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PCI Delay Transaction

Posted: Fri Oct 11, 2002 3:49 am
by gpc
I have a Gigabyte GA-7vtxh motherboard with an ami bios (f7). Can someone tell me what PCI Delay Transaction setting is for? Default is (enabled). Can I speed anything up by disabling this? Thanks for your help.

GPC :)

Posted: Fri Oct 11, 2002 5:02 am
by soupy

Posted: Fri Oct 11, 2002 11:48 am
by Rainbow
Enabled should be faster. And it must be enabled for the PCI bus to be fully PCI 2.1 compatible.

Posted: Fri Oct 11, 2002 1:30 pm
by NickS
It's probably to allow an ISA bus mastering LAN card to work. The bus hold time for DMA transfer on an ISA bus LAN card with a full buffer exceeds the maximum for the PCI spec. Solutions; rewrite the LAN card driver or allow the ISA bus to hold longer. If you do nothing LAN performance drops due to timeouts and retries. At work we had to swap hundreds of LAN cards to non-Bus-mastering (Programmed I/O) cards. We had a BIOS patch but the engineers didn't seem to be able to apply it consistently.

Posted: Sat Oct 12, 2002 5:19 am
by gpc
I don't have any isa slots on the board, but I do have an onboard Realtek 8100 series lan chip. But I currently have the onboard lan disabled, I'm not using it and it speeds up boot time slighty, and I believe it uses the pci bus. So it doesn't look like I need pci delay transaction accept for pci 2.1 compatability. Would this cause any problems. What got me started on this is the way my printer takes over the computer when printing, pages won't scroll right and slows down everything until it's done. It's configured: IRQ 7 LPT1 (by itself), ECP, Spooling, and have latest drivers. Have tried EPP. I don't understand why a printer could slow down a 1600Mhz processor with 512MB of DDR ram. Is this normal? I'm looking for possible configuration problems.

If I'm in the wrong section of the forums let me know, I'm obviously not a programming guru.


gpc :) I wanted to add it's a Via KT266A chipset and I'm still using Windoze 98SE

Posted: Sat Oct 12, 2002 9:15 am
by Denniss
Depending on the printer - some have it' own processor to reformat received data into printable format and others use Computer resources for this calculation .

Posted: Sat Oct 12, 2002 9:29 am
by NickS
I second DennisS's statement. "Dumb" printers rely on the processor to do all the conversion into bitmap format, while a printer which handles PostScript or HPGL directly will take that load off the CPU. That also means that dumb printers tie up the CPU watching the LPT port while they transfer a bit map instead of a few lines of page description language. (IRQs may be defined but unfortunately that does not necessarily mean they are used, especially in SPP mode).

ISTR that the VXD for the parallel port in W98 has a bug and only does SPP, but that shouldn't make any difference when printing, just when using Direct Cable Connection through the parallel port.

Posted: Sat Oct 12, 2002 6:33 pm
by KachiWachi
Since it was brought up, could someone elaborate on the differences between ECP and EPP, and which you should set and why? Which came first?

Posted: Sat Oct 12, 2002 7:54 pm
by Denniss
SPP was first
Later ones are improvements to get higher data transfer rate with less CPU consumption - fastest should be ECP as it get a DMA channel - usually DMA3

Posted: Sun Oct 13, 2002 12:25 am
by gpc
Great! That's a non-issue I can check off my list. It's my low end printer. Thanks for all your help.


Posted: Sun Oct 13, 2002 3:32 pm
by KachiWachi
Thanks Denniss ---

Now what about a BIOS that has a setting EPP/ECP?? Is this a *smart* port that can switch modes depending on the connected device?

I know on my girlfriends old computer (i430HX), setting EPP/ECP worked great when I had my ZIP-100 connected there, but her old Epson printer would print gibberish at that setting...had to set the port to SPP for it to work properly.

Why would that be?? Just plain transfering the data too fast??

Posted: Sun Oct 13, 2002 8:21 pm
by Rainbow
Some boards have problems like this, some don't. On my Asus P2B, I have LS-120 drive connected to parallel port and Star LC24-200 Colour printer connected through the LS-120. The port is set to ECP/EPP in BIOS and everything works without any problems.
On my other computer with MSI MS-5120, I have old HP LaserJet IIIP printer. Port is set to ECP/EPP and no problems too.

Posted: Sun Oct 13, 2002 8:32 pm
by Denniss
On my ECS P5VX-Be I have a HP540 but is has sometimes problems with ECP/EPP but ECP works fine .
My ZIP100 Plus works fine in both modes - a little faster in ECP ( but fastest connected to SCSI :D ) .