Why Arsenal lags
Arsenal renders fast-moving players, projectiles, and death animations simultaneously. On budget hardware, the visual effects during firefights — explosions, kill effects, multiple character models spawning — spike GPU usage and drop frames mid-firefight.
The input lag problem is separate from frame rate. A player running at 60 FPS with Windows fullscreen optimizations enabled has more input lag than the same player at 55 FPS with them disabled. In a fast FPS, that difference shows up in your aim. You fire, and the bullet lands slightly late relative to where your cursor was.
The two problems need different fixes. Frame rate comes from graphics settings and hardware load. Input lag comes from fullscreen mode and GPU driver settings.
Fix frame rate first
Set your power plan to High Performance before anything else. Press Win+R, type powercfg.cpl, press Enter. On a laptop, keep it plugged in.
In Arsenal, press Esc to open the menu. Go to Settings and set Graphics Mode to Manual. Set Graphics Quality to 3 or 4 — not lower. Going below 3 causes texture pop-in during fast movement, which is more disorienting than slightly lower FPS.
Turning shadows off is worth more than you expect. Arsenal's shadow rendering is expensive relative to what it adds visually. On integrated graphics, disabling it can add 10–15 FPS.
Fix input lag
Disable fullscreen optimizations for Roblox. Press Win+R, type %localappdata%\Roblox\Versions, press Enter. Open the newest version folder. Right-click RobloxPlayerBeta.exe, choose Properties, go to Compatibility, and check "Disable fullscreen optimizations". Click OK.
If you have NVIDIA: open NVIDIA Control Panel, go to Manage 3D Settings, Program Settings, add RobloxPlayerBeta.exe. Set Low Latency Mode to Ultra. Set Power Management Mode to Prefer Maximum Performance. This tells the GPU to submit frames just-in-time, which removes the small queue of pre-rendered frames that adds latency.
If you have AMD: open Radeon Software, add Roblox under Gaming, enable Radeon Anti-Lag, and set Wait for Vertical Refresh to Off.
Disable Xbox Game Bar
Game Bar records video in the background by default. Press Win+I, go to Gaming, turn off Xbox Game Bar. Then go to Gaming, Captures, and turn off background recording. On integrated graphics, this alone can recover 5–8 FPS.
What to expect
On integrated graphics (Intel UHD), these changes typically bring Arsenal from 20–35 FPS to 40–55 FPS stable. Firefights will still drop below that, but far less than before.
On a budget dedicated GPU (GTX 1650, RX 580), you should reach stable 60 FPS in most situations. The input lag fix will be noticeable — aim feels tighter even at the same frame rate.
On a mid-range or better GPU, you are already hitting your monitor's refresh rate or close to it. The Low Latency Mode change is the most impactful one for you.