PCI streaming/latency, Verite 3D accelerators and HX/VX

I was wondering if someone can confirm this for me. Is it true that PCI streaming / latency is disabled in all the new (and supposedly better) HX/VX chipsets, whilst the old FX has these options. Did Intel leave these options out of the chipset register? I have a 3D Blaster PCI and can only get 39.0 for DMAtest. Many other people are getting 78+. And it makes a HUGE difference to framerates in Nascar2 etc. And on a related topic, how come DMA bus mastering is enabled for the video card in Win 95 but not in dos. What is the BIOS doing to disable it? I can get around this using vtool but I am still curious. Is there any way around the PCI streaming / latency issue or is it going to remain a fact that old FX motherboards are going to be superior for gamers who use a Rendition Verite based 3D accelerator? My system: p166 Tyan Tomcat 1 Rev3 Tomcat Bios 2.22 Award 4.51PG Intel HX chipset 32 Megs EDO 3D Blaster PCI SB 32 WD 2.5 GB HD Thanks in advance Anton Voss

I have quite new QDI 51430HX-T2 and there is option for PCI latency. It carries AMIBIOS but I know that another board (same model) wich carries AWARD bios do not have those options. So I think it's upon to motherboard- and bios manufacturer not HX/VX chipset.

: >I was wondering if someone can confirm this for me. Is it true that PCI : >streaming / latency is disabled in all the new (and supposedly better) : >HX/VX chipsets, whilst the old FX has these options. Did Intel leave these : >options out of the chipset register? : > : I have quite new QDI 51430HX-T2 and there is option for PCI latency. : It carries AMIBIOS but I know that another board (same model) wich : carries AWARD bios do not have those options. So I think it's upon to : motherboard- and bios manufacturer not HX/VX chipset. Having looked at the Docs for the 430HX chipset, PCI latency seems to be handled completely different than in the FX series. I cannot find a similar register in the HX set for setting the PCI latency timer that matches the FX set. However, I think it is something that Award seems to have left out of their BIOS. I see no mention of a PCI Latency timer in any of the BIOS docs at Award's web site. I too have heard of other HX boards having this option in their BIOS. I don't think it is necessarily "disabled", but usually set to a low rate. I have sent e-mail to Tyan about this issue and have yet to receive an answer. And yes I did send it to "tech support" not the web master... (It seems that Jerry Lee is the only person at Tyan to answer my e-mail.) -- **************************** Michael E. Carver ************************* Upside out, or inside down...False alarm the only game in town. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./. [- < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

I don't believe that PCI streaming is disabled on "all" HX/VX boards. On my ASUS P55T2P4 (HX board) there is an option to enable/disable PCI streaming in the BIOS setup. I am pretty sure it has an Award BIOS, but I don't have the machine in front of me, and I haven't played with the BIOS for awhile. A number of people have stated that the Tomcat boards may not be the best choice to pair with a Rendition video board due to the Tomcat's lower DMA numbers. I still feel that the HX chipset is the preferred Pentium chipset for ***, due to its ability to run the higher bus speeds (75/83 MHz). With my ASUS bus running at 75 MHZ the system is rock solid in both DOS and Win95, and it seems to be a good match with the Reactor. I am very pleased with this combination, and it was a *lot* cheaper than buying a PPRO 200! Of course, this could all change as soon as boards capable of pairing SDRAM and higher bus speeds become available. ;-) --Marcus

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>I was wondering if someone can confirm this for me. Is it true that PCI >streaming / latency is disabled in all the new (and supposedly better) >HX/VX chipsets, whilst the old FX has these options. Did Intel leave these >options out of the chipset register? >I have a 3D Blaster PCI and can only get 39.0 for DMAtest. Many other >people are getting 78+. And it makes a HUGE difference to framerates in >Nascar2 etc. >And on a related topic, how come DMA bus mastering is enabled for the video >card in Win 95 but not in dos. What is the BIOS doing to disable it? I can >get around this using vtool but I am still curious. >Is there any way around the PCI streaming / latency issue or is it going to >remain a fact that old FX motherboards are going to be superior for gamers >who use a Rendition Verite based 3D accelerator? >My system: >p166 >Tyan Tomcat 1 Rev3 Tomcat Bios 2.22 Award 4.51PG Intel HX chipset >32 Megs EDO >3D Blaster PCI >SB 32 >WD 2.5 GB HD >Thanks in advance >Anton Voss

Just in case you wanted to know, I just did a quick comparison of my ABIT VX board with 32megs SDRAM to Mike Schreiner's ASUS HX with 64megs EDO both with P200MMX CPUs. Here's a quick run down on what we both got at 200mhz (66x3) using WinBench97 and Chris Dial's 3D Bench: Mine His CPUMark16 442 409 CPUmark32 427 389 SVGA(fps) 41.0 40.7 I usually run my system at 225mhz (75x3) which gives me these scores: P225MMX CPUMark16 470 CPUmark32 458 SVGA(fps) 46.2 -- The IWCCCARS Project: Q & A Representative [link lost in import] [link lost in import: /~ebusch/]

If I'm not mistaken, the Asus P54t2p4 motherboard uses the HX chipset. The award bios I have has a PCI latency adjustment. Jeff

> I don't believe that PCI streaming is disabled on "all" HX/VX boards. > On my ASUS P55T2P4 (HX board) there is an option to enable/disable > PCI streaming in the BIOS setup. I am pretty sure it has an Award > BIOS, but I don't have the machine in front of me, and I haven't played > with the BIOS for awhile. I just assembled my new system with an Asus P55T2P4 (ver 3.1), 512K cache, 32 EDO, P166 MMX, and a Reactor 3D. The Asus has Award bios and there is a line for PCI latency timer. My board came with this item set at zero, so I tweaked it to 32 (so far). I have asked Eric Busch for some additional help, waiting to hear from him . My scores for DMAtest are as follows: Nominal FIFO = 20.2 MB/sec Good Luck Bob

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>> I don't believe that PCI streaming is disabled on "all" HX/VX boards. >> On my ASUS P55T2P4 (HX board) there is an option to enable/disable >> PCI streaming in the BIOS setup. I am pretty sure it has an Award >> BIOS, but I don't have the machine in front of me, and I haven't played >> with the BIOS for awhile. >I just assembled my new system with an Asus P55T2P4 (ver 3.1), 512K >cache, 32 EDO, P166 MMX, and a Reactor 3D. The Asus has Award bios and >there is a line for PCI latency timer. My board came with this item set >at zero, so I tweaked it to 32 (so far). I have asked Eric Busch for >some additional help, waiting to hear from him . My scores for DMAtest >are as follows: > Nominal FIFO = 20.2 MB/sec >Good Luck >Bob

I have the same setup as you and my scores are: Nominal fifo = 22.2 mb/sec I have the bus speed at 68 mhz and the latency timer at 150. Barry Clay

: Having looked at the Docs for the 430HX chipset, PCI latency seems to be : handled completely different than in the FX series. I cannot find a : similar register in the HX set for setting the PCI latency timer that : matches the FX set. However, I think it is something that Award seems : to have left out of their BIOS. I see no mention of a PCI Latency timer : in any of the BIOS docs at Award's web site. I too have heard of other : HX boards having this option in their BIOS. I don't think it is : necessarily "disabled", but usually set to a low rate. I have sent : e-mail to Tyan about this issue and have yet to receive an answer. And : yes I did send it to "tech support" not the web master... (It seems : that Jerry Lee is the only person at Tyan to answer my e-mail.) Tyan, I am still waiting. Have not received a reply to my questions sent to Tech Support via web site. Why do we not have control of the PCI Latency timer in our Award BIOS'es? Can we expect to get such in the next upgrade? This question has been asked before and I have never seen a response (public or private). -- **************************** Michael E. Carver ************************* Upside out, or inside down...False alarm the only game in town. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./. [- < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

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>>I have the same setup as you and my scores are: >>Nominal fifo = 22.2 mb/sec >>I have the bus speed at 68 mhz and the latency timer at 150. >>Barry Clay >May I ask you all why, do you adjust the PCI Latency Timer so high??? >My timer is at 75 and my dma figures are at 118.x mb/s with an 83bus. >I feel like I am too high at this setting because of the bus. I know >that the default setting on my board is 32. I am going to adjust it >'til I get down to the 90mb/s bracket. Setting it to high I believe >will cause trouble for some of your ISA cards.. >take care..

I only chose that setting of 150 till i get to work it down till I see a change. At this point I don't have any problems with isa cards or my system. Barry Clay

I have the Asus PT55T2P4 with 32 megs edo ram, Intel P133 with the Intergraph Intense 3D 100 video card. The book says to set the pci latency timer at 32. With that setting I got a reading of nominal dma performance= 67.3 mb/sec. I bumped the pci timer up to 54 and got a reading of 89.8 mb/sec

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> >I have the same setup as you and my scores are: > >Nominal fifo = 22.2 mb/sec > >I have the bus speed at 68 mhz and the latency timer at 150. > >Barry Clay > May I ask you all why, do you adjust the PCI Latency Timer so high??? > My timer is at 75 and my dma figures are at 118.x mb/s with an 83bus. > I feel like I am too high at this setting because of the bus. I know > that the default setting on my board is 32. I am going to adjust it > 'til I get down to the 90mb/s bracket. Setting it to high I believe > will cause trouble for some of your ISA cards.. > take care.. > Julian Data > IVGA Member #0004 > Director of Information Technology > ACE Beta Tester and Driver of IVGA > Channel Operator of #ivga on IRC (Undernet) > Powered by IVGA Pro Gamer System P6-200 oc 233, 96MB EDO

PCI Latency is on the individual card, in that cards PCI configuration space, that is part of every PCI plug in card. It is NOT part of the chip set. Some BIOSs let you set this number, some default to 'some' number. This register is only used for bus masters. Usually only disk controllers and network adapters provide the bus master function. Video cards may or may not. The PCI revision 2.1 spec says 16 should be the maximum number. What PCI latency is, is for how many data cycles a bus master can keep the bus once it has been granted permission to use the bus. If you set it to high, other cards may not get the bus in time, and may loose data. Honestly, I wouldn't believe there would be a problem setting it to 32, but I wouldn't set it to much higher than that. Austin Franklin

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> PCI Latency is on the individual card, in that cards PCI configuration > space, that is part of every PCI plug in card. It is NOT part of the chip > set. > Some BIOSs let you set this number, some default to 'some' number. This > register is only used for bus masters. Usually only disk controllers and > network adapters provide the bus master function. Video cards may or may > not. > The PCI revision 2.1 spec says 16 should be the maximum number. What PCI > latency is, is for how many data cycles a bus master can keep the bus once > it has been granted permission to use the bus. If you set it to high, > other cards may not get the bus in time, and may loose data. Honestly, I > wouldn't believe there would be a problem setting it to 32, but I wouldn't > set it to much higher than that. > Austin Franklin

When I first looked at my PCI latency setting (before any adjustment) it was set to "66." This is much higher than your suggested 32 and that was the factory setting. I adjusted it to "90" and my DMAtest scores went up to "93.5 MB/sec" and no resulting problems have occured. -- Matt Lewis

It really depends what you use your system for. If you are using DOS or Win 3.1 or even Win 95, and you have no real time requirements, you will probably not get any effect from what ever number you put in it. If you are running a server, or running NT, you may get some slow downs in certain places. There is no DMA per se in PCI land. I don't know what the test you are refering to does. Also, be aware that these tests are not any reflection of any real world situations. They are dedicated for that one and only function, and do not show any interactions with other parts of the system that may be affected by other changes. If your BIOS set that to 66, then it determined that the requirements of your system were pretty small, and the large number would not cause any problems. You're proably safe with what you did. If you had a network card, graphics card, two disk controllers, etc. then it probably would have set the number much lower. It's only an 8 bit regiseter, which means it can be as large as 255 decimal. By the way, I believe in the earlier post I said the latency timer was in units of data phases, it's not, it's in units of PCI bus clocks. Austin Franklin

If your name is Perry, you can talk while the computer is working, thus the term "Perry Concurrency".

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> > PCI Latency is on the individual card, in that cards PCI configuration > > space, that is part of every PCI plug in card. It is NOT part of the chip > > set. > > Some BIOSs let you set this number, some default to 'some' number. This > > register is only used for bus masters. Usually only disk controllers and > > network adapters provide the bus master function. Video cards may or may > > not. > > The PCI revision 2.1 spec says 16 should be the maximum number. What PCI > > latency is, is for how many data cycles a bus master can keep the bus once > > it has been granted permission to use the bus. If you set it to high, > > other cards may not get the bus in time, and may loose data. Honestly, I > > wouldn't believe there would be a problem setting it to 32, but I wouldn't > > set it to much higher than that. > > Austin Franklin > When I first looked at my PCI latency setting (before any adjustment) it > was set to "66." This is much higher than your suggested 32 and that > was the factory setting. I adjusted it to "90" and my DMAtest scores > went up to "93.5 MB/sec" and no resulting problems have occured. > -- > Matt Lewis

Mine too is set to 66, factory setting. But my bios book says i shouldnt change it, will it***ought if i do increase it, will nt 4.0 die? --Sam

Mat, The problem with these test scores is they only exercise the one thing you are testing. They don't let you see what the effect on the other aspects of your system may be. If you are testing out the speed of your video, to see the effects on your hard disk controller, you need to run them both in some kind of real world test, or the numbers are purely academic. How often to you just use your video card....all by it self...with no other cards using the PCI bus (or the system for that matter)? I don't think you'll see any problems going from 66 to 90. The only time this may effect your other cards (i.e. disk controller) is if you are doing full motion video, and the video is being used constantly. Then the disk would be slower, because it can't get as much bus bandwidth as it needs. The disk slow down could be negligable to somewhat significant, it depends on many different things. The tests that just test one thing, i.e. main memory speed, or DMA test just give singular results. Real world tests, like the ZD labs tests (ala PC Magazine testing) give a much more accurate representation as to how the overall system is performing. They're free too! Austin Franklin

I have a Tomcat III w/Award 4.51PG version 4.0E Can I change my latency settings, and if so, how? Sincerely, Jonathan E. Schneeweis On 7 Feb 1997 13:53:04 GMT, "Austin Franklin"

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>> When I first looked at my PCI latency setting (before any adjustment) it >> was set to "66." This is much higher than your suggested 32 and that >> was the factory setting. I adjusted it to "90" and my DMAtest scores >> went up to "93.5 MB/sec" and no resulting problems have occured. >Mat, >The problem with these test scores is they only exercise the one thing you >are testing. They don't let you see what the effect on the other aspects >of your system may be. If you are testing out the speed of your video, to >see the effects on your hard disk controller, you need to run them both in >some kind of real world test, or the numbers are purely academic. How >often to you just use your video card....all by it self...with no other >cards using the PCI bus (or the system for that matter)? >I don't think you'll see any problems going from 66 to 90. The only time >this may effect your other cards (i.e. disk controller) is if you are doing >full motion video, and the video is being used constantly. Then the disk >would be slower, because it can't get as much bus bandwidth as it needs. >The disk slow down could be negligable to somewhat significant, it depends >on many different things. >The tests that just test one thing, i.e. main memory speed, or DMA test >just give singular results. Real world tests, like the ZD labs tests (ala >PC Magazine testing) give a much more accurate representation as to how the >overall system is performing. They're free too! >Austin Franklin

: I have a Tomcat III w/Award 4.51PG version 4.0E : Can I change my latency settings, and if so, how? : Sincerely, : Jonathan E. Schneeweis You can't with the Award BIOS'es provided by Tyan. I am not even sure if their AMI BIOS have a PCI latency setting. I have asked Tyan tech support about this time and time again. I have yet to receive a reply from them about this issue. I suggest you sent them some e-mail letting them know you would like to have control of the PCI latency timing in the next BIOS upgrade. It's possible to do, other Award BIOS'es seem to have this for the HX/VX chipset. -- **************************** Michael E. Carver ************************* Upside out, or inside down...False alarm the only game in town. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=<[ /./. [- < ]>=-=-=-=-=-=-=-=-=-=-=-=-=-=

The Tyan Titan III AMI BIOS does have a PCI latency setting. ---------------------------------------------------------------------- This space intentionally left blank

I have a Tyan S1470VX Triton III motherboard that does NOT have the PCI Latency Setting. >>You can't with the Award BIOS'es provided by Tyan. I am not even sure >>if their AMI BIOS have a PCI latency setting. I have asked Tyan tech >The Tyan Titan III AMI BIOS does have a PCI latency setting. >---------------------------------------------------------------------- >This space intentionally left blank

>When I first looked at my PCI latency setting (before any adjustment) it >was set to "66." This is much higher than your suggested 32 and that >was the factory setting. I adjusted it to "90" and my DMAtest scores >went up to "93.5 MB/sec" and no resulting problems have occured. This is all interesting. Out of sheer curiosity after this discussion lasted a while I went on to look at my default setting on my Asus PPro board, an XP6NP5 - 32. All the manual states is that this is the optimal setting for the motherboard. That's it! Stuart -- Stuart Booth Somewhere in Oxfordshire, England, UK Note: My email address is in disguise! Remove trailing Z