"40 pins" ATA adapter cables for 2.5 PATA?

[BusError]

I'm using a 3.5 to 2.5 ATA cable in my SFF, and linux keeps telling me that it degraded the speed down to ATA/33 because I'm using a "40 pins cable" and not a "80 pins cable"
Well, technicaly it's true, the I'm wondering why it should degrade the performance.. the 80 cables are just the same as the 40 but serves two disks on the same cable (master, slave)

Anyone knows if it's an old-time sort of precaution and could be ignored with modern '40' cables ?

 

[BusError]

Well, I have that 160GB PATA disk lying around, and the SATA ports are used by my CF RAID1 array.

So I'll stick to what I have, the speed is not a big problem as it's not the system disk.. It's just slightly nagging

 

[BusError]

Technicaly it's 40 pins. but I don't see how it can be worse than a 80 pins cable with one disk missing. I understand LVDS pairs more than most, and I know how they work, but IDE/ATA is not like that at all, so a modern 40 pin cable /should/ work as good as a 80 one.