If you have a computer built around a ASUS M3A78-EM motherboard, or more generally a motherboard with a AMD SB700 southbridge, running Ubuntu Linux and VMware Server, but very very painfully due to unduly ridiculously slow hard drive, blacklist ata_generic and add pata_atiixp to /etc/initramfs-tools/modules.
What was specifically happening in my case was somewhat different than the person in the linked thread was experiencing: DMA appeared to be on, and immediately after boot-up speeds were okay. However, using any VMs quickly killed the speeds. With the change, the speeds stay where they’re supposed to be. In my case, it’s consistently around 106 MB/s from a Samsung HD502HI when it’s idle.
The rudimentary benchmark I used was
sudo hdparm -tT /dev/sda.
I was going to post this to Twitter; then I thought about it and figured a bit more commentary couldn’t hurt, and this way I am not at mercy of Twitter’s hyperlink
breaker shortener du jour.
Not to mention this should Google better.