nhattu1986 wrote on 2024-03-10, 11:40:
I think the DMA mode is depend on which bridge chip is on the adapter board
i have good result with JMicron JM20330 bridge
if your adapter is using sanded down chip or sunplus then they may cause DMA issue.
I ruled out adapters 100% by connecting the SSDs directly to newer chipsets with native sata support and they also don't work in mwdma modes with ssds. Also tried PCI controllers with native sata support, they also don't work in any mwdma modes, again only when using SSDs.
It's not the operating systems, chipsets or adapters, the only common part in all this is the SSDs.
During tests i have done, Mwdma modes work in all the old and new chipsets and OS's but only with spinning HDs, CF cards and SD cards.
The reason I am doing this is it's getting cheaper to use SSDs than CF and SD cards. I have a lot of motherboards with 430FX, 430HX and 440fx chipsets, the 1995 to early 1997 period. These boards support only one dma mode, mwdma. Without mwdma they are stuck in PIO mode and then the SSD is much slower than CF and SD cards that can work in mwdma modes. It's kills performance in Win9x and Win2k on these systems, especially PPro boards using Win2k.
SSDs just don't work in any MWDMA modes, regardless of motherboard chipset (have tested on boards from 1995 430fx to Z390 chipsets), Win, Linux, Dos.