December 21, 2004
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Testbed configuration:
Software:
We shall use abbreviations in the diagrams for short: "int.video" for cases when integrated video accesses RAM using the UMA mode and "HyperMemory" for cases when integrated frame buffer is used on motherboards (certainly motherboards are also tested with enabled integrated video in the latter case).
Low level analysis of memory speed using RightMark Memory Analyzer (developed by our programmers) answers a lot of questions. There exists some formal difference between the chipsets, but it would be more correct to say that this difference exists between the motherboards (BIOS settings result in minor gains/losses in performance amplified by slight differences in FSB/CPU frequencies). In fact this single test is enough to acknowledge identical performance of the chipsets, but we shall carry out an extensive analysis anyway.
The situation with integrated video is more interesting. The use of UMA slightly decreases the system performance, but dedicated memory (even of a small capacity) in an integrated video accelerator nullifies this performance drop. It's a wonderful result, literally, taking into account that motherboard manufacturers will probably equip their models with frame buffer memory!
Two archivers configured for maximum compression are perhaps the example of applications, which are most critical to memory performance. As you can see here, even with enabled integrated video, ATi Xpress 200/P is practically no different from the VIA chipset. Several more tests to go:
There is no need in comments. These popular media encoders and converters demonstrate only insignificant performance fluctuations in tested systems depending on the real CPU frequency, and the same memory controller in all cases (because it's in the common element of these systems – Athlon 64 3500+ CPU) demonstrates the same performance.
Taking into account the above results, two questions remain vital for the game performance analysis: comparison of VIA K8T800 Pro and ATi Xpress 200P and the difference between memory access modes in the ATi chipset in case of enabled integrated video. In the first case we are interested in the battle of video interfaces rather than in the operating speed with memory (we have already acknowledged it to be the same): ATi Xpress 200 being the first representative of chipsets with PCI Express x16 [in our lab]. In the second case the obvious advantage of the mode with local frame buffer potentially gets balanced by the frame buffer size limit allocated in the main RAM: as ATi recommends, in this mode the UMA buffer size must match the size of the local one (while in the "pure" UMA mode you can allocate up to 128 MB).
Doom 3 demonstrates parity in both pairs compared, with a tiny advantage of ATi Xpress 200/PCIEx16 over VIA K8T800 Pro/AGP 8x. (Remember that the video cards we used for different interfaces are equalized in their frequencies, but the AGP model potentially profits from the lack of an interface bridge [on the card itself].)
The results are more interesting in several FarCry demos (there is some difference between them but the overall picture remains the same): in maximum simplified game modes PCIEx16 and AGP 8x demonstrate parity (also with a slight advantage of the former), but as the video settings get more complex, the AGP modification unexpectedly gains obvious advantage. The same tendency is in the UMA/HyperMemory pair: approximate parity and even slight advantage of the local frame buffer access in the tests with the lowest settings, but the large UMA buffer is an obvious leader when you switch to high resolutions and enable "bells and whistles".
However, Unreal Tournament 2004 always prefers the HyperMemory mode for a change. As a result, the only possible conclusion on the game tests – everything is up to a given game and even a given scene.
When we get hold of production samples of motherboards on Xpress 200, we shall perform additional tests of their integrated video to find their degree of performance conformity to external video cards on X300. Then we'll talk about the use of such video accelerators in modern games. As for now, you can make your own preliminary conclusions by absolute figures demonstrated by Xpress 200, taking into account that the minimum quality mode in 640x480 is purely synthetic, it's not interesting to play in this mode.
ATi managed to create a fast (in other words – not slower than competitors) chipset supporting almost all modern functions. PCIEx16 is not a preferable replacement for AGP 8x, but there is almost no difference for the new systems, while PCIEx1 support is a great advantage of Xpress 200/P for the future. Thus, a motherboard on Xpress 200P is a good if not the best (for the present moment) option for those who are going to buy a new computer with a 64-bit AMD processor. What concerns Xpress 200, this chipset has no competitors: if you want integrated video (for which you won't have to pay by a performance drop), which can at the very least allow you to play games, even if not 2004 hits, then your choice is obvious. We congratulate ATi and look forward to the production samples!
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Sergei Pikalov (peek@ixbt.com) December 21, 2004 |