VERSION: AGPtimer 1.1 3/15/02 DESCRIPTION: This utility will allow the modification or display of the PCI latency timer of an AGP card if it's located at device 0, bus 1, function 0. This information can be verified by using Sisoft Sandra and looking at the PCI, AGP, Cardbus buses option then clicking on the AGP bus. If your AGP video card is not device 0, bus 1, function 0 on the AGP bus I'd like to hear about it. Probably the best use for this utility is in reducing the PCI latency timer for your AGP card. According to the PCI Latency How To, PCI latency timers should be less than 64 clks. My Nvidia GEforce 2/GTS was running 248 clks, which I reduced to ~100 clks w/no loss in framerate. This also eliminated the problems I had when loading Undying on my KT133 system. I would always get a BSOD w/the message "disk error writing to drive x: data or files may be lost". By reducing the PCI latency timer to around 100 clks this problem disappeared. USAGE NOTES: This version fixes a bug which overwrote the line cache size. Personally, I don't use AGPtimer at all anymore I use PCItimer which is more flexible. I've only tested my utility on a VIA MVP3 based system, a VIA KT133 and a Soyo Vempro based system under Windows 98. I'm planning on personally testing it on at least four more different types of motherboards. This utlity should work on all AGP vid-cards located at bus 1, device 0, function 0. The utility should be run from a DOS box while in windows 95/98. I would first make certain my AGP vid-card is at bus 1, device 0, function 0 by looking at Sissoft Sandra's PCI, AGP, Cardbuses information and checking the AGP bus. NT doesn't seem to like real-mode code so I doubt it would run under NT, Windows 2000 or Windows XP. It would be a good idea to first note the original value before changing it. You can do this by running agptimer -c or agptimer -C. The worst problem I've experienced using this utility is video corruption. Shutting down and restarting windows restores your AGP PCI latency timer to it's default value, so that would be a way to overcome this problem if it occurs. Personally I've found I get greater stability on my KT133 system by reducing the AGP PCI latency timer's value to 128 or less (this is for a GeForce 2/GTS AGP) from 248 clks. If you do a search on PCI latency How-To you'll find that PCI latency timer values of over 64 clks aren't recommended. As a matter of fact I've experienced no reduction in performance when I reduced my GeForce 2/GTS AGP PCI latency timer value to ~100 clks. It's possible not all AGP video cards implement their PCI latency register at the same offset D. This sucks because it seems like none of the video-card manufacturer's today publicly publish their data sheets so there's no way of knowing where they implement their PCI latency register. Also if your AGP card doesn't do bus-mastering (I know for a fact the PCI 3dfx Voodoo 3/2000 didn't do bus-mastering) there will be no latency timer to modify! It also seems like a lot of people w/on-board AGP vid-cards are having problems. Until I get more information on this there's not much I can say about it or fix. Personally, I've added agptimer to the startup taskbar and start menu as a DOS app and then check close-on-exit. This is the way I'm using it on my KT133-based Gigabyte 7zx. Settings -> Taskbar and Start Menu -> Start Menu Programs. On all three motherboards I've tested the AGP PCI latency timer value is reset to it's default value on reboot. BUG REPORTING: If you've got any problems it's best to send me the specs on your AGP vid-card by using Sisoft Sandra. What I'd like to know is what device #, bus # and function # your AGP vid-card is using, it's current latency timer value and whether or not it's bus-master capable (both found in Sisoft Sandra's PCI, AGP, Cardbus buses information, AGP). Also, I'd like to know what interfaces your PCI bus supports (found in Sisoft Sandra PCI, AGP, Cardbuses information generic). RESPECTS/THANKS TO: Jari Korhonen parru@mbnet.fi http://koti.mbnet.fi/parru/ author of the original PCI latency utility: latency.exe.