Speed windows xp on external usb harddrive using VirtualBox on mac

Former Member

I am considering to install windows xp on external usb harddrive through VirtualBox but i was worried about its speed. Will it be OK to do this? Should i be worried about anything?

Former Member

I doubt it'll be anywhere near fast enough. Whilst transfer speeds on external hard drives are good, they're nowhere near upto the standard of an internal drive. My internal drive is a third generation SATA drive, and it has a transfer rate of about 250Mb a second. The external drive gets about 25Mb a second. it's fast enough for backing stuff up on, but nowhere near enough to run a programme, especially not one as big and complex as an operating system.

Former Member

25mb per second? That's far from being unusable. You'll often see 30-50mb per second on an internal drive.

Just benchmarked my drives...

dev/sda:

 Model=Hitachi HDS721616PLAT80                 , FwRev=P22OA60A, SerialNo=      <snip>
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=51
 BuffType=DualPortCache, BuffSize=7384kB, MaxMultSect=16, MultSect=?16?
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=321672960
 IORDY=on/off, tPIO={min:240,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4
 DMA modes:  mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5 udma6
 AdvancedPM=yes: disabled (255) WriteCache=enabled
 Drive conforms to: ATA/ATAPI-7 T13 1532D revision 1:  ATA/ATAPI-2,3,4,5,6,7

/dev/sdb:

 Model=Hitachi HDP725050GLA360                 , FwRev=GM4OA5CA, SerialNo=      <snip>
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=56
 BuffType=DualPortCache, BuffSize=15118kB, MaxMultSect=16, MultSect=?16?
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=976773168
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4
 DMA modes:  mdma0 mdma1 mdma2
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6
 AdvancedPM=yes: disabled (255) WriteCache=enabled
 Drive conforms to: unknown:  ATA/ATAPI-2,3,4,5,6,7

/dev/sda:
 Timing cached reads:   2018 MB in  2.00 seconds = 1008.58 MB/sec
 Timing buffered disk reads:  218 MB in  3.00 seconds =  72.55 MB/sec
click@toseemore:/dev$ sudo hdparm -tT /dev/sdb

/dev/sdb:
 Timing cached reads:   2240 MB in  2.00 seconds = 1119.57 MB/sec
 Timing buffered disk reads:  274 MB in  3.01 seconds =  90.96 MB/sec
click@toseemore:/dev$

Cache readings are largely useless. And don't believe the hype of published transfer speeds.

It won't be as fast as an internal hard drive - but it'll be perfectly usable. Especially in the real world, where data is accessed from all over the drive, rather than reading a huge continuous stream of data...