[conspire] How to check if a mobo is compatible with

[Mike Higashi]

On Sun, Mar 30, 2008 at 2:18 PM, Rick Moen <rick at linuxmafia.com> wrote:
> Quoting David Fox (dfox94085 at gmail.com):
>
>  Quite.  It's important to realise that, with ATA (PATA or SATA), the
>  theoretical bus-speed limit is almost never the limiting factor.  The
>  bus ceiling is typically so extremely high compared to the speed of
>  physically reading data from the hard drive in all but very artificially
>  contrived situations (and maybe not even then) that, e.g., 150 vs 300
>  MB/sec speed limits on the HBA bus really don't make a damned bit of
>  difference.

This isn't an area that I've throughly investigated, but I suspect that the
situation is somewhat better than you believe, largely due to the universal
adaptation of RAM-based buffers on board hard drives.

How much of an improvement would depend on the type of read or write
access -- random reads would show no improvement, but sequential reads
could use look-ahead buffering to prefetch the next read, which would then
be transferred at the maximum rate.

Under certain situations, disk writes would also seem to be faster. After
the buffer on the hard drive accepts data to be written, the hard drive can
send a signal back to the kernel saying the write is complete, even though
the data hasn't been fully committed to disk.

All in all, disk throughput is still the ultimate bottleneck, but having higher
transfer rates allows your system to feel more responsive in some
situations.

Mike