Dokter Tom heeft een artikeltje gepost over problemen met de Apollo Pro 133A chipset. Deze blijkt met de nieuwe v4.20 AGP drivers duidelijk slechter te presteren als met de oude v4.17 drivers. De zogenaamde ATA66 support blijkt alleen op papier te bestaan: in benchmarks blijven transfers vanuit de harddisk cache rond de 30MB/s te steken terwijl de i820 en Promise ATA66 controller beide exact 49,5MB/s trekken:
Unfortunately our tests revealed that this support exists only on paper. Measuring the maximum throughput from the hard disk cache to the system produced results that were only in the area of ATA33 or UDMA33, which offers a bandwidth of only up to 33 MB/s. There's currently no real world benchmark that would make any difference, mainly because even the fastest disks can only supply up to 30 MB/s from the physical media, but this might change very soon. Therefore I expect VIA to sort out this issue as soon as possible. We do not know if the problem is due to a driver issue, or if the actual chipset is unable to transport data fast enough, but we do know that motherboards do report 'Multi word DMA Mode 4' with the proper hard drives, alas without offering the expected throughput.
Intel's i810, i810E, 820 and i840 chipsets claim UDMA66-support as well and they are actually able to reach the expected throughput. Alternatively we tested with the Promise Ultra66 PCI card, which is usually used for systems that don't offer ATA66-support. This card produced the same results as the motherboards with Intel 8XX chipsets.
Verder keek Tom ook nog naar de invloed van Cas 2 en Cas 3 PC133 SDRAM op de memory en AGP performance.