VOGONS


Voodoo 2 SLI and 1024x768

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Reply 20 of 60, by Jade Falcon

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Haveing made drivers and working with the voodoo2 sli setups as much as I have I can honestly say that FFXIhealer option is not only wrong but its down right foolish to even believe it. How is it if both cards are rendered the same image that sli increases FPS?
A quick internet search on AFR and 3dfx sli will give you troves of info stating that your wrong.

https://en.m.wikipedia.org/wiki/Alternate_frame_rendering

Scan-Line Interleave: The origin of the SLI trademark, as employed by the 3dfx Voodoo2, which renders a frame's even scan-lines on the first GPU and its odd scan-lines on the second.

Reply 21 of 60, by FFXIhealer

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Rendering and Drawing are two different things.

Because in the rendering the scene in triangles and textures, that's easy. Mapping out what pixels need to be drawn on the screen BASED on those triangles and textures, how far they are from the perspective of the camera, the angle the surface needs to be at, etc. that's the tough part. It's the DRAWING that has been cut in half effectively, not the rendering. They BOTH have the same image to render, but don't have to do nearly as much work trying to draw the thing since each card can effectively skip drawing half of the required pixels on the screen (1024x384 effective, or 393,216 pixels per frame instead of the full 786,432 pixels - by contrast, 800x600 only requires 480,000 pixels per frame, so each card only has to render 240,000 pixels per frame, hence increased framerates). So in this way, the two cards are DRAWING differing things per frame, but they have RENDERED the same frame in memory. The 2nd card just passes its pixel stream data to the first card timed by clock-cycle so the first card can send the completed data to the monitor out via the VGA port. Also keep in mind that back here, the CPU is doing most of the transform, lighting, and extra calculations and the video card is only really having to render the image using the data it's given. It isn't nearly as complicated as it is after the GeForce and Radeon cards were released that ...well, pretty much do damned near everything now.

Scan-Line Interleaving
Multi_gpu_scan_line_interleave.png

Sorry about the language (I have no idea what it is - German?). It's the only image of what I wanted to show that I could find on such short notice without having to draw my own).

NVidia's SLI (scalable Link Interface) isn't even the same thing. I couldn't even begin to tell you what those cards are doing.

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Reply 22 of 60, by firage

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Unnecessarily splitting hairs over terminology - rendering and 'drawing' are synonymous, and what parts of the process one understands as an image appears to be a subjective take. Both cards have the textures and geometry for the full frame, but each only renders half of the frame into their frame buffers. Thus the SLI setup has the same texture memory capacity as a single card, but doubled frame buffer memory.

My big-red-switch 486

Reply 23 of 60, by Jade Falcon

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Wow someone is really miss informed and getting way to technical on terminology. Rendering, drawing and displaying are the same thing.

In layman terms, both cards have the same data in vram. They have the same intrusions to render the whole image, but etch card only renders half of the intrusions in ram.

This is what AFR is. Vram is mirrored across all the cards and etch card renders/draws/displays every other line of pixels or half of the screen. Its the same with Nvidia sli in AFR mode.

Reply 24 of 60, by The Serpent Rider

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Voodoo 2 SLI have shared frame buffer, both cards render half of it simultaneously. It has nothing to do with AFR method, which renders full frames.

A quick internet search on AFR and 3dfx

Quotes from that article.
"AFR belongs to a class of parallel rendering methods"
"If a computer has two video cards that combine their outputs into a single video monitor, then one of four methods could be used to create the images."

I must be some kind of standard: the anonymous gangbanger of the 21st century.

Reply 25 of 60, by appiah4

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SLI is not AFR, the cards render seperate halves of the image and certainly do not render the same image. I don't know how many times this needs to be said before FFXIHealer gets it, but it is what it is.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 26 of 60, by FFXIhealer

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Because none of you are actually LISTENING to me. You're too busy trying to convince me how I must be wrong because you guys think differently.

I have a degree in Computer Science because I've taken programming classes, programming algorithms, AND MOST IMPORTANTLY, ASSEMBLY LANGUAGE. I've also studied Electrical Engineering in college, including circuit design. I also know the steps the Voodoo2 has to take in the data path in order to generate the 3D image and you guys are simply ignoring me instead of even remotely trying to pay attention.

The card has to RENDER THE IMAGE IN MEMORY so that the drawing rasterizer has something in memory to generate the pixels from. The screen you are looking at is drawn one pixel at a time, in lengthwise order, usually from right to left on the screen, The lines of data include a start and stop code, plus the wait time the monitor needs in the data stream before it begins drawing the next line up with the next start code. The graphics card receives the data to render the image via the PCI bus from the CPU, having already been corrected for view position, lighting, vertex positions, and everything else the CPU has to do to the data before the Voodoo card can render the image. The CARD has to take the vertex points and plot the surfaces out in a virtual 3d environment so that it has something to work with in terms of applying textures to the surfaces and distances from the camera - all so that the framebuffer can be loaded with a stream of pixels, again calculated via distance from viewpoint, position relative to viewpoint, and angle from viewpoint. What the hell do you guys think those three big-ass chips on the Voodoo2 card is doing? Juggling numbers? And don't forget the Gendac ship. It's a clock generator and a DAC in order to convert all those digital pixels into an analog signal for the monitor to use.

But I WILL stipulate to one thing. If the remaining 4MB is specifically for the Framebuffer and not being used entirely for media rendering, then it is possible that the stream of pixels (which will be different per V2 card) is waiting inside that framebuffer for the GENDAC chip to send to the monitor - in which case the framebuffer would NOT hold identical information per card. But the video card has to have a place to save where all the pixels are in the frame and that wouldn't necessarily need all 4MB. The Voodoo1 cards had 2MB of framebuffer and could do the job, including the pixels. But BOTH Voodoo2 cards still have to have the exact same frame to render. They're just not drawing the same pixel stream. And I'm sitting here getting tired of trying to argue with people who are more interested in arguing with me and don't actually BACK UP THEIR ARGUMENTS. We've got people in this thread who don't even know how the Voodoo2 SLI setup works trying to talk! I'm done. I'm not coming back to this thread again.

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Reply 27 of 60, by derSammler

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FFXIhealer wrote:

I have a degree in Computer Science because I've taken programming classes, programming algorithms, AND MOST IMPORTANTLY, ASSEMBLY LANGUAGE. I've also studied Electrical Engineering in college, including circuit design.

Whenever people are wrong, they come with stuff like this. Even if you were on the moon, it wouldn't make your statement right. Oh, and why do you put emphasis on assembly? How does that correlate to the discussion? You are simply not able to understand the difference between IMAGE and FRAME.

Reply 29 of 60, by the Goat

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FFXIhealer wrote:

Dude, you need a dictionary. It's RENDERING THE IMAGE. IN MEMORY. The exact same triangles, the exact same textures, the exact same image.

. . .

I have a degree in Computer Science . . .

Well, I have a degree in Electrical Engineering and a degree in Computer Science, and I can say with 100% certainty that VooDoo 2 cards in an SLI configuration do not render/draw/generate/etc the same image on both cards.

If they both rendered the same image, wouldn't it be easier to use one card to render the image at half height, then draw each line twice?

Reply 30 of 60, by leileilol

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The obsessive fixation on ASSEMBLY is from the younguns that find awe in games that are "coded in assembly therefore it's the best" for its notability, despite being more of a commonplace thing.

"Knowing ASSEMBLY" doesn't automatically give you the Abrash cred and let you win the internet.

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Reply 31 of 60, by hasnopants

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Argument aside...🤣.

Do you guys think maybe my Voodoo 2s could be overheating? Do you think that my FSB might be too high? Remember I am using a 1ghz coppermine CPU. Would it be worth downclocking the CPU and getting a fan for the voodoos and trying again?

Current Systems:
DIP40|8088|640K|HERCULESGB102|PCSPKR
DIP40|V20|640K|VGA|ADLIB/TNDY/COVOX
S7|P233MMX|128M|S3ViRGEDX/DM3D|SB16
S370|P600MMX|256M|SIS630/DM3DIIX2|SBLIVE!5.1
S775|P43.4|2G|6800GS|SBAUDIGY

Reply 32 of 60, by clueless1

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hasnopants wrote:

Argument aside...🤣.

Do you guys think maybe my Voodoo 2s could be overheating? Do you think that my FSB might be too high? Remember I am using a 1ghz coppermine CPU. Would it be worth downclocking the CPU and getting a fan for the voodoos and trying again?

Why don't you try and report your results here 😀

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Let's benchmark our systems with cache disabled
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Reply 33 of 60, by firage

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I think F2bnp pretty much said it,

F2bnp wrote:

I don't know what to tell you, I'm thinking your best bet is to test each card individually at 800x600 with something like 3DMark 2000 that will push them to the max. That way you'll see whether or not one of the two cards is having issues.

It does sound like something's not working right.

My big-red-switch 486

Reply 34 of 60, by hasnopants

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Both cards locked up in 3dmark 2k pretty much instantly, not sure now what driver I was using but I'm not sure i have the patience/time to really mess with these much anymore. It would just be a bummer if it was something simple I was missing, hence why I came here. I will probably set them aside for now and maybe pick it up again fresh later.

Current Systems:
DIP40|8088|640K|HERCULESGB102|PCSPKR
DIP40|V20|640K|VGA|ADLIB/TNDY/COVOX
S7|P233MMX|128M|S3ViRGEDX/DM3D|SB16
S370|P600MMX|256M|SIS630/DM3DIIX2|SBLIVE!5.1
S775|P43.4|2G|6800GS|SBAUDIGY

Reply 35 of 60, by firage

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Okay, if they both did that individually, you're on the right track with cooling. Get some active cooling on/around them temporarily to test.

I think the checklist then continues with CPU cooling, memory, and finally component failure on the motherboard, which should all show up as instability in intensive non-graphical testing e.g. Prime95, Memtest86.

My big-red-switch 486

Reply 36 of 60, by hasnopants

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Ok thank you Firage. I will try active cooling on the Voodoos.

Current Systems:
DIP40|8088|640K|HERCULESGB102|PCSPKR
DIP40|V20|640K|VGA|ADLIB/TNDY/COVOX
S7|P233MMX|128M|S3ViRGEDX/DM3D|SB16
S370|P600MMX|256M|SIS630/DM3DIIX2|SBLIVE!5.1
S775|P43.4|2G|6800GS|SBAUDIGY

Reply 37 of 60, by appiah4

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Fsb overclock may also be causing it try running it at 66mhz fsb.

Retronautics: A digital gallery of my retro computers, hardware and projects.

Reply 38 of 60, by hasnopants

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From my previous post:

I thought I read somewhere where the FSB being too fast might screw up voodoo 2 sli. So I tried this...I lowered my clocks to 66/66...so my 1000EB down-clocked to 500 mhz and my FSB down-clocked to 66 mhz. Lo and behold different results. Unreal flyby actually plays for a bit sometimes, one time it kept the first frame on the screen sort of translucent while it flyby'd in the background at the right resolution.

So then I got another idea, I have another machine I've been working on a win95/DOS machine (ostensibly DOS really). So I pulled the cards out of my 1ghz machine and put them in this much slower machine running a Pentium 1 w/ MMX at 233mhz, 128 mb of PC100 SDRAM, VIRGE DX, Sound blaster 16

Loaded the 3.02 win 9x driver on windows 95 and installed unreal on the machine. Checked system info and got it to SLI detected 8mb/8mb. Started up unreal flyby and it ran fine on all resolutions except when I switch to 1024x768 it locks up.

Current Systems:
DIP40|8088|640K|HERCULESGB102|PCSPKR
DIP40|V20|640K|VGA|ADLIB/TNDY/COVOX
S7|P233MMX|128M|S3ViRGEDX/DM3D|SB16
S370|P600MMX|256M|SIS630/DM3DIIX2|SBLIVE!5.1
S775|P43.4|2G|6800GS|SBAUDIGY

Reply 39 of 60, by hasnopants

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Bringing this one back from the dead...

I think I finally figured out why the voodoo2s would not run at 1024x768 in SLI. I narrowed it down to 1 card by using PC mark 99 to blast a 32 mb texture at 800x600 at the card in a benchmark. One of the cards was able to pass the test, but this card failed it immediately and locked up the system. Upon further inspection I found this!

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On one of my cards, it looks like a piece is missing next to one of the memory module's backside. The location is labeled 'C119'. Anyone have any clue what that is and if its easily self-repairable? My first guess is that its a resistor...but I really don't know too much about electronics to say for sure.

I went ahead and ordered a replacement card, I have no idea if that was like that the whole time, or if it broke in shipping when I first got the card or if I did it. But it seems like a likely cause to why the card works fine, generally, but when I push it to the limit it flakes out.

Current Systems:
DIP40|8088|640K|HERCULESGB102|PCSPKR
DIP40|V20|640K|VGA|ADLIB/TNDY/COVOX
S7|P233MMX|128M|S3ViRGEDX/DM3D|SB16
S370|P600MMX|256M|SIS630/DM3DIIX2|SBLIVE!5.1
S775|P43.4|2G|6800GS|SBAUDIGY