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Dumb SLI question

hunterjwizzard

hunterjwizzard

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Shopping for a pair of graphics cards for my dual opteron machine. Its XP x64, so a lot of cheap options. But I need single-slot card since I'd like other peripherals.

I'm presently leaning towards a geforce 9800, on the basis I already have an 8800 systen and that seems to be the fastest generation that can be had for $20-30 a card.

Now here's the stupid question: all the single slot variants I'm seeing only have the 1 connector for SLI whereas the dual slotters have 2 headers. I want to know: why? Two is better than one but to the best of my understanding the only difference between the card models is the size of the heatsink.
 
The only 9800 series card that I'm aware that has a single slot variant is the 9800GT. The number of SLI connectors was dependent on whether the board partner opted to have one or two connectors. ASUS had the EN9800GT with two connectors. I don't recommend single slot cards from this era because of the ROHS solder issue. Single slot cards run hotter and have higher failure rates on already high failure rates in those generations. The 9800GTX and GTX+/GTS250 are all two slot cards as far as I'm aware.

Depending on what 8800 you have, a 9800GT is not going to be any better than what you already have. There were three 8800GTS variants (a 320M and 640M based on the G80 core) and a GTS 512 variant based on the same G92 core as the 9800GTX, just at a lower clock speed. The 8800GTX is faster than a 9800GT. At best, you'd be wasting money on a sidegrade.
 
The 8800s are in a different system.

I have to go with a single slot solution because I have dreams of actually using expansion cards in this system. I suppose I could break down and live with a none-SLI setup(if you can all that living). But a A dual slot GPU covers up the one PCI slot!
 
To clarify: I have an existing single-processor system with 3x8800s in SLI. I love it. But For this new system, dual processors with SLI, I wanted to see if I could find a slightly faster card. Sounds like I should make due with more 8800s though.
 
I wonder if SLI will even work in that system. If the PCIe slots are connected to different CPUs, it probably won't work. If it did, it'd probably clog up every bus in the system when the application was on the other CPU.
 
That is something of a question. I've been able to find several accounts of people using SLI on this machine, but some sources claim it only works with Quadro graphics cards while others just indicate it works with SLI. This is part of why I'm looking at cheaper cards, I'd hate to spend a bunch of money only to find it doesn't work.
 
Motherboards have to be SLI or crossfire capable and some with dual PCIE slots are not especially server boards.
 
Its not a serverboard, its a high-end workstation board. Documentation is scant but I've found articles that indicate its SLI-capable.

I do have the wrong graphics cards. Probably I should drop a spare disk in there load up windows 7 and test it.
 
The 8800 series and derivatives (ended with the 9800 GTX+ GTS 250) were nice cards.

In my collection I have/had the 9800 GTX+ in SLI, 8800 GTX, 8800 GS 320MB SLI, 8800 GT 512MB, 8800 GTS 640 SLI, and GTS 250.

3-way SLI never made much sense since more than 2 cards usually didn't add much and was worse when they were CPU limited.
 
Unknown_K said:
3-way SLI never made much sense since more than 2 cards usually didn't add much and was worse when they were CPU limited.
Click to expand...
Some things aren't about making sense.

In this particular circumstance my 3-way SLY system came about when I realized I had 3 identical cards, a 3-way SLI capable motherboard, and a 3-way SLI bridge. I couldn't stop giggling until I'd put the whole thing together.
 
I have one 3-way SLI bridge but only 2 cards using it (Geforce GTX 260 Core 216's).

For a while there I was going nuts collecting multiple identical cards (same brand and model) for SLI or crossfire plus I even got a Radeon HD4870X2 card.

I think SLI died with the GTX 1080 because games quit supporting it, not sure when crossfire died as AMD quit using bridges and just used the PCIE BUS for that.
 
SLI is not dead, but nVidia started severely restricting which cards could use it for some reason. I have 1070s in my "modern" gaming rig doing SLI. If you go to the 2000-series, only like the top-end most card can do it(2080, 2090? I stopped paying attention when those things cost too freaking much). Its the same on the later generations.

I think it also still has use-cases in certain workstation applications. I don't really know. All I know is I couldn't afford an SLI system when they were the new hotness, but 8800s are like 20 bucks now so I can build all the SLI systems I want.
 
SLI died for a multitude of reasons, but the biggest was that developers were tired of supporting it. It was a huge headache to support SLI profiles, that needed adjustment every time the video driver was changed. It also never really worked well outside a small number of titles that were heavily optimized to use it. Stuttering, midget frames, sync issues and other problems plagued both SLI and Crossfire setups their entire lifespan. Another reason is that single GPU ASICs became powerful enough to run demanding titles on their own at acceptable performance.

Had SLI or Crossfire worked like 3dfx's scan line interleave did, where it was done purely in hardware and required no game intervention, it may have well fared a lot better. In 3dfx's case, the game didn't need to explicitly support scan line interleave to use it, it was all transparent. The driver just told the game what display modes were available.
 
The funny part is the SLI name comes from nVidia's acquisition of 3dfx. One wonders why they didn't copy the style?
 
Back around 2013-14 I had a Gigabyte 990 board with a Phenom II X6 1065T. I had pair of Radeon Ghost 7950's which were wired to Crossfire. I thought I had a pretty good setup but it had a hard go with the benchmarks of that time. Any comparable Intel rig would eat its lunch but I was a huge AMD fan back then. It was just a cut below being a top end machine. So I built a Z100 rig in 2015 with the I 6700K but that's another story. I really can't remember if Crossfire was that effective as I thought it would be. The graphical content/quality of games back then was no where near comparable to today's offerings. So, I would find a simple benchmark and observe the FPS with both configurations. I would be real interested in that triple config. BTW Happy New Year.
 
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Games that take advantage of crossfire/SLI do see a big jump in FPS in higher resolutions while games that don't support it might see the same or even lower FPS.

I forget how games seen single cards with multiple GPU's like the HD 4870x2 I mentioned.
 
I don't really 'game' much or very seriously, so real performance is not very important. I'm far more concerned with how the machine makes me feel.
 
hunterjwizzard said:
The funny part is the SLI name comes from nVidia's acquisition of 3dfx. One wonders why they didn't copy the style?
Click to expand...

It wasn't copied because it was grossly inefficient. Scan Line Interleave duplicated the entire scene between both cards, with the only difference is that each card rendered 50% of the screen in alternating scan lines. Essentially the only thing this did was double the fill rate and nothing else, which is why games didn't necessarily run better in SLI mode, it just allowed for higher resolutions.

AFR mode (alternate frame rendering) was used by ATI on their Rage Fury MAXX and later ATI/AMD cards, and I believe was also an option on Nvidia cards. It had the same but worse problems. Instead of each card rendering the same scene, they rendered successive frames. So if one frame took longer than the other to render, this caused stuttering and inconsistent performance. This could somewhat be worked around by artificially limiting the maximum allowed frame rate, but it didn't completely resolve the problem.

Unknown_K said:
I forget how games seen single cards with multiple GPU's like the HD 4870x2 I mentioned.
Click to expand...

Dual GPU cards are basically two separate cards that are connected over a PCIe bridge. These types of cards allowed quad SLI / crossfire without needing monster motherboards to fit four dual slot cards. The system would see them as two distinct cards.

 
Yea, Quad SLI/X-fire!
I had a system with 2 4870X2 crossfired back in the day. My monitor app. showed most all games were using only one core. Crisis did work well but talk about case fan noise, wow. It was like a space heater.
 
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