radeon 7500 vs 8500 video quality

[Ric]

Hi,

I recently decided to try a dual video card solution for 2 monitors rather
than having both connected to my 8500 AGP. I found there was a lot of
interference to the secondary monitor on the 8500 and it wouldn't take
custom resolution settings from Powerstrip. So I added a Powercolor Radeon
7500 PCI card and it solved those problems. I was also surprised that
suddenly my PVR application (WinDVR) can now record or timeshift at any
setting without losing audio sync. I guess the dual display mode on the 8500
made that harder for some reason...

On the downside, it seems like text on the 7500 is a little fuzzier than it
was on the 8500. Obviously there's a huge difference in 3D performance, but
I assumed the RAMDAC wouldn't have changed much from the 7500 to the 8500.
Is this incorrect? Is this a model specific issue, a PCI issue, or a
Powercolor vs. ATI issue? (My 8500 is an ATI.)

Thanks,
Ric

 

[Thomas]

On the downside, it seems like text on the 7500 is a little fuzzier
than it was on the 8500. Obviously there's a huge difference in 3D
performance, but I assumed the RAMDAC wouldn't have changed much from
the 7500 to the 8500. Is this incorrect? Is this a model specific
issue, a PCI issue, or a Powercolor vs. ATI issue? (My 8500 is an
ATI.)

I *think* the 7500 uses more on-board functions, while the 8500 has on-chip
functions. This means that all the filters and stuff are 'guaranteed'
quality for the 8500, whereas in the case of the 7500, you have to be lucky
the manufacturer didnt save too much money by using shitty equipment, like
the filters. And i have heard that Powercolor has a bad rep on that point...

Thomas

 

[Andy Cunningham]

I don't think the 8500 has anything more 'on-chip' which is 'onboard' on the
7500 - the hardware features missing on the 7500 merely go through the CPU
instead.

However the quality of the electronics going from the framebuffers to the
monitor connections are likely to vary across cards and brands. I have a
Powercolor 9000 Pro, and the image quality I think is slightly worse than on
my original ATi Radeon 64MB VIVO.

 

[Ric]

Wish I had thought to ask before buying. Would have shelled out the extra
bucks on the ATI card for a crisper display. Oh well... At least things are
working smoothly...

Ric

 

[Ric]

Another question: how does the OS (XP) and applications deal with hardware
enhanced features when there are 2 video cards. If I move a window between
displays, will it still use all the hardware features of the other hard?
What happens with a window that split between both displays?

Thanks,
Ric

 

[pjp]

I run two video cards, Radeon and Xpert. I think you'll find there's
limitations using both hardware overlay (video uses this) and directx (dx
normally only uses primary display). OpenGl more or less demands
dual-monitors be disabled regardless of how it's done although I think
Matrox may have this problem worked out with their latest.

 

[Ric]

So, for example, I use an application for 3D viewing of molecules which uses
OpenGL for 3D rendering. The program runs in a window, not full screen. If I
drag the window from the primary to the secondary adapter it loses hardware
acceleration? Does having the second display in any way adversely affect the
acceleration on the primary display?

I've been playing with having the transparency effect of hydravision turned
on and transparent windows definitely move faster on the 8500 driven monitor
than on the 7500 driven monitor (although even on the 8500 it seems a little
slow). If I have a window split between the 2 and move it up and down the
7500 half lags behind the 8500 half. Overlay, on the other hand, doesn't
seem to work on both monitors at the same time. I can drag an overlay window
to either one and it works, but if it's split, I only see the overlay on the
monitor where the majority of the window resides. The part of the window on
the other monitor only shows black.

Thanks,
Ric

 

[pjp]

Your reply tells me feature set is very card and os specific

I never run OpenGl programs in a window but know every one of them I have
including Quake III Arena and the like simply terminate back to my desktop
if I don't first disable secondary display(s). Same thing when I had my
prior Matrox G550 running in "dual-head" mode.

I would assume that when your OpenGl window gets dragged onto the 2nd
display it's running software mode but ... who knows or how to determine
same for sure I can't tell you???

My biggest problem is Xpert's driver doesn't "notice" the Radeon's VIVO
features and hence some options "disappear" from the display's custom dialog
boxs, e.g. specifically I loose the dialog with the TV OUT enable-disable
button. I have easy work arounds for it.

Wether or not I can watch accelerated video on the second display or
spanning across both seems very software player specific. Some do it, some
don't for me. Note in my case it's a 19" primary (at 1280x1024) and a 15"
secondary (at 1024x768) and most of the time the 2nd display only has
toolbars and or download status boxes and the like on it so I haven't done
extensive testing.

 

[Ric]

Your reply tells me feature set is very card and os specific

I never run OpenGl programs in a window but know every one of them I have
including Quake III Arena and the like simply terminate back to my desktop
if I don't first disable secondary display(s). Same thing when I had my
prior Matrox G550 running in "dual-head" mode.

I would assume that when your OpenGl window gets dragged onto the 2nd
display it's running software mode but ... who knows or how to determine
same for sure I can't tell you???

Well, I experimented a bit loading a large molecule into the viewer and on
the primary display rotating it is much faster than on the secondary
display. Hard to tell if that's because the 7500 is much slower than the
8500 or if it's software mode. However, with the window split between both
monitors the rotation speed on both monitors was the same, and the same as
if the window was fully on the secondary display, so I'm guessing that if
any part of the window is on the secondary display the program switches to
software only rendering, and if the window is fully in the primary display
hardware acceleration kicks in.
Not that this is a big deal. I don't really have any need for 3d
acceleration on the secondary display, which I use only for 2D applications
and video (although a dual display game would be pretty cool. In fact, with
my 2 card setup now, I could have 4 monitors going for a full emersive
experience...)

My biggest problem is Xpert's driver doesn't "notice" the Radeon's VIVO
features and hence some options "disappear" from the display's custom dialog
boxs, e.g. specifically I loose the dialog with the TV OUT enable-disable
button. I have easy work arounds for it.

Wether or not I can watch accelerated video on the second display or
spanning across both seems very software player specific. Some do it, some
don't for me. Note in my case it's a 19" primary (at 1280x1024) and a 15"
secondary (at 1024x768) and most of the time the 2nd display only has
toolbars and or download status boxes and the like on it so I haven't done
extensive testing.

I've got a 19 and a 22. There another 19 sitting in the next room that I
just sold. I've been fighting the temptation to stick the spare 19 on the
other side of my 22, giving up what's left of the meager desk space. I do
use the 19 for video or TV frequently while doing other work on the 22, so
the video acceleration there is nice to have. From what I can tell, overlay
is one or the other but you can move a window between the 2 and the overlay
will follow. I think when you can split the window between the 2 overlay is
not being used. Some applications, though will only seem to output to the
primary display. I may yet set up an old 15" I have lying around as a 3rd
display purely as a video monitor. I wonder if I'd damage anything by having
it sit on top of one of the other monitors? My VCR currently lives on top of
my 22, which I think is somewhat precarious in that the 22 seems to vent a
lot of heat from the top grill, which is probably slowly cooking the back
end of my VCR. Whenever I've had to pull cables from the back the metal is
pretty warm... Mind you, between DVD and DVR I don't really use tape much
anymore. Still, I find my VCR's tuner does a better job than my TV Wonder.

Ric