Building new comp, AHCI/write-back caching question

[Freshman]

First of all, I started lurking these boards around 3 weeks ago as my primary reference site when I started shopping for a new computer. There is a lot of great computer minds and advice here and I appreciate this site for it's users and wealth of comprehensive information.

On to my topic: Tomorrow all the parts for my new comp (core parts listed in signature) will be arriving. I'm confident about my ability to assemble all the hardware, but there has been one particular subject I got lost on. A few websites said I need to enable AHCI in my BIOS before installing, and write-back caching once Vista is installed. On the other hand, an equal number of sites I found googling recommended against it. I tried asking some people over instant messenger programs that are more knowledgable than me and again got mixed answers.

I am not particularly learned about computers in general, I know how to assemble the hardware and have an above-average comprehension of software and Windows, but this is way above my level. I have absolutely no idea what I should be doing at all. If someone would please be kind enough to break it down a bit to more layman's terms and offer some advice I would be deeply appreciative.

 

[Syntax Error]

You don't really need AHCI if you don't intend to hotswap drives or use NCQ - either of these features wouldn't increase performance noticeably anyways. If you were to enable it, you have to have to install Windows with the setting installed, otherwise just turning on ACHI one day on a Windows install through the BIOS would cause BSODs during bootup.

 

[Freshman]

Alright, thank you. What should be enabled then in BIOS? Just whatever the default is set to?

 

[Syntax Error]

Your SATA drives should be in default IDE emulation mode (usually, mobos have three options for SATA disks: IDE, SATA/RAID, and AHCI). Keep it at the former, to keep things simple if you intend on just using one logical partition per physical drive and not mess with RAID.

 

[Forceman]

If you are using Vista there really isn't a downside to using AHCI; it doesn't cost anything, Vista has built-in AHCI support so you don't need a driver floppy like you did with XP, and you get the ability to hotswap drives, which I didn't think would be a big deal but which I now use all the time to connect external drives for backups. Normally I'd recommend sticking with IDE mode (and it certainly works fine), but with a new Vista install I'd go AHCI.

 

[lawrence131]

Some very experienced guys have done dozens and dozens of tests on this subject over at storagereview as it is a pretty confusing topic that has changed over the last few years. NCQ affects different drives differently and different tasks differently. It also has been poorly implemented for Windows users for years. For single application/single user cases it likely doesn't matter, but overall you should have small gains with AHCI vs IDE mode (there are more instances where AHCI beats IDE than vice versa).

If you are setting up a new computer there isn't really a large drawback to taking the extra few minutes to setup AHCI properly on an XP machine. If it's already in IDE mode with XP installed, you'll have to decide if it's worth hours of work (requires reinstall after BIOS change) for a small performance gain. There are specific instances where the gains are very large (see the tests done at storagereview), but the overall improvement is felt to be small.