How much swap on laptop?

[James Wilkinson]

Hadders wrote:
> Thanks. I wonder what the "real" world performance of my SATA disks is
> then?

Depends on your computer. At the moment, if you're just using one disk,
then that will still be the limitation unless the data is going to (or
coming from) another computer via a gigabit Ethernet card on the same
PCI bus.

Even with RAID, you're *still* likely to be limited by the disks unless
you're streaming a large file to or from the disks as quickly as they can
read or write it.

> My knowledge is that the PCI bus interfaces with the Northbridge
> chipset

If your chipset supports AGP 4x or greater and ATA-66, then there's
usually a PCI-like link (only faster) between the North Bridge and the
South Bridge, and PCI itself comes off the South Bridge. On some
chipsets (SiS630, Nforce 3 and early Nforce 4), there *is* only one chip
in the chipset.

See http://www.intel.com/products/i/chipsets/925X/925x-flowlarge.jpg for a
typical modern chipset layout.

This means that devices on the chipset will get to share that high speed
link and won't be limited to 133 MB/s. It also usually means that there
*is* 133 MB/s free for "real" PCI devices.

> and 
> that chipset then talks to the Main memory, CPU and AGP/PCIe?

Unless you've got a recent AMD CPU, which can talk to memory directly.

> So, my hard disks have to share the 133MB/s with the ethernet and any
> other PCI devices (like my Audigy), does the USB also run across this
> and interface in from the South bridge?

Depends. You may have all your network, SATA and USB support in the
South Bridge, your network card may have its own link to the chipset,
your motherboard manufacturer may have implemented any of them as
separate PCI chips on that 133 MB/s bus (but soldered them to the
motherboard), or you may have separate cards.

Putting everything on traditional PCI will be a limitation.

Hope this helps,

James.

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