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SkyCapt's picture
Joined: 2017 Jan 11
Making USB2 faster, better

Three things are affecting the speed of USB2 systems :

.1 - Tiger OSX 10.4 drives USB2 significantly slower than Leopard OSX 10.5.8
.2 - USB3.0 "(camera) card readers" are faster than USB2 card readers, even when the bus is USB2
.3 - host controllers vary greatly speedwise depending on year of manufacture 2001-2008+

I have two Macs both USB2 but so different: PowerMac G4 (2003) and iMac 2007. The 2007 has mature USB2 native, per-port writes max 25.1 MB/s and reads max 38.3 in Leopard, but writes max 17.7 MB/s and reads max 25 MB/s in Tiger. For my PMG4 its native is USB1 slow speed, so for it I have PCI cards that implement USB2. I've tested 4 cards made from 2002 to 2008 and they're all different speed. Looks like USB2 was introduced on weak cards and cards were slowly bumped up speedwise until USB3 began in 2009. I have 4 different makes of card: ALI, VIA, Stratitec, Belkin. The fastest is my Stratitec, it reads 22 MB/s in Leopard, writes 21.1 MB/s in Leopard, reads 15.6 MB/s in Tiger, writes 15.1 MB/s in Tiger. The other/older PCI cards range at writing in Tiger from 10 MB/s to 13 MB/s, so I use only the Stratitec card. I'm using the speed test software "QuickBench" (found here in the apps) test #6 default settings. I'm using devices capable of maxing USB2, I've phased out the stuff which can't maxout my best USB2 busses.

There should be newer manufactured PCI cards that can go faster than any of the cards I have. Who's got a PowerMac G4 with USB2 speeds beating mine ?? What is its PCI card?


microSD storage and their "card readers" are incredible. It's a thumbdrive, in which the RAM chip and the interface chip are separable and independently able to be isolated, tested, swapped, even independently upgraded. microSD-only card readers occupy only one USB port while full SD card readers block the physical access to adjacent USB ports. USB3.0 card readers are significantly faster than USB2 rated card readers, even when the bus is USB2 not 3.0 - also some USB2 card readers can't be made to do booting the computer, while all the USB3 card readers I tested can do booting. Jaguar and Panther (10.3.5 was tested) cannot be booted from USB storage; Tiger and Leopard and OS9 and AHT can be booted via USB. USB3 card readers will handle the highest capacities, whereas some USB2 card readers are limited to sometimes 32GB or less. I have one very old USB2 device limited to 512MB capacity, it accepts larger SD cards without complaining and writes beyond 512MB without complaining but saved info ceases to exist after 512MB - frustrating. I'm hoping USB3 devices (card readers) will ALL be able to handle up to 2TB troublefree.

microSD storage is too small to print a label on, and there's overpriced and dysfunctional cases out there - but I found the perfect case for holding 14 or more microSD, and it cost one dollar. It's a clear plastic "pill organizer" with two weeks worth of sugarcube size compartments. The flat bottom is big enough to tape a printed directory label to it, or even better so the case isn't always being flipped over to read the directory, I made a flapless paper envelope to hold the directory card and it is this envelope which gets taped to the underside.


24bit's picture
Joined: 2010 Nov 19

Thanks for sharing your findings SkyCapt.
I did compare USB with Tiger, Leopard and Snow Leopard on my T60.
The USB stick and the USB port were always the same.
The USB hardware is this:


Product ID: 0x0024
Vendor ID: 0x8087 (Intel Corporation)
Version: 0.00
Speed: Up to 480Mb/sec
Location ID: 0x1a100000 / 1
Current Available (mA): 500
Current Required (mA): 0
Extra Operating Current (mA): 0
Built-In: Yes



Snow Leopard:

Looks like the USB stack was rewritten for Leopard, but not much was changed for 10.6.
480 Megabit per second looks like wishful thinking still. Smile

SkyCapt's picture
Joined: 2017 Jan 11

You got very slow write speed, so slow that the QuickBench test itself will be boring to use. You could trade up your flash nvram chip for a newer one and then write to it much faster.

Your (peak) read speeds look just like mine across Tiger and Leopard on my MDD-2003 : 15.6 MB/s Tiger, 22 MB/s Leopard. In all my life I've never gleaned that Leo does USB2 so much better than Tiger. Only now learned this, having gotten and started using the QuickBench. Perhaps Tiger (the better OS) can be injected with the USB driver(s) from Leopard to make Tiger equally fast.

480 Mb/s equals 60 MB/s as this happened when we all knew there are 8 bits in a byte, not fantasy 10 bits like how SATA began talking in the year 2006 when they rewrote "SATA 150 MB/s" as equalling "SATA 1.5 GB/s". Anyway...

My iMac late-2007/early-2008 reads USB2 (in Leopard) at peak 38.3 MB/s which is a healthy chunk, significantly more than 50% of, 60MB/s. Knowing that an individual USB2 cable can do that, means I should be able to get a PCI card for my MDD2003 which does the same.

38.3 MB/s not bad for a bus originally optimized for keyboard/mouse and mass-storage an afterthought. A weird effect of its architecture is how any/every bottleneck sends out a proportional speed reduction across all various configurations. See how your snail's pace write speed in Leopard becomes proportionally slower when you switch to Tiger. Any normal bus would retain the same low write speed while just clipping off the best read speed to a lower ceiling.

microSD cards now avail in 256GB size for under $175 (or 128GB for just $30). Wonder what the max capacity in that tiny package size is going to end up being.

24bit's picture
Joined: 2010 Nov 19

Absolutely, 38.8 GB/s read is probably as much as one can get with USB2.
The USB stick I tried is one of my worst, I know.
Picked it up for little cash at Media Markt or Saturn more than two years ago.
Its a Intenso Business Line stick, who knows what kind of business Intenso was aiming at?

Intenso Business Line:

Product ID: 0x6387
Vendor ID: 0x058f (Alcor Micro, Corp.)
Version: 1.05
Serial Number: 15042000000825
Speed: Up to 480Mb/sec
Manufacturer: Alcor Tech
Location ID: 0x1d120000 / 4
Current Available (mA): 500
Current Required (mA): 200
Extra Operating Current (mA): 0

The device was used for holding a few SD .ts video files for the small LCD TV in the kitchen.
To my surprise the device is still working, a few others are dead meanwhile.
We switched to Seagate STDR5000102/3 drives, another story. Smile
SMR was not the brightest idea ever for harddisks, when you want to write them more than once.