quad sli = how many video ports? matrox dual head2go x 2?

markm75 · Joined: 18 Nov 2007 Posts: 7

Does anyone know with a quad sli setup, how many video ports this
enables.. ie: with regular sli.. you only end up with 2 DVI out of 4..
so do you end up with 4 on a quad sli setup and how do you know which
ports are active?

Also.. has anyone tried the dual or tri matrox2go setups.. if i'm
running 1900x1080 (1080p) on a 24".. would i be able to hook one of
these to a single DVI port and then have two LCDS at the same
resolution each (or one LCD and an HDTV via the HDMI port)?

Any thoughts?

Thanks

Archived from group: alt>comp>periphs>videocards>nvidia

Benjamin Gawert · Joined: 22 Aug 2007 Posts: 423

* markm75:

> So with a dual video card (sli) setup.. you are saying that even
> though there are 4 DVI ports.. only 1 is active.. or are you saying 2
> are active (one card)...

*ONE* port. No matter how much cards are involved.

Benjamin

Mr.E Solved! · Joined: 22 Aug 2007 Posts: 497

Paul wrote:

> With regard to SLI, one of the concerns I'd have, is how the
> mapping of the memory on the SLI cards, eats into the available
> address space left for system memory.

Eh? You think SLI negatively impacts system memory availability?

> If the cards purchased
> had large texture memories, then there is less room in a
> 32 bit OS, for system memory. (On the A8N-SLI with a couple
> good cards in it, that is why you'd install 4GB of RAM, and
> only get to see 2.5GB in a 32 bit Windows OS.) I don't know
> if the solution is a 64 bit OS or not.

Ah you think that video memory and system memory combined have to be
less than 3.5GB in Windows XP and this is why video cards have less than
1G of video memory?

You really twisted yourself up in a logic knot with that one: so that
means any Windows XP (32bit) system with 4G of system memory with a 1G
video card means there is -1.5G of system Ram available? And 2G of
system ram plus a 1G SLI = .5G available?

Paul · Joined: 22 Aug 2007 Posts: 200

Mr.E Solved! wrote:
> Paul wrote:
>
>> With regard to SLI, one of the concerns I'd have, is how the
>> mapping of the memory on the SLI cards, eats into the available
>> address space left for system memory.
>
> Eh? You think SLI negatively impacts system memory availability?
>
>> If the cards purchased
>> had large texture memories, then there is less room in a
>> 32 bit OS, for system memory. (On the A8N-SLI with a couple
>> good cards in it, that is why you'd install 4GB of RAM, and
>> only get to see 2.5GB in a 32 bit Windows OS.) I don't know
>> if the solution is a 64 bit OS or not.
>
> Ah you think that video memory and system memory combined have to be
> less than 3.5GB in Windows XP and this is why video cards have less than
> 1G of video memory?
>
> You really twisted yourself up in a logic knot with that one: so that
> means any Windows XP (32bit) system with 4G of system memory with a 1G
> video card means there is -1.5G of system Ram available? And 2G of
> system ram plus a 1G SLI = .5G available?
>
>

OK, you explain it, and we'll review your work.

Thanks,
Paul

Benjamin Gawert · Joined: 22 Aug 2007 Posts: 423

* Mr.E Solved!:

>> With regard to SLI, one of the concerns I'd have, is how the
>> mapping of the memory on the SLI cards, eats into the available
>> address space left for system memory.
>
> Eh? You think SLI negatively impacts system memory availability?

Every expansion card eats into the I/O address space that traditionally
sits below the 4GB memory mark and which is not available to the OS any
more. A gfx card with 256MB extends this I/O range to 256MB, a gfx card
with 512MB extends the I/O range to 512MB and two gfx cards with 512MB
extend the I/O range to 1GB.

The only way to avoid that is memory hoisting which pushes the I/O space
above the installed physical memory. This requires a computer with
memory hoisting support in its BIOS and a memory hoisting aware OS that
can deal with more than 4GB RAM, which praktically means you need a
64bit system with 64bit OS.

>> If the cards purchased
>> had large texture memories, then there is less room in a
>> 32 bit OS, for system memory. (On the A8N-SLI with a couple
>> good cards in it, that is why you'd install 4GB of RAM, and
>> only get to see 2.5GB in a 32 bit Windows OS.) I don't know
>> if the solution is a 64 bit OS or not.
>
> Ah you think that video memory and system memory combined have to be
> less than 3.5GB in Windows XP and this is why video cards have less than
> 1G of video memory?

He is right. A standard PC usually has an I/O space size somewhere
between ~300-700MB. Note that the I/O space hangs directly below 4GB, no
matter how much RAM is in the computer. Back to the example he listed,
if you have a system with two 512MB gfx cards in SLI and some other
stuff (sound, tv card etc) you can end up Windows not seeing more than
2.5GB no matter how much memory is in the system (4GB adress range minus
2x 512MB for every gfx card and say another 512MB for the I/O
requirements of other devices which sums up to an I/O space of 1.5GB).

But as I said, all this is only valid if you use an 32bit Windows that
only supports 4GB of RAM (the 32bit Server versions support more through
PAE). If you run a 64bit Windows and if your computer supports memory
hoisting then the I/O space isn't an issue any more.

Benjamin

Benjamin Gawert · Joined: 22 Aug 2007 Posts: 423

* Mr.E Solved!:

>> With regard to SLI, one of the concerns I'd have, is how the
>> mapping of the memory on the SLI cards, eats into the available
>> address space left for system memory.
>
> Eh? You think SLI negatively impacts system memory availability?

Every expansion card eats into the I/O address space that traditionally
sits below the 4GB memory mark and which is not available to the OS any
more. A gfx card with 256MB extends this I/O range by 256MB, a gfx card
with 512MB extends the I/O range by 512MB and two gfx cards with 512MB
extend the I/O range by 1GB.

The only way to avoid that is memory hoisting which pushes the I/O space
above the installed physical memory. This requires a computer with
memory hoisting support in its BIOS and a memory hoisting aware OS that
can deal with more than 4GB RAM, which praktically means you need a
64bit system with 64bit OS.

>> If the cards purchased had large texture memories, then there is
>> less room in a 32 bit OS, for system memory. (On the A8N-SLI with a
>> couple good cards in it, that is why you'd install 4GB of RAM, and
>> only get to see 2.5GB in a 32 bit Windows OS.) I don't know if the
>> solution is a 64 bit OS or not.
>
> Ah you think that video memory and system memory combined have to be
> less than 3.5GB in Windows XP and this is why video cards have less
> than 1G of video memory?

He is right. A standard PC usually has an I/O space size somewhere
between ~300-700MB. Note that the I/O space hangs directly below 4GB, no
matter how much RAM is in the computer. Back to the example he listed,
if you have a system with two 512MB gfx cards in SLI and some other
stuff (sound, tv card etc) you can end up Windows not seeing more than
2.5GB no matter how much memory is in the system (4GB adress range minus
2x 512MB for every gfx card and say another 512MB for the I/O
requirements of other devices which sums up to an I/O space of 1.5GB).

But as I said, all this is only valid if you use an 32bit Windows that
only supports 4GB of RAM (the 32bit Server versions support more through
PAE). If you run a 64bit Windows and if your computer supports memory
hoisting then the I/O space isn't an issue any more.

Benjamin

Mr.E Solved! · Joined: 22 Aug 2007 Posts: 497

Benjamin Gawert wrote:

> He is right.

No he isn't and you know it. I thought you were informed Benjamin.

System RAM addressing limitations (of said OSes) have nothing to do with
what expansion cards are in your system. They exist regardless of what
card(s) you have installed.

This isn't theoretical, check it yourself on your own PC.

Mr.E Solved! · Joined: 22 Aug 2007 Posts: 497

Paul wrote:

> OK, you explain it, and we'll review your work.

Explain what?

Why 4G of system memory isn't displayed as 4G in those OSes? That
question has been asked and answered for years now and it has nothing to
do with video cards, or video memory on those cards.

Google it yourself.

Paul · Joined: 22 Aug 2007 Posts: 200

Benjamin Gawert wrote:

>
> The thing is: using tripple or quad SLI on PC running 32bit Windows can
> easily eat up a big amount of your RAM. Two 512MB gfx cards reduce
> useable RAM by 1GB, three of these cards already reduce available memory
> by 1.5GB. Four cards in quad SLI alone would eat up 2GB of your 4GB
> adress space, leaving you with less than 2GB (2GB minus the I/O space
> required by all the other devices) on a PC with 4GB RAM.
>
> Of course, if your PC only has 2GB memory, you won't notice any
> difference in memory useage between say a single 512MB card and a SLI
> setup of two 512MB cards, at least as long as the I/O space doesn't
> reach down to 2GB.
>
> Benjamin

And that is my point. As you add more video cards, the address space usage
increases, based on the amount of memory on each video card that needs
to be addressed. The BIOS insists on reserving address space for every
byte of RAM offered by the video card. So four 512MB video cards, need
2GB of I/O space out of the 4GB of address space available in a 32 bit
OS. If you install only 2GB of RAM, none is wasted. If you installed
4GB of RAM in that system, then only 2GB is addressable. The other
2GB sits in the machine, but cannot be accessed by a 32 bit OS. If
the chipset supports remapping, and you have a 64 bit OS, then things
will be better, but then you need to deal with a 64 bit OS (drivers etc).

(Intel needs to update this document, with examples of what happens when
more than one video card is installed. Asus got this from Intel, but
I cannot find the original on the Intel site. The A8N-SLI results with
two video cards, were the first I'd heard of someone only being able to
see 2.5GB of the 4GB of RAM they installed.)

http://dlsvr01.asus.com/pub/ASUS/mb/4GB_Rev1.pdf

Whether this is an issue, depends on whether FSX uses a lot of memory
or not. Before FSX had a service pack, people tried throwing all manner
of expensive hardware at it, to try to make it better. The biggest
improvement came when SP1 was released.

Judging by the benchmarks I can still find though, the program
is still a resource hog, and almost impossible to satisfy. Maybe
that is the way the developers want it, but how that helps them
escapes me.

I'd hoped that things like quad core processors would make a
difference, but the loading pattern is not symmetric. One
core is always "to the wall", while the others are loafing.
Which makes me wonder whether a dual that can be overclocked
further than a quad, might work better. The developer blogs
are still referring to 20-30FPS as their targets.

Paul

Mr.E Solved! · Joined: 22 Aug 2007 Posts: 497

Paul wrote:

> http://dlsvr01.asus.com/pub/ASUS/mb/4GB_Rev1.pdf

Hi, thanks February 2005 for that link, you aren't breaking new ground,
remapping memory is common practice and hasn't been impactful on
performance.

Everyone knows a 64-bit environment brings more address space, it's the
only real benefit. Video card memory sizes have very little to do with
it, it's why video cards have memory on them, duh.

Benjamin Gawert · Joined: 22 Aug 2007 Posts: 423

* Mr.E Solved!:

>> He is right.
>
> No he isn't and you know it. I thought you were informed Benjamin.

Then maybe either I or you misunderstood his posting (could of course be I).

> System RAM addressing limitations (of said OSes) have nothing to do with
> what expansion cards are in your system. They exist regardless of what
> card(s) you have installed.

Yes, you're right of course. But there are two sides: one side is the
RAM limit of 32bit desktop Windows which only can address 4GB. The other
side is the I/O space which eats up some space in this 4GB adress.

> This isn't theoretical, check it yourself on your own PC.

Not necessary as I already played around with these things. For example,
I have a smaller PC with shared memory gfx that has 4GB RAM installed
running Vista 32bit. Vista can see ~3.7GB of RAM, the rest is used as
I/O address space by the integrated components. For testing purposes I
have put a Quadro FX 5500 gfx card with 1GB memory in this computer, and
both Vista 32bit and Windowsxp 32bit only could see ~2.3GB of RAM. This
is due to the I/O space eaten up by the gfx card.

The thing is: using tripple or quad SLI on PC running 32bit Windows can
easily eat up a big amount of your RAM. Two 512MB gfx cards reduce
useable RAM by 1GB, three of these cards already reduce available RAM by
1.5GB. Four cards in quad SLI would eat up 2GB of your 4GB adress
space, leaving you with less than 2GB (2GB minus the I/O space required
by all the other devices) on a PC with 4GB RAM.

Of course, if your PC only has 2GB memory, you won't notice any
difference in memory useage between say a single 512MB card and a SLI
setup of two 512MB cards, at least as long as the I/O space doesn't
reach down to 2GB.

Benjamin

Benjamin Gawert · Joined: 22 Aug 2007 Posts: 423

* Mr.E Solved!:

>> He is right.
>
> No he isn't and you know it. I thought you were informed Benjamin.

Then maybe either I or you misunderstood his posting (could of course be I).

> System RAM addressing limitations (of said OSes) have nothing to do
> with what expansion cards are in your system. They exist regardless
> of what card(s) you have installed.

Yes, you're right of course. But there are two sides: one side is the
RAM limit of 32bit desktop Windows which only can address 4GB. The other
side is the I/O space which eats up some space in this 4GB adress.

> This isn't theoretical, check it yourself on your own PC.

Not necessary as I already played around with these things. For example,
I have a smaller PC with shared memory gfx that has 4GB RAM installed
running Vista 32bit. Vista can see ~3.7GB of RAM, the rest is used as
I/O address space by the integrated components. For testing purposes I
have put a Quadro FX 5500 gfx card with 1GB memory in this computer, and
both Vista 32bit and Windowsxp 32bit only could see ~2.8GB of RAM (3.7GB
plus the 1GB from the gfx card minus the ~128MB of the now unused
onboard gfx). This is due to the I/O space eaten up by the gfx card.

The thing is: using tripple or quad SLI on PC running 32bit Windows can
easily eat up a big amount of your RAM. Two 512MB gfx cards reduce
useable RAM by 1GB, three of these cards already reduce available memory
by 1.5GB. Four cards in quad SLI alone would eat up 2GB of your 4GB
adress space, leaving you with less than 2GB (2GB minus the I/O space
required by all the other devices) on a PC with 4GB RAM.

Of course, if your PC only has 2GB memory, you won't notice any
difference in memory useage between say a single 512MB card and a SLI
setup of two 512MB cards, at least as long as the I/O space doesn't
reach down to 2GB.

Benjamin

GMAN · Joined: 27 Jan 2008 Posts: 9

In article , "Mr.E Solved!" wrote:
>Paul wrote:
>
>> http://dlsvr01.asus.com/pub/ASUS/mb/4GB_Rev1.pdf
>
>Hi, thanks February 2005 for that link, you aren't breaking new ground,
>remapping memory is common practice and hasn't been impactful on
>performance.
>
>Everyone knows a 64-bit environment brings more address space, it's the
>only real benefit. Video card memory sizes have very little to do with
>it, it's why video cards have memory on them, duh.

It has everything to do with how much memory is left over

The amount of memory on a video card has to be addressed or allowed for. So
yes the amount of memory does effect how much ran you have left over. When i
had a cheap 7600GS video card with 256 mb ram, i had nearly 3.5 GB ram on my
Windows XP Asus Commando motherboard. Once i went to a 8800GTS 640MB unit, i
only have 3 GB

Mr.E Solved! · Joined: 22 Aug 2007 Posts: 497

GMAN wrote:
> In article , "Mr.E Solved!" wrote:
>> Paul wrote:
>>
>>> http://dlsvr01.asus.com/pub/ASUS/mb/4GB_Rev1.pdf
>> Hi, thanks February 2005 for that link, you aren't breaking new ground,
>> remapping memory is common practice and hasn't been impactful on
>> performance.
>>
>> Everyone knows a 64-bit environment brings more address space, it's the
>> only real benefit. Video card memory sizes have very little to do with
>> it, it's why video cards have memory on them, duh.
>
>
> It has everything to do with how much memory is left over
>
>
> The amount of memory on a video card has to be addressed or allowed for. So
> yes the amount of memory does effect how much ran you have left over. When i
> had a cheap 7600GS video card with 256 mb ram, i had nearly 3.5 GB ram on my
> Windows XP Asus Commando motherboard. Once i went to a 8800GTS 640MB unit, i
> only have 3 GB

For the last time: Video memory sizes have nothing to do with how much
memory your system sees.

YES there are I/O mapping concerns, NO they do not matter due to
remapping techniques.

Do not bring shared memory into the equation, I'm talking about local
memory. Here's a link that just happened to get writ today discussing this:

http://www.tomshardware.com/2008/02/15/vista_workshop/index.html

"Thanks to a technique called memory remapping, it is possible to move
around parts of the system memory in such a way that the full 4 GB is
still available for use. The trouble is that this feature had to be
deactivated in Windows Vista due to compatibility issues"

Mr.E Solved! · Joined: 22 Aug 2007 Posts: 497

DRS wrote:
> "Mr.E Solved!" wrote in message
> @comcast.com
>
> [...]
>
>> For the last time: Video memory sizes have nothing to do with how much
>> memory your system sees.
>>
>> YES there are I/O mapping concerns, NO they do not matter due to
>> remapping techniques.
>>
>> Do not bring shared memory into the equation, I'm talking about local
>> memory. Here's a link that just happened to get writ today discussing
>> this:
>> http://www.tomshardware.com/2008/02/15/vista_workshop/index.html
>>
>> "Thanks to a technique called memory remapping, it is possible to move
>> around parts of the system memory in such a way that the full 4 GB is
>> still available for use. The trouble is that this feature had to be
>> deactivated in Windows Vista due to compatibility issues"
>
> As has already been pointed out in this thread, remapping only works if both
> the motherboard and OS support it. XP, for example, does not, so the size
> of the video memory very much affects the amount of memory your system sees.
>
>

Yes it does, by design in Win XP x64, and by combination of luck and
design in 32-bit Windows XP Pro.