USB2 Speeds

  AlanHo 23:15 06 Aug 2007

My computer has 4 USB2 sockets on the motherboard (at the rear of the tower) and two sockets at the front of the tower which are connected to an internal socket on the motherboard. I added 4 more USB2 sockets by fitting a USB2 PCI card into a spare slot in the tower to replace a Belkin USB2 powered hub.

I use an external USB2 SATA hard drive to take Acronis back-ups and have just discovered that the time taken varies considerably dependent upon which USB2 socket the drive is plugged into.

For example, To take a full disk image of my C: and D: drives (Acronis file size 47.7 GB) onto the external hard disk using Acronis 10 on my Vista computer takes the following times :-

Connected to a motherboard socket......49 minutes

Connected to the Belkin powered hub....58 minutes (I reconnected it - via a motherboard USB2 socket - for comparison purposes)

Connected to one of the front sockets..117 minutes

Connected to a socket on the PCI card......Acronis advised it will take 3 hours - I therefore cancelled the test.

There is clearly a huge difference between the various USB2 connections - but why?

(Be assured that the PCI card is a USB2 model)

  Stuartli 23:42 06 Aug 2007

Have you checked from Device Manager>USB Controllers that you have the word Enhanced listed in at least one of the USB Controllers?

  AlanHo 08:11 07 Aug 2007

The entries in Device manager under Universal Serial Bus Controller are :-

Generic USB Hub
Standard enhanced PCI to USB host controller
Standard enhanced PCI to USB host controller
Standard universal PCI to USB host controller
Standard universal PCI to USB host controller
Standard universal PCI to USB host controller
Standard universal PCI to USB host controller
Standard universal PCI to USB host controller
Uli PCI to USB open host controller
Uli PCI to USB open host controller
Uli PCI to USB open host controller
Uli USB 2.0 enhanced host controller
USB Mass storage device (appears 3 times)
USB printing support
USB root hub (appears 11 times)

  Stuartli 08:35 07 Aug 2007

That list appears fine - have you checked the PCI USB2.0 card is firmly seated?

  AlanHo 08:59 07 Aug 2007

Yes, card is well seated - I even tried another slot.

I have done some google browsing and have found a few references to people having similar problems. One claims that he solved the problem by swapping His VIA chipset card for one with an NEC chipset.

Just after shouting Eureka - I found that my card has an NEC chipset - so that is not a solution for me.

Thanks for your interest stuartli

  Stuartli 09:05 07 Aug 2007

Try updating the motherboard drivers to the latest version from the manufacturer's website.

Also see:

click here

as you haven't stated your operating system.

  AlanHo 10:14 07 Aug 2007


Antec Sonata Ultra Quiet ATX Midi Tower Case

Antec 380W TP

MSI MS 7235 Rev 1.1 266 MHz 775 socket
BIOS Phoenix 6.00 PG 18.08.06
On board 8 channel Realtek audio
On board Realtek PCI LAN ethernet connection
4 USB2 ports
1 PS/2 mouse port
1 PS/2 keyboard port
1 serial port (COM 1)
1 parallel port
1 LAN jack (10/100/1000)
6 flexible audio jacks.

Extra Connections
2 USB2 ports on front of tower – via internal motherboard connection
4 USB2 ports on PCI card (NEC chipset)

Intel Core 2 Duo E6600 2.40 GHz 64 Kb primary cache 4 GB secondary memory cache

4 GB DDR2 in four 1 GB sticks (Vista recognises only 3.326 GB of memory)

ATI Sapphire Radeon X1550 512 MB

Hard Drives
Drive 1 Maxtor STM 3250820 AS 250 GB 8MB SATA 2
Drive 2 Maxtor STM 3250820 AS 250 GB 8MB SATA 2

Floppy Drive
3.5” Samcheer with integral multi card reader

LG GSA 4120B ATA multi drive

LG GSA H42N ATA Double layer multi drive

External Storage
First drive
Seagate 320 GB – 8 MB External USB2
Second drive
Seagate 320 GB – 8 MB External USB2
Third drive
USB2 Enclosure fitted with Seagate 320 GB - 16 MB SATA Hard Disk

LG LGE L226WTQ 22” LCD Widescreen

Epson Aculaser C1100 colour laser
Epson Stylus Photo 750 Inkjet

HP Scanjet G3010

Wireless & cable
Netgear wireless router model
Webstar Cable modem (provided by Telewest)

Operating System
Microsoft Vista Ultimate

  Stuartli 10:51 07 Aug 2007

Ah, Vista....:-)

I would guess that you need Vista compatible drivers for your PCI USB2.0 card and/or external hard drive - whether these are available can only be found out from the respective manufacturer's website.

  jimv7 13:00 07 Aug 2007

Your psu at 380watts, seems a tad small to me for the amount your running off it.

I would go for an external usb2 hub with its own power supply, and take 1 usb card out.

  Quiller. 13:49 07 Aug 2007

Remember also the old addage of " a computers only as fast as it's slowest component "

You are trying to transfer data through a 33Mhz bus, the PCI slot. Even though you are using a usb 2.0 card the system will bottleneck slightly as it goes through the southbridge bus.

Classic PCI
Depending on their size, every desktop computer mainboard has one to five 32 bit PCI adapter slots. This traditional PCI bus transfers 4 bytes of data with every tick of a 33 MHz clock, producing an aggregate bandwidth of 133 megabytes per second. However, this data transfer has to be shared among all of the devices in all of the slots.

There are a limited number of "interrupt levels" available in a PC. One interrupt level can be shared by two or more devices. Each PCI slot is assigned to an interrupt level, and on most mainboards that interrupt level is already in use by some device built into the mainboard (video, disk controller, audio, Ethernet, etc.). This isn't necessarily a problem, but in practice some adapter cards that you buy don't get along well with specific mainboard devices. If a new PCI card is not working correctly, and there is another free slot in the computer, moving the card may cause the problem to go away. This does not mean there is something wrong with the slot. It is probably just an incompatibility with the device that shares the interrupt level with the slot. "

" A car drives down the local streets at 25 miles per hour. Then it turns onto a highway ramp and accelerates to 55. Is there one road system, or two? The important thing is that there is a connection that allows a flow of traffic between the two speed zones. So data may flow from the CPU to the Northbridge at 6400 megabytes/second and then queue up to flow down the PCI bus at 133 megabytes/second. The effective data rate will be the slowest bus speed, but data can flow from any device to any other device. "

from click here

So it could be the fact that it is running through a slower bus plus the facts that otherdevices on the motherboard have to share that bus speed. This you would not get by using the dedicated usb2.0 ports on the motherboard. So that could be the reason why transfering data via a pci card takes longer than using the dedicated ports.

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