Just a little taste
Brandon's hard at work on a new chipset shootout article, but we're going to steal a little bit of his thunder and do a quick BX133 vs. 815 chipset comparison. We noticed in the comments section of our 815 motherboard round-up article that there was still a question about whether or not the 815 chipset is a suitable replacement for the BX.
It's been over two years, but the BX chipset is still alive and kicking. The chipset's longevity has been amazing. The chipset has lasted this long because it can still get the job done, far surpassing its original duties, but it also helps that Intel hasn't been able to release a suitable replacement yet. The 820 chipset never became a mainstream option because of RDRAM requirements (the memory translator hub is still good for a few laughs).
Intel only intended the BX chipset for the 66MHz and 100MHz FSB speeds, but the chipset's surprising stability on the 133MHz FSB has extended the BX chipset's lifespan considerably. AGP 2X and UDMA/33 support round out the rest of the BX's features.
The match up
The 815 chipset is Intel's newest challenge to the venerable BX chipset. The 815 offers official support for the 133MHz FSB, AGP 4X, and UDMA/66. The 815 chipset also has the ability to support UDMA/100 depending on the ICH (I/O controller hub) used. Intel doesn't officially support front side bus speeds above 100MHz on the BX.
The big question we have to answer is whether or not these weaknesses actually matter. Even without official Intel support, the BX seems to handle the 133MHz just fine in terms of CPU stability, but overclocking the bus will also result in an overclocked AGP bus which may have an affect on total system stability. Some video cards might not function on an overclocked bus. The 815 offers the additional 1/2 AGP clock dividers to prevent the unwanted overclocked bus side effects.
AGP 4X and UDMA/66 support may sound impressive, but we're not convinced that these new features offer much in real world performance increases. Today's video cards now feature 32MB and 64MB of onboard memory, greatly marginalizing the need for high AGP transfer speeds. UDMA/66/100 isn't that large of an issue since many BX motherboard manufacturers now add in third party UDMA/66/100 controllers to make up for the BX's deficiency.