VIA Chipsets slow down PCI cards
Benchmarks: Burst Mode
For these tests we used Maxtors DiamondMax D540X and D740X with the Promise- and Highpoint-controllers. The other components are listed in the "Test Setup" section, found to the right of this text.
To do some compatibility checks, we also ran the same set of tests with nine motherboards equipped with chipsets by Intel, VIA, ALi and SiS. As many boards feature the same PCI controllers, we only did some quick cross checks with other chipsets, e.g. VIAs KT266A that all showed the same behavior.
Motherboards with the Intel chipsets i815, i820 and i845 offered the PCI performance we expected. The Promise Ultra133 TX2 card with the Maxtor drives was able transfer between 109 and 117 MBytes/s. Even if one considers the overhead that's a very good result. Highpoints RocketRAID 133 still gives you 95 to 100 MBytes/s. Motherboards with SiS and ALi chipsets showed similar results.
Chipset | Highpoint RocketRAID 133, Maxtor D540X | Highpoint RocketRAID 133, Maxtor D740X | Promise Ultra133 TX2, Maxtor D540X | Promise Ultra133 TX2, Maxtor D740X |
---|---|---|---|---|
| ||||
ALi Alladin Pro5 | 95,0 MBytes/s | 95,9 MBytes/s | 96,3 MBytes/s | 96,1 MBytes/s |
Intel 815 | 96,0 MBytes/s | 97,6 MBytes/s | 113,0 MBytes/s | 115,2 MBytes/s |
Intel 820 | 94,9 MBytes/s | 95,4 MBytes/s | 108,9 MBytes/s | 114,9 MBytes/s |
Intel 845 | 97,6 MBytes/s | 100,5 MBytes/s | 114,5 MBytes/s | 117,4 MBytes/s |
SiS 645 | 94,2 MBytes/s | 96,7 MBytes/s | 107,1 MBytes/s | 108,0 MBytes/s |
VIA MVP3 | 74,1 MBytes/s | 76,6 MBytes/s | 63,8 MBytes/s | 63,5 MBytes/s |
VIA KT133A | 76,1 MBytes/s | 77,5 MBytes/s | 78,4 MBytes/s | 78,2 MBytes/s |
VIA P4X266A mit VT8233 | 79,7 MBytes/s | 81,2 MBytes/s | 90,3 MBytes/s | 90,1 MBytes/s |
VIA P4X266A, VT8233A | 64,8 MBytes/s | 62,6 MBytes/s | 72,3 MBytes/s | 72,6 MBytes/s |
As the table shows, burst performance significantly drops when these ATA/133 cards are plugged into a motherboard with VIAs chipsets. The Promise Ultra133 TX2 there only offers between 64 MBytes/s (VIA MVP3) and 90 MBytes/s at best (VIA P4X266A with VT8233 Southbridge). Highpoints PCI card shows similar effects. Even when the chip HPT372-Ultra is integrated with the motherboard as with the Shuttle part we used, there's no more than 65 MBytes/s tranferred. This motherboard is equipped with VIAs P4X266A chipset, including the VT8322 as a southbridge.
Please note: The burst transfers given here are completely independent from the CPU used and its clock speed. Even the slowest CPU we used, an AMD K6-2 at 400 MHz, has a much higher bandwidth than the bottlenecks named PCI or IDE bus.