Possible performance slowdown when adding a second G450?

[shanebrooks]

I have used dualhead on a G450 for ages (WinXP SP2)

I just added a G450 PCI and added a third monitor.

Qualitatively - I am now seeing poorer performance of the desktop. Windows sometimes "tear" as they are drawn and I have this sense that windows even open slower. It is as if the redrawing of the desktop is noticably slower.

Is it possible that adding the PCI card has slowed desktop refreshes?

Would a P750 fix all this or is it all in my head

Machine is a dual AMD 2400+ with 2 gigs of ram so it has horses to spare. I do know the AMD chipset struggles with bandwidth on the 32bit PCI bus... but the PCI G450 is only drawing one screen in 2D at 1280x1024

I never use 3d graphics and the G450 has been great so far. (Ok I have been known to swap the G450 for an ATI card to play a game or two but image quality always makes me swap back!)

[Wombat]

Shane! Good to see you out man.

One thing to remember is that a G450 PCI in a non-Intel chipset mean no bus-mastering.

[shanebrooks]

I didnt know that. And I suppose that assigning an IRQ to each video card in the bios wont help either (just reading the context help for the bus mastering checkbox in the latest G450 drivers and it suggests Direct3D needs an IRQ for busmastering to work).

I can say performance is bad. For example, the standard OpenGL screensavers that come with windows are full of jerky movement even with the resolutions cranked back (pipes, 3Dtext, flowerbox). These only smooth out when made very small and low res. Seems poor for dual 2400+ even given the G450's 3D limitations.

[rylan]

Yeah its a problem with the cards fighting for bandwidth on the bus. sucks huh
I always thought the G450/G550 were pos cards.

[shanebrooks]

Will replacing the two G450s with a P750 clear the bus problems as its all going through the AGP or does it just create another bottleneck?

I gather image quality is the same as the G450's so at worse I'd be buying back a PCI slot

...dont really like the idea of having to install .Net just for the video drivers though.

[rylan]

I would think it should solve the issue with a P750.

[shanebrooks]

Well wholey moley batman these things cost a mint and then some here!!

I'm officially in the market for a used P750 and posted a "wanted to buy" in the for sale forum.

</end shameless plug>

[rylan]

Oh yeah, forgot to mention the pricetag

[shanebrooks]

Problem solved using the trusty wallet method.

I'm buying K6-III's old Parhelia

My G450 will live on in my backup server - gotta love that fanless card!