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Monday, August 01, 2005

PCI Express or AGP for Warcraft 3 Gaming?

The following are some anslysis of the AGP and PCI Express Video Card. I have read various such article before, and most of the review has proven that the latest technology does not mean is better than old technology, perhaps is only the way the manucturer to gain more on the profit margin.

Analysis: AGP on PCI Performance Penalty Likely Mis-Represented:
A true AGP-on-PCI solution is going to lack a GART driver and be limited to only 33 MHz of shared-bus PCI. In the majority of the tests moving from AGP .67 to AGP 1x and installing GART made the most difference out of any change. Any AGP-on-PCI solution on a standard PCI slot is going to be even more bandwidth limited (.5x AGP vs. our .67x) and hence, crippled from the start. The loss of GART is an additional performance whack that’ll hit performance far harder than 20%.
Even assuming motherboard manufacturers used an expensive, PCI-X solution, there’s still the problem of no GART and the fact that PCI-X is still a shared bus implementation. Using ANY 33-MHz PCI card on such a board would promptly prevent the PCI-X bus from running at its standard 66 MHz. A 33 MHz, 64-bit PCI-X-AGP card would have roughly AGP 1x bandwidth, and thus most games would be playable--but a considerable number of titles want 2x at a minimum to really see performance--and of course, there's the loss of GART.
Given the bandwidth chokepoint and lack of drivers we’d expect any AGP-on-standard-PCI solution to cut performance 50-70% in almost any game or professional application. Even UT2K3 will throttle downwards if AGP bandwidth is cut severely enough. AGP on PCI-X would offer more bandwidth and higher raw performance, but also packs its own penalties.
Bottom line? You’re probably going to be better off staying away. Far away. Very far.

Conclusion: PCI-Express on Desktop Likely to Offer Very Little Performance:
Is PCI-Express a bad idea? Not at all. It cuts manufacturing costs and simplifies trace design; from that perspective alone it’s a smart advance. But don’t confuse “smart advance” with “performance advantage.” Based on the numbers we’ve seen here, the average game and application (even the modern ones) typically do not take advantage of AGP 8x. None of our games showed more than a small increase. Professional applications are a different story, there we saw boosts of 30-40%. Its also been suggested that certain specified applications, like video editing, might run more smoothly over the PCI-Express system.
For the gamer, however, PCI-Express is going to be a non-issue. Given that most games today barely stress the AGP 2x bus, moving to double AGP 8x isn’t going to do anything. It’s the equivalent of widening a highway no one drives on. Had AGP developed in the direction it was intended to things might be different, but it didn’t. Now, to some extent, it’s a solution to a problem no one has.
If you’re still running on an original Athlon, P3, or Socket 423 P4, than a PCI-Express system might not be a bad idea, but if you’ve got something newer and aren’t using a specialized application demonstrated to gain from PCI-E, we wouldn’t bother planning to upgrade. You’ll just be throwing money away after hype. The reality is, in many cases we're barely pushing AGP 2x, sometimes 4x. 8x, despite now being two years old, is mostly hot air.

[article extrated from http://www.sudhian.com, original arthur by Joel Hruska.]