ULi M1695 (M1567 southbridge) chipset and AGP question

[pigdos]

I've noticed that for the one motherboard (Asrock) that uses this chipset
that AGP benchmarks are noticeably slower than PCIe (for the same graphics
card in AGP/PCIe flavors). Could the fact AGP is running off the southbridge
(at least according to the ULI documentation) have something to do with
this?

Why didn't ULI just hang AGP off of the Northbridge (M1695)? Wouldn't this
make more sense?

 

[Garrot]

I've noticed that for the one motherboard (Asrock) that uses this chipset
that AGP benchmarks are noticeably slower than PCIe (for the same graphics
card in AGP/PCIe flavors). Could the fact AGP is running off the southbridge
(at least according to the ULI documentation) have something to do with
this?

Show me the benchmarks, any review I've read of this motherboard doesn't
say that at all. Quite the opposite in fact. I have this mb but I use
PCI-E graphics card on it now.

 

[pigdos]

Here's the link: http://www.anandtech.com/mb/showdoc.aspx?i=2524&p=9 .

 

[Garrot]

Here's the link: http://www.anandtech.com/mb/showdoc.aspx?i=2524&p=9 .

I don't know how you infer the from that article that the AGP performance
is sub-par. In fact, it is the only mb with both AGP and PCI-E that has
good AGP performance. From the article you posted, which I have already
read a long time ago.

"It is clear, after our testing of both ULi Reference and ASRock boards,
that the ULi M1695/M1567 is capable of both top AGP performance and top
PCIe performance."

 

[Yousuf Khan]

I don't know how you infer the from that article that the AGP performance
is sub-par. In fact, it is the only mb with both AGP and PCI-E that has
good AGP performance. From the article you posted, which I have already
read a long time ago.

"It is clear, after our testing of both ULi Reference and ASRock boards,
that the ULi M1695/M1567 is capable of both top AGP performance and top
PCIe performance."

Now does this board have a real AGP connector, or one of those AGP-PCIe
bridge type things?

BTW, I just picked up a AGP video card for my old Athlon XP system, it's
an ATI X1600Pro chipset w/ 512MB of memory (that's exactly half as much
as my main system RAM actually), so it's a mid-end card. I was thinking
of upgrading towards an PCIe system, but that would've meant not just
motherboard, but CPU, memory, possibly hard drives and optical drives as
well would've needed to be replaced. That was approaching $1000 in the
Intel direction and $800 even in the AMD direction, so I said screw it,
I just need to play one specific game. Is there any difference between
AGP and PCIe performance for these mid-range video cards?

Yousuf Khan

 

[pigdos]

Point taken, a 10 FPS drop in framerate when using AGP isn't huge, but EVERY
title tested showed a measurable drop in framerate when using AGP cards as
opposed to PCIe. It would be interesting to see what the framerate drop
would be for something like FEAR as opposed to the older titles they were
testing with in the article.

 

[pigdos]

I don't think it has an AGP-PCIe bridge because while the PCIe bus is hung
off the northbridge (MCH?), AGP is hung off the southbridge.

 

[Tony Hill]

I've noticed that for the one motherboard (Asrock) that uses this chipset
that AGP benchmarks are noticeably slower than PCIe (for the same graphics
card in AGP/PCIe flavors). Could the fact AGP is running off the southbridge
(at least according to the ULI documentation) have something to do with
this?

Tough to say because I haven't seen a specific review of the ASRock
board. However the extra step of going to the AGP vs. PCI-E should
reduce performance by a bit. I've seen some reviews of the reference
board which showed about a 5% performance hit on video intensive
applications, which is about what I would expect. If you're seeing
more like a 20% performance hit than chances are it's a BIOS problem
or something specific to the individual board.

Why didn't ULI just hang AGP off of the Northbridge (M1695)? Wouldn't this
make more sense?

From a performance standpoint, yes. From a pin-count and cost point
of view, probably not. Most of these chipsets are likely to be sold
as bottom-of-the-barrel devices, so cost reduction is FAR more
important than improving performance.

 

[Garrot]

BTW, I just picked up a AGP video card for my old Athlon XP system, it's
an ATI X1600Pro chipset w/ 512MB of memory (that's exactly half as much as
my main system RAM actually), so it's a mid-end card. I was thinking of
upgrading towards an PCIe system, but that would've meant not just
motherboard, but CPU, memory, possibly hard drives and optical drives as
well would've needed to be replaced. That was approaching $1000 in the
Intel direction and $800 even in the AMD direction, so I said screw it, I
just need to play one specific game. Is there any difference between AGP
and PCIe performance for these mid-range video cards?

Yousuf Khan

I used an X800XL on this mb for quite some time and performance was
decent. I'm not using the same mb with a 7900GT PCI-E card.