PCI Vs AGP

[Chris]

Hi,

I bought a piece of junk pc, but it was only $25 for a celeron
2.66 ghz with dvd burner, 512mb ram, card reader for every known card
120gb hard disk (turned out to be 40 though), all in all a great deal.
Like I said it's a POS computer by emachines with integrated video
with an intel 82845G pci video with 8mb shared memory. I'm not really
into 3d games too much but like to play once in a while. I would like
to replace the POS on board video, but without AGP. Now, I have
somewhere in my possession a 16mb banshee video card which I'm pretty
sure is PCI (I don't know where it is at the moment) and I am
considering a low end replacement. MY choices are:
The banshee card (if it's pci) FREE
I can't find any comparisons between the banshee and the onboard
video. Would the banshee be faster? A LOT?

A geforce 4 mx 400 series pci 64mb $34
a Raidon 9250 PCI 128mb card $50

Would these low-end cards be hampered by the PCI bus instead of AGP?
I was under the impression that the biggest advantage of an AGP card
is for storing textures in main system ram and then having a high
speed data path between the card and system ram. With today's large
amounts of memory on board the card, that would seem to be a moot
point. In any event, I'm assuming that in order for the PCI bus to
become the bottleneck you would need a fast really fast video card and
that the above mentioned chips would have almost no increase in AGP
over PCI, while still being SUBSTANTIALLY faster than what is on board
(the intel ). Any advise would be appreciated.

Chris


If life seems jolly rotten
There's spmething you've forgotten
and thats to laugh and smile and dance and sing!

 

[Arno Wagner]

Hi,

I bought a piece of junk pc, but it was only $25 for a celeron
2.66 ghz with dvd burner, 512mb ram, card reader for every known card
120gb hard disk (turned out to be 40 though), all in all a great deal.
Like I said it's a POS computer by emachines with integrated video
with an intel 82845G pci video with 8mb shared memory. I'm not really
into 3d games too much but like to play once in a while. I would like
to replace the POS on board video, but without AGP. Now, I have
somewhere in my possession a 16mb banshee video card which I'm pretty
sure is PCI (I don't know where it is at the moment) and I am
considering a low end replacement. MY choices are:
The banshee card (if it's pci) FREE
I can't find any comparisons between the banshee and the onboard
video. Would the banshee be faster? A LOT?

A geforce 4 mx 400 series pci 64mb $34
a Raidon 9250 PCI 128mb card $50

Would these low-end cards be hampered by the PCI bus instead of AGP?
Yes.

I was under the impression that the biggest advantage of an AGP card
is for storing textures in main system ram and then having a high
speed data path between the card and system ram. With today's large
amounts of memory on board the card, that would seem to be a moot
point.

The amount of textures commonly used is larger than the amount of
memory on your cards (or most/all). So textures have to frequently be
moved into the card.

In any event, I'm assuming that in order for the PCI bus to
become the bottleneck you would need a fast really fast video card and
that the above mentioned chips would have almost no increase in AGP
over PCI, while still being SUBSTANTIALLY faster than what is on board
(the intel ). Any advise would be appreciated.

Depends on the games you want to play. WoW in 800x600 with miminal
details probably runns smooth. A current shooter is very likely a lost
cause, i.e. unplayable.

Arno

 

[Mike Ruskai]

Hi,

I bought a piece of junk pc, but it was only $25 for a celeron
2.66 ghz with dvd burner, 512mb ram, card reader for every known card
120gb hard disk (turned out to be 40 though), all in all a great deal.
Like I said it's a POS computer by emachines with integrated video
with an intel 82845G pci video with 8mb shared memory. I'm not really
into 3d games too much but like to play once in a while. I would like
to replace the POS on board video, but without AGP. Now, I have
somewhere in my possession a 16mb banshee video card which I'm pretty
sure is PCI (I don't know where it is at the moment) and I am
considering a low end replacement. MY choices are:
The banshee card (if it's pci) FREE
I can't find any comparisons between the banshee and the onboard
video. Would the banshee be faster? A LOT?

No. Despite the fact that the Intel chip is garbage, the Banshee is
so much older that it's only about half as fast.

A geforce 4 mx 400 series pci 64mb $34
a Raidon 9250 PCI 128mb card $50

A GeForce 4 MX 440 would be the faster of these choices. Roughly four
times as fast as the Intel chip.

Would these low-end cards be hampered by the PCI bus instead of AGP?
Absolutely.

I was under the impression that the biggest advantage of an AGP card
is for storing textures in main system ram and then having a high
speed data path between the card and system ram.

No, the biggest advantage is speed.

A standard 32-bit 33MHz PCI bus has a maximum throughput of 132MB/sec.
A 1X AGP slot has a maximum throughput of 266MB/sec. A 8X AGP slot
goes up to 2.1GB/sec.

A 1X PCIe slot has throughput of 250MB/sec, and scales linearly (i.e.
a 16X PCIe slot has a throughput of 4GB/sec).

With today's large
amounts of memory on board the card, that would seem to be a moot
point.

That's mostly true. In practice, only onboard AGP chips use shared
system memory for textures. Add-in cards carry their own texture
memory.

In any event, I'm assuming that in order for the PCI bus to
become the bottleneck you would need a fast really fast video card and
that the above mentioned chips would have almost no increase in AGP
over PCI, while still being SUBSTANTIALLY faster than what is on board
(the intel ). Any advise would be appreciated.

Well, now you know that assumption is incorrect. Maxing out the PCI
bus is trivial for a 3D graphics card to do.

If your system has an AGP slot, then getting an AGP card will be the
best choice, by far.

 

[DRS]

[...]

A standard 32-bit 33MHz PCI bus has a maximum throughput of 132MB/sec.
A 1X AGP slot has a maximum throughput of 266MB/sec. A 8X AGP slot
goes up to 2.1GB/sec.

A 1X PCIe slot has throughput of 250MB/sec, and scales linearly (i.e.
a 16X PCIe slot has a throughput of 4GB/sec).

To be strictly fair though, the real reason PCIe x16 has twice the bandwidth
of AGP X8 is that it's bidirectional whereas AGP isn't. That's great if
you're importing vast amounts of video but for gamers it's completely
irrelevant. The reality is that PCIe x16 gives gamers no noticeable
improvement over AGP X8 and a barely noticeable improvement over AGP X4.
PCIe was and is a solution in search of a problem.