DMA buffer question

[daveleau]

Hi everybody,
I read a post here by BBA while reading up on optimizing the swap file about ways to optimize Windows and saw something I haven't looked into before...the DMA buffer settings. What should I set it to? Is 64K good for all systems? Or should I set it to half the proportion of my RAM (384MB PC100)? Thanks for any help...
Dave

Also should I set my swap file to double my RAM as well? That's alot of virtual memory! Almost a gig! And thanks to Socal for explaining vcache to me. http://sysopt.earthweb.com/forum/smile.gif

[This message has been edited by daveleau (edited 06-20-2000).]

[chipbgt]

From what I remember, your swap file should be twice you ram..but it only goes for up to a point....It depends on what you use. I would think 150 mb of VM would be plenty.

[This message has been edited by chipbgt (edited 06-20-2000).]

[daveleau]

Thanks Chip.

Any idea about setting the DMA buffer? I had mine set to 64Kb but it seemed to slow my system down.

I set up a "conservative swap file" in my system.ini and it seemed to speed the system up a good deal...on bootup especially. To do it, go into your system.ini and search for the [386enh] heading. Insert "ConservativeSwapFile=1" w/o quotes. I will give a link if anyone is interested in exactly what it does. It has been posted here as well.
Thanks
Dave

[BFlurie]

I don't think you can set the DMA any higher than 64K. In addition to the:

[386Enh]
DMABufferSize=64

entry in system.ini, you can also change it in Device Molester/ System Devices/ Direct memory access controller/ Memory. I'm not sure why 64K would slow your system down. The default is like 16K(?), so try 32K or just uncheck it to get the default & compare.

[daveleau]

Thanks! I will try that.
Dave

[BFlurie]

One more thing, though it's not DMA related. I came across this recently. If you have alot of memory, you can specify a larger than normal memory buffer for specified IRQs used by hard-drives, Video cards, etc. For instance, here's my System.ini [386Enh] entries for a 4 MB buffer for each of the following IRQs:

[386Enh]
Irq11=4096
Irq14=4096
Irq15=4096


[This message has been edited by BFlurie (edited 06-22-2000).]