That is proper, SLI — Nvidia’s out of date multi-GPU tech that Benchmark Labs managed to run utilizing some unknown SLI-enablement magic. The channel was in a position to run SLI decently nicely in a number of DX11, DX12, and Vulkan titles, however finally the 3090s could not beat the RTX 4090 (although they received shut).
Earlier than we soar to the outcomes, it is value noting that each one of this must be taken with a grain (or a number of) of salt. SLI has been unsupported for years at this level, and getting it to work with most fashionable titles — particularly with DX12 and Vulkan — would require…unorthodox strategies. We’re undecided how Benchmark Lab managed to allow SLI in a lot of the video games examined — once more, particularly the DX12 variations — or if the outcomes had been doctored or extrapolated. That mentioned, the outcomes are fairly fascinating (if they’re, certainly, correct).
Benchmark Lab examined 9 video games: Spider-Man Remastered, Cyberpunk 2077, Watch Canine Legion, Microsoft Flight Simulator 2020, Minecraft RTX, God of Warfare, Witcher 3, Horizon Zero Daybreak, and Learn Lifeless Redemption 2. Testing was carried out at 4k decision utilizing quite a lot of totally different high quality settings and DLSS modes.
In Spider-Man Remastered, with maxed out settings (Ray Tracing and DLSS Balanced mode enabled), the RTX 3090s in SLI achieved 80 – 85 frames per second (fps) on common, whereas the RTX 4090 managed a noticeably greater 95 fps common.
In Cyberpunk 2077, with maxed out settings (Ray Tracing and DLSS Balanced mode enabled), the RTX 3090s in SLI managed 50 fps whereas the RTX 4090 averaged 70 fps.
In Watch Canine: Legion, with maxed out settings (Ray Tracing and DLSS High quality mode enabled) the hole closed just a little: the RTX 3090s in SLI averaged 73 fps, whereas the RTX 4090 averaged 80 fps.
The outcomes had been even nearer in Microsoft Flight Simulator with maxed out settings (Ray Tracing and DLSS High quality mode enabled). The RTX 3090s in SLI averaged 80 fps, whereas the RTX 4090 averaged 83 – 85 fps. (Nevertheless, word that Microsoft Flight Simulator is thought to be CPU-bound, particularly at greater body charges.)
In Minecraft RTX, with max settings (Ray Tracing enabled), the RTX 3090s in SLI averaged 70 fps whereas the RTX 4090 hit a barely greater common of 75 fps. And in God of Warfare at max settings (DLSS High quality mode enabled), the RTX 3090s in SLI hit a median of 103 fps whereas the RTX 4090 did fairly a bit higher with a median of 120 fps.
For the remainder of the titles, take a look at the video under:
RTX 3090 SLI Is The Solely Setup That Can Get Shut To The RTX 4090
Except the Cyberpunk 2077 outcomes, the RTX 3090s in SLI had been round 8 – 15% slower than the RTX 4090. For an SLI implementation, this is not dangerous in any respect — and it is the one GPU configuration we have seen to date that may get near the RTX 4090’s efficiency bracket. For some perspective, the next-closest GPU is the RTX 3090 Ti — which trails the 4090 by over 50% based mostly on our exams.
Sadly, the 3090s in SLI setup wasn’t getting used to its full potential, because the secondary 3090 persistently maxed out at 45% utilization. This is among the pitfalls of SLI setups, through which dangerous optimization results in less-than-superb GPU utilization on the secondary card. In concept, if we may get wherever near 100% utilization on each GPUs, we’d in all probability see the 3090s in SLI outperform the 4090 by an excellent margin.
However the possibilities of that occuring are extraordinarily unlikely, since Nvidia formally killed off SLI within the type of bodily bridges with the RTX 40 sequence. SLI assist has dwindled a lot over the previous a number of years that it is mainly solely helpful in artificial benchmarks at this level.
There are technically methods of enabling SLI (unofficially) in video games that do not assist it — like within the case of the benchmarks seen on this video. However these outcomes are unpredictable at greatest, and normally lead to system instability or extreme micro-stuttering issues whereas gaming.
There may be some hope for SLI, nonetheless. Multi-GPU workloads are quite common within the enterprise area, and Nvidia even has multi-GPU applied sciences that do not require an NVLink or SLI bridge.
On the gaming aspect, fashionable APIs equivalent to DX12 and Vulkan do have the potential to render frames to 2 fully totally different GPUs in tandem. So there’s an opportunity multi-GPU tech may make its method again to the gaming area, finally (however whether or not builders wish to assist multi-GPU know-how for gaming is a distinct story).