all tested media - including elderly CDRW's - reliably enough to make
multi-boot-CD experiments enjoyable.
time to open the [slightly flimsy-feeling] tray
after software or button commands was unusually long; the open/close
So . . . a 40x reader?
. . ahem [cough]: but then, so what?
After all, the
real-world read-tasks of a standalone burner are to extract digital audio
- from the usual collection of randomly-abused favourite CD's - & to
allow faithful backup copies of your expensive software distribution
But we think this hint
of a mechanism pushed that tiny bit too
far towards a "40x" marketing-claim sounds quite likely, &
gives a misleading impression of the BP4's
read-performance. For how this might effect the BP4's
performance at serious read-tasks . . .
. . . read on .
. . .