ABSOLUTELY NOT!!
The PCI based video card (NOT PCI EXPRESS) is 1/4 to 1/32 the speed of an AGP based video card of the same chipset, in pure transfer bandwidth terms. All those texture transfers in game will go through a narrow bottleneck at the PCI bus interface.
If AGPx8 is a 4 lane highway, then PCI bus (not EXPRESS) is a stop sign on a dirt road. If a LOT of traffic has to drive on one or the other, which one will you pick?
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Also, the ATI 9250 is DirectX 8.1, not 9.0c, for hardware acceleration support. This means it has exactly the same limitations in performance as the Nvidia FX 5xxx series, and if your existing video is AGP based, it will at least transfer data to the card at many times faster than if the card sits on PCI bus.
---- and for the inevitable flamer who isn't satisfied yet ---
I was a PCI bus engineer for some years, but to spare you the several pages of tutorials, the short answer:
PCI-Express is considerably cheaper to lay-out than AGP, but considerably more expensive to test. Thus, big card companies can make identical to 50% faster bus transfer video cards on roughly 15 to 25 % less budget. But only very new motherboards have a PCI-Express connector.
Here's a good mini-tutorial on AGP:
http://www.interfacebus.com/Design_Connector_AGP.html
except the AGPx4 and AGPx8 clock is actually half the listed speed but DDR so reads are two times per physical clock cycle.
PCI is typically 33 Mhz, 32-bit and keyed for 5V signaling.
The high voltage means a longer delay in rise and fall of the signals, which limits everything from overclocking the PCI bus to the amount of energy needed to switch from a high (1)(>2.6V) to a low (0)(<0.6V) signal. Although PCI can be 3.3V, most motherboards are 5V keyed so that really old PCI cards can work; Intel now supplies only low voltage PCI, which is OK, and for PCI 66 Mhz and PCI-X the voltage is lower.
PCI-X is seen on server class motherboards, and allows PCI read commands to be answered without a performance delay, unlike the older PCI standard. From a signalling perspective, PCI-X adds 66, 100, and 133 Mhz transfers, but from a video card perspective PCI bus is much slower than just the bandwidth.
Instead, when a video card wants to read changes to the screen that don't come from internal texture RAM on the card, but rather from your PC OS+programs, these are PCI READ commands, and they can take a very long time to finish. So what happens is they place a read request, hang up as it were, then wait a little while and retry their read, hoping the data is now ready at the target region which they read from. Even reads from system memory are NOT handled immediately, but rather they are performed using the motherboard chipset, first at the south bridge for older PCs, then to the Northbridge, then across the front side bus, to the memory controller, to the DIMM module, then back across the FSB, then to the North Bridge, then to the South Bridge, now PCI can have the read answered.
Instead, AGP places a request directly at the north bridge, across FSB, to memory controller, back across FSB, and pulls the data. The data is pulled 8 to 32 times faster from a bandwidth perspective, but theres no protocol negotiation delay in placing the request, unlike PCI.
PCI Express offers a low pin count layout using 1,4,8, or 16 bits of data sent in parallel at 800Mhz or 1.6 Ghz clock frequency using low voltage differential signalling, for noise purposes, and employing LVDS buffers, transceiver, and receiver circuits. LVDS has been used for some years in laser printers and for laptop display cables, but it is expensive to work at 800-1600 Mhz frequencies. With PCI-E x16 (16 bits sent across 16 lanes at 800 Mhz), bandwidth is better than AGPx8.
From a protocol standpoint the software uses PCI-X style commands, allowing shorter development time, but the resaources to debug with a logic analyzer and oscilloscope are vastly higher. I have some memories of this :)
Anyway, I retired, sort-of, and emigrated to Bulgaria, but I hate to see you waste money because of poor knowledge. Enjoy the savings, and the game.
Glenn Sanders
glennushka@mail.bg