Do PCI Video cards REALLY suck that bad?

[phaxmohdem]

Alright, I've got this Compaq AP400 Dual PIII 600 Box that I use as the control node for my Lightwave render farm at home. Every now and again I have to use it to tweak a 3D object or scene real quick before final rendering, and I've been trying to find ways to speed up the UI in Lightwave while doing this on a slower machine.

Originally the machine ahd an AGP Matrox card (4MB I think) Which I promptly threw out and replaced with a PCI Radeon 7000 w/ 64MB DDR RAM.

Today however I wanted to see how an AGP card would do in this system, so I removed the ATI card, and the only AGP card I had at home that would fit in the older AGP socket of this system was a Matrox G450 Dual Head card w/ 16MB RAM,(my ATI 9600SE Wasn't socket compatible due to voltage requirements I'm guessing) so thats what I put in. I figured that it would suck, but it is actually 200-300% faster than the ATI card was in lightwave.

WTF? Do PCI cards really suck that bad? Is it just the system architecture of this particular box slowing things down? I realize that there's more bandwidth to play with, in AGP, but if thats the case and a Radeon 7000 is bandwidth limited on the PCI bus why on earth are there FX5200's/5500's and such for PCI. Can anybody shed light on this?

Summary:
Matrox G450 Dualhead 16MB AGP =="Bad ass"
ATI Radeon 7000 64MB PCI =="Pwn3d"

 

[ProviaFan]

Other than a basic understanding of the shared nature and limited bandwidth, I have no other idea why PCI video cards are so freaking slow, but I had an experience that was very similar to yours.

 

[hooflung]

That is why it is so freaking slow. Two IDE channels, Onboard/Add-on Sound, Serial ATA, USB, Firewire, Parallel port, Serial Ports, Keyboard, PS/2 mouse all use the PCI-Bus. Some computers might be better off than others, read as they might turn off a lot of stuff or not use it, but the fact is PCI is out dated.

 

[Peter]

None of what you're listing uses the PCI bus in a modern PC, except for Firewire. Everything else is integrated into the chipset, and off the PCI bus. That old PIII box still might, though.

PCI graphics cards are inherently slow because (1) the power budget is lower than on AGP and (2) the most recent AGP chips aren't electrically compatible with PCI anymore, so we're stuck with older gear.

The Radeon-7000 was made to provide for cheap dualhead solutions. Call it deliberately slow if you please - put the same thing on AGP and see how it's no faster either.

 

[phaxmohdem]

Originally posted by: Peter

The Radeon-7000 was made to provide for cheap dualhead solutions. Call it deliberately slow if you please - put the same thing on AGP and see how it's no faster either.

This is pretty much true. I also had an AGP version of the 7000 at one point (32MB Dual head). Granted I can't test it in this particular system, but one weekend a year or so ago I went through and benched every video card in my possesion just for fun in an old AThlon XP test rig, and the 7000 series cards were all anemic at the bottom of the list (the matrox cards I had then 16MB G450 and 32MBG550 were about the same performance as the radeons in the benches actually)

If I remember right the AGP 7000 just edged out the PCI versions but not enough to call it a decisive victory.

I still remember when I thought VLB ws the shiznat, PCI nothing that was a pipe dream for me. Now its this generations ISA bus.

 

[WhipperSnapper]

Back in Feb 2001 I picked up a new HP Vectra (P3 533) off of the uBid auctions that came with a 32 MB Matrox G400 (AGP). It's played all of the games that I could reasonably expect to play just fine for the most part as long as other programs were off. It's my UT 1999 card. Overall I'd say it's been pretty solid and I suppose I've been pretty happy with it.

 

[Auric]

As bad as Matrox is, the chips are just too disparate to draw comparisions aboot the interfaces but obviously PC PCI is 33 Mhz and AGP is 66 Mhz. The 7000 is a cut-down 64-bit chip for basic 2D. Compare the G450 AGP to a 8500 PCI and you will see what a proper old 3D core sans memory bandwidth limit will do despite the bus frequency limit.