[9fans] Re: nvidia scrolling performance

["Paweł Lasek" <pawel.lasek@gmail.com>]

On 5/1/06, erik quanstrom <quanstro@quanstro.net> wrote:
>....
> PCIe SLI = 2 * 16x = 8G/s, which ought to be enough for just about anyone.

Looks like I have to disrupt some pleasant assumptions....

PCI-Express cards don't give a damn about the number of lines that are
connected ("1x" means one pci-express line), the only thing it changes
is the transfer speed.

And except for workstation (traditional sense of specialized mb and so
on) or special gaming motherboards I have yet to hear about a SLI
motherboard with 32 PCI-express lines.... (Standard PC motherboards
have 20 lines, latest PowerMacs have at least 32 lines - 1*16x 1*8x
2*4x + 4x ones have 8x physical connectors to use 8x cards in 4x mode,
maybe more - need to visit an Apple Store...)

Actually, when you use the switch (hardware or software) to change
into sli mode, you split 8 lines from "normal" port to "second",
making them 2* 8x ports :)

Of course, using special chips (like workstation line of Nforce, hard
to get from what I heard, allows you to build up to *LOT* of lines
:P), you can get the required 32 lines to get both cards working at
2*16x (PCI-Express defines single ports with up to 32x lines)

Of course, each line is 250 MiB/s bi-directional full-duplex (On
PCI-Express, reading from video memory is fast enough, shortly
speaking - it's the core factor for nVidia/ATI low-budget cards like
"Turbo Cache" and so on....)

> - erik

Over 4 years of trying to buy a new computer - At least I learned a
little from it :D
(Basically all my hardware is n-hand.... and people ask why it
sometimes it just doesn't work!? Not to mention that it's hard to get
i440bx compatible sdrams these days...)

--
Paul Lasek