Just fix the AHCI already, AMD


— 12:21 PM on August 17, 2009

I've been partial to AMD for a long time. The first PC I built for myself had an Athlon Thunderbird running at a blistering 1.4GHz, and I later upgraded to the Barton-core Athlon XP 2500+. I was one of the lucky ones to get an unlocked model, too, and I took that baby straight up to XP 3200+ speeds. Remember when 200MHz was a major overclock? Crazy kids, spoiled with your Phenom IIs and Core 2s.

When I decided to start using a desktop-replacement notebook instead of a full-on desktop machine, even my shiny new laptop ran a Mobile Athlon 64 3700+, and that thing felt like a demon compared to the XP 2500+. Ultimately, I'd had good experiences with AMD.

After I transferred to the University of California, San Diego, though, I felt like I needed to build a proper desktop for video editing. I also wanted to game on something meatier than a Mobility Radeon X600. Unfortunately for AMD, Intel's Core 2 Duo was beating the Athlon 64 X2 soundly. I built an Intel machine based around everyone's favorite sweet-spot processor at the time, the Core 2 Duo E6600. Since then, the same PC has seen multiple upgrades of all types: video cards, memory, and hard disks. Eventually, even the CPU was upgraded to a Core 2 Quad Q6600—another sweet-spot contender. My Q6600 served me well and overclocked to a smooth 3GHz.

When my birthday came around this year, however, I was given an opportunity to upgrade to an AMD Phenom II. I liked what I'd read about these processors and what they offered, and the chance to have a top-of-the-line CPU for a reasonable price (the Phenom II X4 955 Black Edition with Lettuce, Tomato, and a Side of Mashed Potatoes) was very attractive to me. The Phenom II was ordered, and a friend of mine gave me a spare 790GX-based motherboard as a birthday gift. I was set.

Before getting into what happened, I should mention that as part of having a video editing rig, my scratch disk is a RAID 0 hanging off the south bridge. Intel's south bridges have, in my experience, offered excellent RAID quality. When you're editing high-definition video, you really do need as much storage performance as you can conceivably get so that your hard drives don't bottleneck the processor. A single drive often won't cut it, but a RAID 0 can help shorten render times tremendously.

The reason I bring up RAID is a simple one, and if you've been paying attention to AMD for the past couple years, you may already know where I'm going.

The RAID support on my motherboard's SB750 south bridge was dreadful. Enabling RAID to begin with disabled the expansion card I use to add SATA and eSATA ports, and I could only enable it again once Windows was installed. Also, Windows 7 required a driver installation to detect my optical drive. When I finally got past those hurdles, HDTune was averaging about 100MB/s read for reads on the RAID 0, with a lot of nasty peaks and valleys.

I've seen people get much higher speeds than that with SB750-based RAIDs, so maybe my board was just having trouble handling both a RAID 0 and a RAID 1 at the same time. All I know is that installing Windows and getting everything up and running on Intel's ICH-based RAID is a picnic by comparison. Intel's RAID BIOS is extremely easy to use, and everything registers perfectly fine through the entire Windows setup (and in Windows itself) without the need for separate driver installations. In Windows, the RAID is cheerfully stable, and performance is solid across the board. My ICH10R RAID 0 averages about 160MB/s in HDTune with pretty consistent peaks and valleys.

In addition to the SB750 RAID benching grossly below what it did on the Intel controller and oftentimes even below a single drive, AMD's RAIDXpert software was also downright bizarre. I'm stunned that the RAID manager for integrated south-bridge RAID would run in a browser window and even require a login and password. Not only that, but the software lists the login and password under the boxes as "admin/admin." Seriously? For what it's worth, RAIDXpert was sort of easy to use, but the browser-based interface and "login" screen reeked of a kludge slapped together by people who didn't care. Re-enabling Native Command Queuing on the drives in the RAID didn't solve any of my problems, either; the performance remained identical. Outright deleting the AMD drivers and running off native Windows drivers also did not correct the problem, and it left the RAID running painfully slowly.

The bottom line for me is that I need good, functional RAID—maybe not a full-on card, but at least solid motherboard RAID—and I just wasn't going to get it from AMD. It could very well have just been my board specifically, but you can't deny how poorly the SB750 comes across when it has trouble with one of its most basic applications: moving data on and off of hard disks. A visit here will show the SB750 underperforming due to needing to run in native IDE mode, but the real crime can be witnessed in this review written in late 2007, nearly two years ago. Basic AHCI support still hasn't been fixed.

And I'm sorry, but I'm just not interested in wasting time having to perform some strange driver voodoo to get RAID even working at all. I like the 790GX and was keen to use it to drive a spare monitor, but that just wasn't meant to be.

That's pretty much how AMD lost my business as a user. I instead opted to spend my upgrade funds on an Intel Core 2 Quad Q9650. My motherboard has an Intel RAID controller that works exactly as I'd hoped.

One of the reasons AMD purchased ATI was to have a complete platform, a processor and chipset that could be sold together. I don't like watching AMD play second-fiddle to Intel all the time, but letting even basic hardware AHCI languish like this for nearly two years is inexcusable, let alone the dismal RAID performance.

Sorry, AMD. I think the Overdrive software is a nice touch and your IGP is pretty stellar, all things considered. But the platform you offer me is still missing basic functionality other vendors deliver. Maybe when you can get your south bridges sorted out, maybe in the next generation, we can talk, but for now I'll be just fine with my Core 2 Quad and ICH10R. What good is offering RAID in all of your south bridges when it barely works?

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