VIA Chipsets slow down PCI cards
SCSI: Benchmarks
To not measure the performance of one single drive with our Quad-RAID-0 we set the block size to a multiple of 128 KBytes for the read tests. This guarantees that every one of the four hard drives is working as hard as possible during the benchmarks.
As every single drive delivers up to 54 MBytes/s transfers, the bandwidth of Adaptecs-RAID-2100S with Ultra160-SCSI is eaten up completely with this configuration already. To keep up the flow of data to and from the drives, the card features a cache of 32 MBytes. As a consequence, this RAID card is able to fully load the PCI bus in our setup.
We took the following scores using MSIs 845 Pro2 (845 chipset) and VIAs P4BX (P4X266A) motherboards with this same SCSI-RAID.
Intel 845 | VIA P4X266A | |
|---|---|---|
For all tests: Adaptec SCSI-RAID-2100S with four Fujitsu MAM3184MP, RAID-0 | ||
sequential reads max. | 113,6 MBytes/s | 72,9 MBytes/s |
sequential reads average | 110,9 MBytes/s | 72,3 MBytes/s |
sequential reads min. | 106,2 MBytes/s | 70,8 MBytes/s |
tecMark Read | 23,6 MBytes/s | 21,0 MBytes/s |
tecMark Write | 32,7 MBytes/s | 24,0 MBytes/s |
tecMark Copy | 31,4 MBytes/s | 25,7 MBytes/s |
copying a 2 GByte file | 101 Sekunden | 133 Sekunden |
With the MSI motherboard the RAID-0 sequentially reads data with up to 114 MBytes/s. This performance is maintained over nearly the whole capacity of the RAID: the minimum speed only drops to 106 MBytes/s. Even with burst transfers from the cards cache we found the same results.
This looks much worse with the VIA motherboard. Our RAID there only delivers a maximum of 72 MBytes/s with sequential reads. Although the system also sticks with this speed over almost the whole capacity, a lot of the potential of the RAID is wasted. To be more precise: If you spend more than 2300 Dollars for a RAID system like this, you loose 34 per cent of the performance when this RAID has to deal with a VIA chipset.
Even with everyday tasks the differences are shuttering. If you copy a file of 2 gigabytes on the RAID systems, the Intel solution finishes 30 per cent faster then a VIA motherboard.