Forcing refreshrate on Intel i810 chipset


P

Patrick Vervoorn

I have a somewhat older system here, containing an Intel i810 chipset. I'm
running Windows XP Pro on it, and it's connected to a IIyama VisionMaster
Pro 510 CRT.

Whatever I do, cannot seem to force the i810 to set itself to
1280x1024x85Hz, while that should be possible according to:

http://www.intel.com/support/graphics/intel810/sb/cs-009122.htm

All I get is 75Hz max, which causes a flickery sensation in my peripheral
vision.

I've installed the latest drivers from intel, which were a bit older than
the stuff pre-installed with XP, but which did add an i810-specific
section to the display driver properties tab.

When I select 85Hz there, the resolution automatically falls back to
1152x864. Also by going to 16-bit mode, while staying at 1280x1024, I
still cannot select 85Hz.

I've also tried changing the monitor from the Vision Master 510 to Plug
'n' Play, and also something completely else, but that also doesn't allow
the 85Hz mode to appear.

Any other way I can force the hardware to select 85Hz?

It's an HP VL400 system, but due to some connection issues with my ISP I
can't seem to reach HP's website at the moment, so I can't check there
whether the specs of the VL400 prohibit it displaying 1280x1024@85Hz,
unfortunately...

Regards,

Patrick.
 
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E

Eric Gisin

The max dot clock will be limited by the DRAM timing (and perhaps FSB).
 
P

Patrick Vervoorn

The max dot clock will be limited by the DRAM timing (and perhaps FSB).
I think, but I'd have to check to be sure, the machine in question already
contains the fastest RAM it can take: PC133 memory.

Is there any way to check whether it's the current DRAM timing which
limits the available refreshrate?

Regards,

Patrick.
 
P

Patrick Vervoorn

[Snip]
It's an HP VL400 system, but due to some connection issues with my ISP I
can't seem to reach HP's website at the moment, so I can't check there
whether the specs of the VL400 prohibit it displaying 1280x1024@85Hz,
unfortunately...
I know this is usually 'not-done' but I finally got access to HP's
website, and after some searching found the verbose technical docs about
the VL400. In this document HP themselves also claim the on-board graphics
can do 1280x1024 @ 85Hz, even in True-Color mode. (Unless they brainlessly
copied the table from the Intel documentation).

I still have no idea why I can only go up to 75Hz in this mode, but I'll
open up the system and physically check the type of memory installed, to
see if that's the problem...

Regards,

Patrick.
 
B

Bob Knowlden

A stupid question:

Does your *monitor* support 85 Hz at 1280X1024?

Address scrambled. Replace nkbob with bobkn.

Patrick Vervoorn said:
[Snip]
It's an HP VL400 system, but due to some connection issues with my ISP I
can't seem to reach HP's website at the moment, so I can't check there
whether the specs of the VL400 prohibit it displaying 1280x1024@85Hz,
unfortunately...
I know this is usually 'not-done' but I finally got access to HP's
website, and after some searching found the verbose technical docs about
the VL400. In this document HP themselves also claim the on-board graphics
can do 1280x1024 @ 85Hz, even in True-Color mode. (Unless they brainlessly
copied the table from the Intel documentation).

I still have no idea why I can only go up to 75Hz in this mode, but I'll
open up the system and physically check the type of memory installed, to
see if that's the problem...

Regards,

Patrick.
 
P

Patrick Vervoorn

A stupid question:

Does your *monitor* support 85 Hz at 1280X1024?
Yes. It supports up to 100Hz @ 1280x1024, and I'm running a second system
(with a Matrox Millennium) on that monitor, which does 1280x1024 @ 85Hz
just fine. That image looks rock solid, no 'flickinger' in my peripheral
vision there...

Regards,

Patrick.
 
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P

Patrick Vervoorn

[snip]
Whatever I do, cannot seem to force the i810 to set itself to
1280x1024x85Hz, while that should be possible according to:
[more snippage]

Amazingly, I finally solved this by checking the BIOS; the preferences for
the 'primary' video device were set to 'PCI' (there is no PCI videocard in
the system). When I set it to the other possible setting ('AGP/on-board
video') and rebooted, the Intel i815 driver settings utility suddenly
allowed me to select 85Hz at 1280x1024, and even higher refreshrates
(100Hz) for the lower resolutions (which were previously capped around the
85Hz mark).

Why the designers made the system to boot up like this, instead of beeping
to me it didn't contain a PCI videocard, I don't understand... :(

Anyway, desktop runs at 1280x1024@85Hz, I don't notice any flickering
anymore in my peripheral vision, so for now I'm happy.

Regards, Patrick.
 
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P

Patrick Vervoorn

[snip]
Whatever I do, cannot seem to force the i810 to set itself to
1280x1024x85Hz, while that should be possible according to:
[more snippage]

Amazingly, I finally solved this by checking the BIOS; the preferences for
the 'primary' video device were set to 'PCI' (there is no PCI videocard in
the system). When I set it to the other possible setting ('AGP/on-board
video') and rebooted, the Intel i815 driver settings utility suddenly
allowed me to select 85Hz at 1280x1024, and even higher refreshrates
(100Hz) for the lower resolutions (which were previously capped around the
85Hz mark).

Why the designers made the system to boot up like this, instead of beeping
to me it didn't contain a PCI videocard, I don't understand... :(

Anyway, desktop runs at 1280x1024@85Hz, I don't notice any flickering
anymore in my peripheral vision, so for now I'm happy.
Darn, it seems I shouted 'Eureka' too early. After a reboot, I was back in
the old situation: the refreshrate properties only went up to 75Hz again
for 1280x1024. Since then I've also 'switched the PC vs AGP/On-board BIOS
setting around with no effects, so it _could_ be a coincidence that after
changing that setting the problem was (temporarily) solved.

It seems the boot where I could select 1280x1024@85Hz was some kind of
one-in-a-million fluke, whereby the chipset came up somewhat differently.
(Pure speculation on my part.) I have no idea how to force this though. I
played around with an i815 'tweak' utility, but evertime I change one of
the memory access settings, the machine crashes/reboots immediately, so
that doesn't really help.

The frustrating part is: I know the machine can do it, since it came up
once with the ability to select 85Hz instead of 75Hz (and ran fine doing
that). I'm baffled. If anyone has any other ideas, I'd be much obliged.

Regards,

Patrick.
 

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