eSATA help and AHCI thanks

Meridiusuk · 31 Jan 2010 at 13:36

hi all

can anyone help me here i have read that using AHCI will enable NCQ and lets you have hot swap for external esata device when you turn it on in the bios.

the thing is i have a sata pioneer writer will this effect that as i have read thta this might casue problems?

the motherboard i am getting has a esata on the back of the i/o plate as well as thismis an asus pd55 i5

can anyone give me help on this

thanks

rpstewart · 31 Jan 2010 at 14:23

There won't be any problem running the DVD drive on a controller in AHCI mode.

Sylver123 · 31 Jan 2010 at 17:02

I take it turning AHCI mode on in the bios when it's normally set on IDE won`t affect the operation nor the performance of Internal SATA Hard Drives that are conected???

Thanks for responding.

rpstewart · 31 Jan 2010 at 17:16

NCQ can have a slight negative impact on performance in a desktop environment but other than that there's no difference.

Meridiusuk · 31 Jan 2010 at 17:59

rpstewart said:
NCQ can have a slight negative impact on performance in a desktop environment but other than that there's no difference.

what do you mean ? i thought NCQ improved performance ? why is this not on by default ? is there anything i need to look out for.

the reason i ask is i have a case that has a esata on the front and have been toled the only way to use it is to turn on AHCI but i have also read that some people have problems with sata dvd drives when you select AHCI

thanks

nightmare99 · 31 Jan 2010 at 18:05

If you are running XP you will need to take some extra steps to make sure you can boot up after switching to AHCI. If you are running Vista or Windows 7 you just need to enable the MSAHCI service before turning it on in the BIOS.

rpstewart · 31 Jan 2010 at 18:12

Meridiusuk said:
what do you mean ? i thought NCQ improved performance ?

The problem with NCQ is that it's implemented on the drive itself so has no way of telling whether it's actually helping or not. For example if the OS needs blocks A, B then C in that order but A & C are actually next to each other the drive can send A, C then B so the OS has to discard C and re-request it after B has arrived.

Meridiusuk said:
the reason i ask is i have a case that has a esata on the front and have been toled the only way to use it is to turn on AHCI but i have also read that some people have problems with sata dvd drives when you select AHCI

thanks

You don't need AHCI enabled to use eSATA, it just makes it a little easier. You can do exactly the same thing with the controller in IDE mode if you use Hotswap!

Meridiusuk · 31 Jan 2010 at 18:41

when i install windows 7 do you think i should turn it on in the bios then or not bother with it?

or is it best to use it for the NCQ do you all use it ?

thanks

Sylver123 · 31 Jan 2010 at 18:50

Yeah, but when using a external hard drive as eSATA with no AHCI enabled, would it still be safe to disconnect the drive whilst the computer is still running and still it windows???