Game stutters on a PC that should demolish everything you throw at it? A high-end rig — say an Intel i7-13700K with an RTX 5070 Ti — hitching in PUBG is one of the most maddening problems in gaming, precisely because nothing is obviously wrong. Before you spend a weekend reinstalling drivers and dialling settings down, there’s a two-minute BIOS change that fixes a surprising number of cases: forcing your GPU slot from Auto/Gen 5 down to PCIe Gen 4.
Downgrading sounds backwards. Here’s why it works.
Why your GPU doesn’t need PCIe 5.0
Cards like the RTX 5070 Ti are engineered around PCIe 4.0-class bandwidth, and at x16 they don’t come close to saturating even that. Your Z790 board and CPU proudly advertise PCIe 5.0 — but for the graphics slot, that headroom is doing nothing for your frame rate. Independent testing consistently shows the difference between Gen 4 and Gen 5 x16 for gaming is within the margin of error.
What running the newest link speed can do is make life harder for the signal. PCIe 5.0 doubles the signalling rate, which halves the margin for error across the slot, the traces and any riser cable in the path. On Auto, the platform will happily pick the highest speed it can negotiate — even when a slightly lower one would be electrically far more comfortable.
How Gen 4 smooths out game stutters
It removes link re-training from the equation. A marginal Gen 5 connection can silently drop and re-train the link, or bounce between power states — and each of those events can land as a frametime spike. You won’t see it in average FPS; you’ll feel it as a hitch at the worst possible moment. Locking the slot to Gen 4 gives the link generous signal margin, so it settles and stays settled.
It prioritises consistency over a number on a box. Competitive shooters like PUBG, CS2 and Valorant live and die on frame delivery, not peak bandwidth. A rock-steady Gen 4 x16 link beats a nervous Gen 5 one every single time.
It runs cooler and calmer. Gen 5 PHYs draw more power and run warmer. It’s a small factor, but on long sessions every bit of electrical calm contributes to steadier behaviour.
Using a vertical GPU mount or riser cable? This fix applies to you double. Most affordable risers are Gen 3/Gen 4 rated at best — running Gen 5 through them is the classic recipe for stutters, black screens and even boot loops.
The two-minute BIOS fix
Restart and tap Delete (or F2) during boot to enter the BIOS.
Head to Advanced → Chipset / PCIe Configuration (naming varies by board — on ASUS it’s under Advanced → System Agent).
Find the primary PCIe x16 slot speed setting, currently on Auto or Gen 5.
Set it to Gen 4, then save and exit (F10).
That’s the whole job. Your frame rates will look identical — the point is that the frames now arrive evenly.
How to verify it worked
Open GPU-Z and check the Bus Interface line reads x16 4.0 under load (click the “?” for a quick render test). Then play the game that stuttered — or better, record a session with CapFrameX before and after and compare the 1% lows and frametime graph. Smoother line, same FPS: job done.
When this isn’t your problem
Honesty corner: forcing Gen 4 fixes link-related stutter. If your game stutters because of shader compilation, a background process, thermal throttling, or a genuinely mismatched CPU/GPU pairing, this change won’t touch it. Two of our free tools help narrow that down: the bottleneck calculator shows whether your pairing is the limiter, and the FPS estimator tells you what frame rates your hardware should be delivering. And if a brand-new build stutters before it even boots properly, start with our new PC not booting guide.
The bottom line: locking your GPU to PCIe Gen 4 is free, takes two minutes, is completely reversible, and costs you no performance. For stutter-sensitive competitive play, it’s one of the best effort-to-payoff tweaks there is — the right technology for your hardware beats the newest technology on the spec sheet.
Still stuttering after the fix? Bring it to the bench. We diagnose stutters, hitches and “it should run better than this” machines in Harrow — no fix, no fee.
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