This $5000 PC From Just Four Years Ago SUCKS

Overview / Main claim

• The video tests whether running two older high-end GPUs with SLI (specifically two RTX 3090 Ti cards) can still compete with a modern single-card flagship (an RTX 5090).
• While SLI was once seen as groundbreaking, the host argues it’s effectively dead for gaming today, mainly due to:
  • driver/game support limitations
  • scaling inefficiencies
  • micro-stutter
  • extreme power/heat and noise

Tech background: What SLI is and how it changed

• SLI (Scalable Link Interface) allows two matching GPU cards to work together, coordinating rendering via a bridge.
• The host explains that SLI depends on tight synchronization/communication between the cards, which often means you get more waiting and more steps, not true 2× performance.

Bridge evolution mentioned

• Early bridges were too slow for modern coordination demands.
• Progression:
  • HB (High Bandwidth) bridges (2016)
  • NVLink bridges (2018) up to ~50 GB/s
  • 30-series NVLink bridges up to exceeding ~100 GB/s (used in the test)

Test setup and baseline performance

Baseline hardware

• 1× RTX 3090 Ti Founders Edition
  • 24GB GDDR6X
  • 384-bit bus
  • “a little over 10,000 CUDA cores”
  • Boost clock around ~1860 MHz
• The host notes it’s “not fastest anymore,” but it’s still “clearly” strong relative to its era.

Power and efficiency notes

• In 3DMark, power draw reached nearly 600W.
• In real games, performance “holds up pretty well,” but efficiency is worse than newer cards.

Adding the second GPU: performance gains and what prevents “double FPS”

2× RTX 3090 Ti in SLI

• Synthetic benchmarks show a large uplift (the host mentions ~15,000 and “nearly double” graphics score).
• The host stresses that synthetics overstate scaling because the CPU stayed the same.

Real-world scaling limitations

• The setup is described as primary/secondary:
  • The secondary card can’t start until it receives instructions from the primary.
  • The primary can’t output the final result until it “stitches together” the combined work.
• Result: even under ideal conditions, you never realistically get 2× frame rate.

Troubleshooting & driver/profile issues (practical hurdles)

• A major frustration: per-application SLI settings vanished from the NVIDIA Control Panel.
• The host found SLI settings only in Profile Inspector, including:
  • an “SLI compatibility bits” hex field
  • suggesting manual/unclear compatibility tuning
• For the 3090 Ti specifically:
  • SLI ignores profiles for DirectX 11 and older games (described as enforced by driver behavior).

Driver availability issue

• The host reports the Nvidia driver repository looked “broken” at the time.
• Guru3D provided older Nvidia drivers.

A key fix

• Shadow of the Tomb Raider random startup crashes traced to the Steam overlay.
• Disabling Steam overlay enabled SLI gaming.

Main negative: micro-stuttering

• The host identifies micro-stutter as a core SLI failure mode:
  • because the cards can wait on inconsistent data coordination
  • frame times become irregular
• This produces hitches/stutters, even when the FPS counter looks acceptable.

Power, heat, and noise (hardware practicality)

Power impact

• With two 3090 Tis:
  • In-game system power reported over 1,000W
  • CPU is “less than 100W,” implying the GPUs dominate thermals.

Physical impact

• The system is described as extremely loud.
• GPU temperature around ~90°C on GPU 2, near throttling.
• A FLIR thermal camera is mentioned as confirming severe heat (including heat-sink external temps and “toasty” areas).

Game support / real scaling observations

• Some games run well, but scaling is inconsistent:
  • One title reportedly shows very good averages and 1% lows.
  • Another title feels “amazing,” with the host attributing improvements more to DirectX/multi-GPU support than classic Nvidia SLI itself.
• The host observes around ~60% GPU utilization per card in one example, suggesting:
  • SLI isn’t fully feeding the GPUs
  • multi-GPU benefits depend heavily on the workload/game

Where SLI “dies” (host’s conclusion on why it’s not worth it)

The host argues SLI is a bad deal today because of:

• limited game support
• slight-to-moderate gains instead of doubling
• micro-stutter risk
• massive power/heat/noise
• overall, taking this route to compete with modern single GPUs is described as “dumb” for gaming

AI/compute exception: NVLink and 3090 Ti legacy

• The host pivots to an exception:
  • 3090/3090 Ti are “legendary” budget AI cards due to NVLink
  • NVLink enables high-speed access between GPUs’ memory for certain workloads.
• A theory is mentioned:
  • disabling/removing NVLink in consumer cards may be tied to avoiding competition with Nvidia’s AI product line (framed as a “tinfoil hat theory”).

Direct comparison: 2× RTX 3090 Ti (SLI) vs RTX 5090 (single GPU)

VRAM expectation challenged

• The host disputes the idea that 5090’s 32GB VRAM is a downgrade.
• Reasoning:
  • In SLI, both cards generally must store required frame data independently, so summing VRAM is misleading.
• Also:
  • The SLI bridge bandwidth is said to be much lower than local GPU memory bandwidth (described as ~1/10 and with higher latency).

Memory/bandwidth improvements claimed

• RTX 5090 uses:
  • GDDR7
  • 512-bit bus
• Claimed improvement:
  • ~80% real-world bandwidth increase vs one 3090 Ti.

Architecture/software improvements

• Newer tensor and ray tracing cores.
• Better software support for modern features, including multi-frame generation options.

Power/thermals comparison

• RTX 5090 is said to use far less power than the dual 3090 Ti setup:
  • host cites ~600W peak system with the 5090
  • versus >1,000W earlier with SLI

Performance result (as reported)

• The host reports the 5090 scores even higher than two 3090 Ti, but not by as much as expected (mentioned ~16,230 synthetic score).
• In real games, the host claims a single GPU tends to beat multi-GPU, even in “cooperative” situations.

Final verdict on SLI today

• SLI gaming is “well and truly dead.”
• NVLink still exists on Blackwell, but Nvidia appears to restrict it mainly to:
  • professional/workstation products
  • enterprise GPUs for large-scale AI/compute linking
• The host also claims what they tested as “SLI” depended heavily on DirectX 12 multi-GPU support, not Nvidia’s classic SLI feature set.

Speakers / sources (as referenced)

• Main speaker/host: Unnamed narrator (appears to be the YouTube creator).
• Products/tools cited:
  • NVIDIA (SLI/NVLink, driver behavior, control panel/profile inspector)
  • Guru3D (older Nvidia drivers)
  • FLIR (thermal camera for heat verification)
  • Ridge (sponsor; referenced for Father’s Day sale)
• Games mentioned:
  • Shadow of the Tomb Raider
  • “Crest Smasher”
  • Strange Brigade