GIGABIT LAN bottleneck?

  • Thread starter Thread starter jtsnow
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jtsnow

Will I experience significantly faster exchange on my home LAN then with
100baseT thats there now?
Is there a bottle neck limitation in the PC that limits the max amount of
effective throughput to the point where it wont make much difference to hang
a GIGABIT LAN around it?
I have 4 PCs on a home LAN I was considering doing this for to improve HD
backup times I do to a server and to help with other shared bandwidth issues
we are starting to see with the kids playing online games, backups and such.

Any thoughts to suggest if this its worth the trouble to swap out NICs and
router to the GIGBIT world?.

Thank for any insights
 
jtsnow said:
Will I experience significantly faster exchange on my home LAN then with
100baseT thats there now?
Is there a bottle neck limitation in the PC that limits the max amount of
effective throughput to the point where it wont make much difference to hang
a GIGABIT LAN around it?
I have 4 PCs on a home LAN I was considering doing this for to improve HD
backup times I do to a server and to help with other shared bandwidth issues
we are starting to see with the kids playing online games, backups and such.

Any thoughts to suggest if this its worth the trouble to swap out NICs and
router to the GIGBIT world?.

Thank for any insights
Click to expand...
If my experience is any indicator, you will get a modest increase in
throughput.

I believe the PCI bus in most PCs is a bottleneck when gigabit speeds
are involved.
 
If my experience is any indicator, you will get a modest increase in
throughput.

I believe the PCI bus in most PCs is a bottleneck when gigabit speeds are
involved.
Click to expand...

And even when going from 10Mb to 100Mb the difference
doesnt exactly blow your sox off with most real world situations.

The only thing I do much that is theoretically affected is doing
imaging to a drive on the other side of the lan and none of the
current imaging apps like ghost or true image get even close
to saturating the lan link even with 100Mb.
 
very nice insight. Sounds like not worth the expense for me until I get a
PC that can handle the interface speed.
 
jtsnow said:
Will I experience significantly faster exchange on my home LAN then with
100baseT thats there now?
Is there a bottle neck limitation in the PC that limits the max amount of
effective throughput to the point where it wont make much difference to
hang a GIGABIT LAN around it?
I have 4 PCs on a home LAN I was considering doing this for to improve HD
backup times I do to a server and to help with other shared bandwidth
issues we are starting to see with the kids playing online games, backups
and such.

Any thoughts to suggest if this its worth the trouble to swap out NICs and
router to the GIGBIT world?.
Click to expand...

A good PCI-based server with a fast disk subsystem can sustain about 400
Mb/sec on a Gigabit LAN. First thing to determine is if you are hitting
100 Mb/sec--if you're not close to that then gigabit won't help, if you are
then it likely will.
 
CJT said:
If my experience is any indicator, you will get a modest increase in
throughput.

I believe the PCI bus in most PCs is a bottleneck when gigabit speeds
are involved.
Click to expand...

Not if only one of the interfaces (whether source or destination device)
is on the PCI bus.
 
Previously J. Clarke said:
jtsnow wrote:
Click to expand...
A good PCI-based server with a fast disk subsystem can sustain about 400
Mb/sec on a Gigabit LAN. First thing to determine is if you are hitting
100 Mb/sec--if you're not close to that then gigabit won't help, if you are
then it likely will.
Click to expand...

I did measurements on this some time ago. PCI card in several
different mainboards: 250-350Mb/s. Special combination (tested
in c't): 450Mb/s in a slot where the IRQ had other devices on it,
600Mb/s with its own IRQ. Both under Linux (the MB is not sold
anymore so no point in posting which it was). Measurements
were without disk load.

Whether an on-board card is on the PCI-bus or on something faster
depends.

Also around 600Mb/s with a 64bit PCI card in a 64bit/66MHz PCI bus.

Bottom-line: For higher performance you need something else than
normel PCI or _very_ careful tuning. You can get 250-350Mb/s by
just using a generic, low-cost card in a PCI slot.

For your HD backup, if the disk system is fast (say, 40MB/s
= 400Mb/s, including overhead), you begin to go into
the range where the PCI bus matters. Of course it depends
also on you networking stack and other OS-dependent factors.

I would say by just using generic GbE cards you should
get at least a speed-up of x 2, unless your OS or disks
are really slow. No promises though.

One thing that is nice about GbE is that all ports are symmetrical,
i.e. no need for cross-over cables anymore.

You should also use Cat 5e cable for all lines longer than
a few meters and need 8-lane cables for all lines, otherwise
they will drop back to 100Mb/s.

Arno
 
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