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So I'm about to upgrade my laptop (Lenovo 3000 N100, 0768-49G), got my SATA HDD caddy for the DVD-ROM slot, but whenever I'm putting an HDD or SSD into it, the read speed falls to only 30 MByte/s, whereas the same drive put into the regular HDD slot scores over 130 MBytes/s (max. possible on this old PATA bus). I'm testing from a Live-CD using Ubuntu's "disk utility".

I've got the latest BIOS (Phoenix 2.06, 61ET37WW), it looks like some extremely cut version of the original bios - I can't change anything hardware related (like AHCI/IDE mode for the SATA controller), the only available settings are "quite boot", "enable modem" and "enable legacy usb".

So my question is: why is the SATA port in the DVD slot so much slower? Is there any way to get the same speed (130+ MB/s) on both ports so I can use SSD and HDD in parallel?

Thanks!

UPDATE 1 I may have found something relevant in dmesg:

[    1.390619] ata1: SATA max UDMA/133 cmd 0x1f0 ctl 0x3f6 bmdma 0x18b0 irq 14
[    1.390626] ata2: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0x18b8 irq 15
[    1.556337] ata1.00: ATA-9: Samsung SSD 840 Series, DXT06B0Q, max UDMA/133
[    1.556345] ata1.00: 234441648 sectors, multi 16: LBA48 NCQ (depth 0/32)
[    1.561011] ata2.00: ATA-8: WDC WD7500BPKT-00PK4T0, 01.01A01, max UDMA/133
[    1.561018] ata2.00: 1465149168 sectors, multi 16: LBA48 NCQ (depth 0/32)
[    1.561027] ata2.00: limited to UDMA/33 due to 40-wire cable
[    1.564333] ata1.00: configured for UDMA/133

what's that "40-wire cable"?

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    do you have the 'old style' DVD connector or the sata style one?
    – Journeyman Geek ♦
    Commented Jan 3, 2013 at 1:05
  • The caddy looks like this. I hope you can see the connectors on the picture. Does this answer your question?
    – Pavel
    Commented Jan 3, 2013 at 1:10
  • Yes, those are SATA connectors.
    – cpast
    Commented Jan 3, 2013 at 1:38
  • Thanks! Is it perhaps some hardware limitation of the caddy?
    – Pavel
    Commented Jan 3, 2013 at 2:01
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    Wait, no, they're not SATA. Sorry, it seems that I'm blind. The caddy takes a SATA hard drive, but has an "old style" DVD connector. Sorry for the mistake.
    – cpast
    Commented Jan 3, 2013 at 2:56

1 Answer 1

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Its using an oldschool atapi connector rather than sata, and as I recall the core 2 era lenovos use SATA for the hard drive and a backward compatible atapi connector for the cd rom drives. ATAPI is pretty much pata so I suspect the drive caddy downconverts the SATA connection to PATA, which explains the slower speed.

From your paste, its also running at an older, slower pata standard.

80 wire pata cables are newer and were an attempt at reducing signal noise, It added 40 dedicated grounding cables to the standard ribbon cable. On a desktop these are the cables with specific colours per port (blue, black and grey), and generally the sort you'd want to use for best performance. Wikipedia goes into some depth on the subject but in a nutshell, its the caddy and its interface with the laptop. My guess is the laptop's optical drive uses the older PATA standard to save costs, and cause cd drives weren't that performance sensitive. This results in your drive being slower.

enter image description here

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  • Ok, that sounds reasonable, thank you for a detailed answer! I guess, I have to admit that there are limits on upgrading old laptops...
    – Pavel
    Commented Jan 3, 2013 at 14:45

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